Next Article in Journal
The Impact of the Neighborhood Built Environment on the Walking Activity of Older Adults: A Multi-Scale Spatial Heterogeneity Analysis
Next Article in Special Issue
Influence of Pastoral Settlements Gradient on Vegetation Dynamics and Nutritional Characteristics in Arid Rangelands
Previous Article in Journal
Profound Impact of Economic Openness and Digital Economy towards a Sustainable Development: A New Look at RCEP Economies
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Sustainability
Volume 14
Issue 21
10.3390/su142113930
sustainability-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Recovery and Germination of Malus sieversii (Ledeb.) M. Roem. (Rosaceae) Seeds after Ingestion by Cattle, Horses, and Sheep

by
Jiang Xu
,
Zongfang Zhang
,
Shilin Bai
,
Yaya Lv
,
Xiaojun Shi
* and
Dunyan Tan
*
College of Life Sciences, Xinjiang Agricultural University, Urumqi 830052, China
*
Authors to whom correspondence should be addressed.
Sustainability 2022, 14(21), 13930; https://doi.org/10.3390/su142113930
Submission received: 26 September 2022 / Revised: 19 October 2022 / Accepted: 24 October 2022 / Published: 26 October 2022
(This article belongs to the Special Issue Grazing Management, Conservation and Climate Mitigation on Rangelands)
Browse Figures
Review Reports Versions Notes

Abstract

:
Livestock can transport seeds long distances by endozoochory due to their large home range and capacity to move among different habitats. However, differences in digestive system and body size between different livestock species may result in variations in the dispersal of domestic livestock. To test such effects, we explore the effects of endozoochorous seed dispersal of Malus sieversii by three livestock: cattle, horse, and sheep in the Ili Botany Garden, northwest of China. We collected seeds of M. sieversii and fed them to cattle, horses and sheep. After feeding, we collected all the seeds from their feces every 24 h for 6 days and determined the seed recovery percent, mean retention time, and germination percent of seeds after the effects of the digestive tracts of those three livestock species. Seed recovery percent in three livestock species feces were cattle (CS) (54.05%) > horse (HS) (4.83%) > sheep (SS) (0.45%). The mean retention time of seeds in the digestive tract of cattle, horses and sheep were 53 h, 57 h, and 45 h. The seed weight and seed coat thickness decreased significantly after the treatment of the digestive tract. After 80 days cold stratification of seeds, the germination percent of CK, CS, and HS were 61%, 69%, and 18%, respectively. The results indicated cattle is an effective seed disperser of M. sieversii, with a recovery and germination percent in endozoochorous seed dispersal by cattle than that of horse and sheep. Our findings may also provide a theoretical basis about regarding seed-centric grazing management decisions and keeping horse and sheep out of pastures during the fruit of M. sieversii shedding period.

1. Introduction

Seed dispersal is defined as the process of a plant’s diaspore leaving the parent plant and reaching a safe habitat suitable for germination, reproduction, and settlement, and is an important stage in plant life histories [1,2,3], and has important implications for plant survival, reproduction, and ecological evolution [4,5]. Seed dispersal methods include wind dispersal, water dispersal, and animal dispersal [6]. Wind dispersal and water dispersal refers to the dispersal of diaspore with appendages under the effect of wind or water forces [7,8]. Animal dispersal is the dispersal of plants that produce adhesive seed attachments to mammalian fur or produce tasty fruits to attract animals to feed on them [9,10]. Depending on the dispersal mechanism, animal dispersal can be classified as epizoochory [9,11], synzoochory [12], and endozoochory [13,14], Among them, endozoochory is one of the most common modes of dispersal. Endozoochorous seed dispersal is defined as the swallowing of fruits and the dispersal of seeds through ruminating and chewing or feces by animals [15]. Animals are able to determine whether a fruit is ripe or not by information such as the color and smell of the fruit [16,17]. When the ripe fruit is consumed by animal, the seeds are excreted away from the parent plant, thus allowing effective dispersal, and the distance of seed dispersal depends on the retention time of the seeds in the animal’s digestive tract [18].
Livestock are known to play an important act as seed dispersers by feeding on their fruits or seeds and excreting ingested seeds in feces in livestock farming systems [19,20,21,22]. However, it is also recognized that livestock vary in the effect of the seed recovery, characteristics, and germination they provide to seeds [23,24]. Different livestock have various chewing intensities of food during the feeding process [21], so the recovery percent of the same seeds after digestive effects by different livestock are varied [25]. Previous research found that the morphological characteristics of the seeds of 28 grasses changed significantly after rumen effects, and the seed length, width, height, and 100-grant weight decreased within the digestion time [26]. The digestive tract also has different effects on the germination of different seeds, most legumes are physically dormant and seed germination percent increases significantly after passing through the digestive tract [27]. In contrast, most seeds with physiological dormancy, morphological dormancy, morpho-physiological dormancy, or non-dormancy have a significant decrease in germination percent after passing through the digestive tract [24]. In all, the effect of endozoochorous dispersal on seed germination depends on seed traits such as size, shape, permeability, thickness of the seed coat, or type of seed dormancy [28,29,30], and on animal traits such as body size, digestion modes (ruminant or not), and feeding preferences [31,32]. Howsoever, endozoochorous seed dispersal by livestock plays an indispensable role for seed dispersal in farming systems.
Malus sieversii is a species of Malus in the Rosaceae family and an ancestor of cultivated apples (M. domestica), which contains valuable genetic resources for the genetic improvement of apple and provides important ecological service value [33,34]. This species is the dominant tree in the wild fruit forest which covers a large area in Xinjiang of China, Tajikistan, and Kyrgyzstan [35]. They often grow on mountain slopes, hilltops, and river valleys at an altitude of 1100–1600 m [33]. In the last three decades, due to climate change, pests, and disease outbreaks, mass mortality of M. sieversii has occurred [36,37]. To protect this important germplasm, wild apple has been listed in the red list of IUCN and is a Grade II protected plant in China [38,39].
The interactions of plants and animals in an ecosystem are critical to their function, biodiversity, and restoration success [40]. Large herbivores in the forests are believed to reduce weed biomass and competition between weeds and trees [41], and feces from livestock can also fertilize trees [42]. In our field observation, during the fruit of M. sieversii shedding period (July–September) each year, we can observe that grazing livestock consume its fruit and find M. sieversii seeds in their feces (Figure 1) in the Ili Botanical Garden. Cattle, horses, and sheep are so numerous that they consume most of the fruits. In spite of this, as to date no study about endozoochory by livestock has been conducted in the wild fruit forest, knowledge about the role of livestock in the dispersal of plant species of this area is scarce, especially as concerns endemic and endangered plant species.
In this research, we aim to study the effect of endozoochorous seed dispersal of M. sieversii by cattle, horses, and sheep. Our result will provide reasonable grazing suggestions for local forestry management departments to facilitate the restoration of endangered species and promote sustainable development of animal husbandry. We propose the following two hypotheses: (i) seeds have different recovery percentages after passing through the digestive tract of cattle, horses, and sheep since these three livestock have different oral cavity sizes and feeding patterns, with the smaller oral cavity of sheep chewing the seeds more finely and therefore having a lower recovery percent. (ii) Seed morphology and germination percent will be differently affected because of differences in digestive tract structure (ruminants and non-ruminants), pH, and digestive enzymes in cattle, horses, and sheep.

2. Materials and Methods

2.1. Study Site

This study was carried out at Ili Botanical Garden, Xinyuan County, Xinjiang, China (43°41′ N, 83°27′ E, altitude 1400 m), a part of the Ili Valley. The Ili Valley is located in Central Asia, surrounded by mountains on three sides, and far from the ocean. Due to its unique topography and mountain orientation, it allows air currents from the Atlantic, Mediterranean, and Black Sea to flow up the valley and form precipitation [43]. The annual average temperature in the Ili Valley is 8.1 °C, the annual average precipitation is 480 mm [44].
In the floristic zonation of China, the angiosperm flora of the Ili Valley was placed in the Paleo-Mediterranean flora. There are 1655 species of angiosperms, belonging to 486 genera and 83 families [43]. The woody plant of the study site is dominated by M. sieversii with a few companion species of Armeniaca vulgaris, Prunus cerasifera, Picea schrenkiana var. tianschanica, Betula tianschanica, Populus tremula, and Crataegus songorica, etc., [45]. The herbaceous plants mainly include Festuca gigantea, Origanum vulgare, Achillea millefolium, Bromus benekenii, Koeleria cristata, etc., and soil with a high organic matter level [46].

2.2. Collection of Seeds and Feeding

We collected seeds from the one mother plant from July to September 2021 at the Ili Botanical Garden, China, and the collected seeds were stored in envelope bags in a cool, dry place for further testing. We chose 3 cattle, 3 horses, and 3 sheep. The ages of cattle, horses and sheep were about 4 years, 5 years, and 2 years, respectively, and the body size were similar between conspecifics. Each animal was put in an individual room with sufficient water and forage for 3 days to adapt to the test environment. A total of 1500 seeds were mixed into each livestock feed, after all feeds were consumed, by counting the number of seeds remaining in the trough we calculated the actual number of seeds ingested by each livestock. All experimental procedures involving animals were approved by the Animal Welfare and Ethics Committee of Xinjiang Agricultural University, Urumqi, Xinjiang, China.

2.3. Recovery Seeds from Feces

Fecal collection started 24 h after feeding and continued for 6 days. Each daily fecal material was carefully collected from the room until room became completely clean. Cattle feces and horse feces were washed in the water stream through a wire sieve (8 mesh) until most of the excrement was washed away, and we picked out the seeds in cattle feces and horse feces in the residue. However, sheep feces were too hard to be washed away, so we crushed each one by hand to collect the seeds in sheep feces. Seeds collected were stored in envelope bags in a cool, dry place for further testing, the calculation of seed recovery percent (SRP) and the mean retention time (MRT).
S R P = N R / N I × 100 %
where NR is the number of recovered seeds and NI is the number of ingested seeds.
M R T   h = ∑ n = i n D i S i / ∑ n = i n S i × 24
where Di is the number of days to recovery seeds and Si is the number of seeds recovered from the feces on day i [47].

2.4. Modification of Seed Traits

We compared post-ingestion seed characteristics and germination performance of cattle-ingested, horse-ingested, and sheep-ingested seeds (hereafter “CS”, “HS”, and “SS”, respectively) to control seeds that had not transited through any livestock digestion system (hereafter “CK”).
Seed coat permeability—30 intact seeds each of CK, CS, and HS were randomly selected and placed in Petri dishes with distilled water for 24 h [48], the seeds were weighed at 0, 0.25, 0.5, 1, 2, 4, 6, 9, 12 and 24 h with an analytical balance (ME204E, Mettler Toledo, Zurich, Switzerland). After 24 h, the seeds were taken out and placed in a dry Petri dish, and the seeds were weighed at 0, 1, 2, 3, 4, 6, 8, 10 and 24 h, SS recovery in quantities was too small to be tested.
Seed shape and quality—10 intact seeds each of CK, CS, HS and SS were randomly selected, and the length, width and height of the seeds were measured with a digital caliper; 100 intact seeds each from CK, CS, HS and SS were selected, weighed with an analytical balance. We calculated mean cubic diameter (MCD) of seeds based on MCD = (a1 × a2 × a3)1/3, a1, a2, a3 replaced the length, width and height of the seeds, respectively [49].
Seed coat thickness—5 intact seeds each of CK, CS, HS and SS were randomly selected, the seeds were cut in half along the middle protrusion of the seeds, one half of the seeds were fixed on a foam plate with the cut side up, and we placed the foam plate with the seeds fixed on it under a stereomicroscope (SMZ25, Nikon, Tokyo, Japan) at 50 times magnification to take a photograph and mark scale. The seed coat thickness in the photograph was measured using the ruler tool by Photoshop 2020.
Seed coat structure—10 seeds each of CK, CS, HS, and SS were randomly selected, washed with distilled water, and dried. The seeds were first placed under a stereomicroscope at a magnification of 30 times, and complete photographs of the seeds were taken. Then the seeds were plated by ion sputtering device (E-1045 ion sputter, Hitachi, Tokyo, Japan) and we observed seed coat morphology with a scanning electronic microscope (Supra55 VP, Zeiss, Oberkochen, Germany) at a magnification of 300 times to reveal the destruction of the seed coat by different digestive tract treatments of livestock.

2.5. Seed Vitality

We randomly selected 100 intact seeds each of CK, CS, HS and SS, soaked them in distilled water for 6 h to make the seeds fully absorb water, and prepared TTC solution with a concentration of 0.1%. We stripped the seeds of their seed coats and placed 25 peeled seeds in each Petri dish, 10 mL of TTC solution was added, and each treatment was replicated 4 times. The Petri dishes were placed in controlled environment chambers with 30 °C for 12 h [50]. After 12 h, the Petri dishes were removed and we checked the seeds for staining: if the embryo tissue were stained pink/red, then the seeds were viable. The number of stained red seeds were counted, and the percentage of viable seeds was calculated. SS recovery in quantities was too small to be assessed.

2.6. Germination Trials

According to the classification criteria of seed dormancy by Baskin (2014), there is physiological dormancy in Malus, and seeds need to undergo cold stratification for a certain period before germination [51]. Liu et al. (2021) found that 60–70 d of cold stratification was required to break the dormancy of M. sieversii seeds, and the maximum germination percent was reached at 80 d of cold stratification [52]. The seed batches were placed on the surface of the moist filter paper in Petri dishes, and the Petri dish was wrapped in tinfoil and placed in the refrigerator at 4 °C for cold stratification [53]. We conducted a germination test at 60, 70, and 80 days of cold stratification. The seeds were removed and washed with distilled water, and the seeds from the three treatments were placed in Petri dishes containing two sheets of filter paper, and 25 seeds were placed in each Petri dish. The germination tests were conducted in controlled environment chambers with 12 h light at 25 °C and 12 h of darkness at 15 °C, 4 replicates for each treatment. The germination tests were terminated when no seeds germinated for a week. The filter paper was remoistened with distilled water as necessary. The seeds in Petri dishes were checked every day. Seeds were considered to have germinated when the radicle broke through the seed coat. Seeds that had germinated were counted and then removed from the dishes.

2.7. Statistical Analyses

Before performing statistical tests, the data were checked for normality and homogeneity of variances, and we excluded outliers by means of box plots. Repeated measures analysis of variance (ANOVA) followed by post-hoc LSD test compared differences between treatments’ cumulative germination percent of seeds after the 4th, 8th and 12th day after the start of germination and the mass of the seeds at 0, 1, 6 and 24 h of water uptake or water loss. One-way ANOVA followed by post-hoc LSD test compared differences between treatments total seed recovery, mean retention time, morphological characteristics (i.e., seed length, width, height, MCD, coat thickness, and 100-grain weight), viability and total germination percent. The data without a normal distribution were analyzed with a nonparametric test (Kruskal–Wallis test) followed by two sided tests. There was a significant difference between treatments samples with a statistical significance of p < 0.05. Experimental data were analyzed by SPSS 26 and plotted by Origin 2022; the experimental results were expressed as mean ± SE.

3. Results

3.1. Seed Recovery Percent and Mean Retention Time

The daily recovered seeds were counted, and the recovery curves of seeds in the feces of different livestock are shown in Figure 2 (The relevant data are shown in Table S1). The recovery of seeds sourced from feces was mainly concentrated at 24–48 h, and there were significant differences in the recovery percent in feces of different species of livestock (one-way ANOVA, F2,6 = 45.072, p < 0.001). The highest SRP of 54.05% for CS was significantly higher than that of HS (4.83%) and SS (0.45%), considering post-hoc LSD test (p < 0.05). The MRT of seeds in the digestive tracts of different livestock was shown in Figure 3. The MRT of CS, HS and SS was 53 h, 57 h, and 45 h, MRT was significant between different species of livestock, considering the Kruskal–Wallis test (p = 0.038). The MRT of horses was the longest and significantly higher than that of sheep (two sided tests, p = 0.033).

3.2. Seed Traits and Viability

The length, width, height, MCD, seed coat thickness, 100-grain weight, and seed viability of seeds after digestive tract treatment were shown in Table 1 (The relevant data are shown in Tables S2 and S3). The length, width and height of seeds were not significant between different species of livestock after digestive tract effect (one-way ANOVA, F3,35 = 0.738, p = 0.537; F3,34 = 2.457, p = 0.080; F3,34 = 1.494, p = 0.234); but MCD was significant (one-way ANOVA, F3,35 = 3.980, p = 0.015), and only the MCD of SS was significantly decreased (LSD test, p = 0.002). Compared with CK, seed coat thickness and 100-grain weight of seeds after digestive tract effect were significantly reduced (one-way ANOVA, F3,14 = 67.672, p < 0.001; F2,6 = 39.479, p < 0.001), the seed coat thickness of HS was the minimum, which was significantly thinner than that of CS and SS, and the 100-grain weight of HS was significantly lower than that of CS, considering post-hoc LSD test (p < 0.05); the viability of seeds in both CK and CS was 100%, and that of HS was significantly lower considering the Kruskal–Wallis test (p = 0.022); the SS recovery percent was extremely low, so we did not collect enough seeds to determine the 100-grain weight and seed viability.
The seed coat status under the stereomicroscope at 30 times and an electron scanning microscope at 300 times was shown in Figure 4. The surface of the seed coat darkened and showed different degrees of fissures after the seeds through the digestive tract. The seed coat surface of CK was smooth, while SS became a little rough, but the seed coat surface of CS and HS showed serious damage.

3.3. Seed Permeability

Intake and water loss curves of CK, CS, and HS were shown in Figure 5 (The relevant data are shown in Table S4). Seeds showed rapid water uptake or loss at the beginning of both uptake and water loss. The rate of water uptake or loss gradually decreased with time, and were significant between different treatments (ANOVA repeated measures, F2,6 = 17.542, p = 0.003; F2,6 = 38.788, p < 0.001), the rate of water uptake or loss of HS was significantly higher than that of CK (LSD test, p = 0.025; p = 0.003) and CS (LSD test, p = 0.026; p = 0.008).

3.4. Seed Germination

The germination percent of CK, CS, and HS at different cold stratification times are shown in Figure 6 (The relevant data are shown in Tables S5–S7). Seed germination percent differed significantly between treatments with different cold stratification times (ANOVA repeated measures, F2,27 = 24.429, p < 0.001) and between different livestock species (ANOVA repeated measures, F2,27 = 49.191, p < 0.001). At 60 days of seed cold stratification, the initiation time of CK, CS, and HS seed germination were 6 d, 5 d and 11 d, the germination percent of CK was the largest, then was CS, and HS was lowest. At 70 days of cold stratification, the initiation time of CK, CS, and HS seed germination were 4 d, 4 d and 7 d, the germination percent increased significantly than that of 60 days (LSD test, p = 0.023), and the germination percent was still CK > CS > HS. At 80 days of cold stratification, the initiation time of CK, CS, and HS seed germination were 2 d, 2 d, and 5 d, only the total germination percent of CS increased significantly (LSD test, p = 0.008), and it was higher than that of CK. The initiation time of seed germination decreased and the germination percent increased with the increase of seed cold stratification time.

4. Discussion

4.1. Seed Recovery Percent and Mean Retention Time

Endozoochory can affect the composition of forest plant communities by permitting plants from open habitats to settle in forest areas [54]. The long-distance dispersal of seeds through the digestive tract requires enough viable seeds and a sufficiently long retention time in the digestive tract [55]. Different livestock have various chewing intensities of food during the feeding process [21], so the recovery percent of the same seeds after digestive effects by different livestock are varied [25]. The retention time of seeds in the digestive tract of different livestock are varied, due to the existence of variations in the length of the digestive tract of different livestock [56,57]. In this study, the seed recovery percent of CS was much higher than HS and SS (Figure 2). This may be due to differences in the structure of the digestive tract among different species of livestock. Cattle are foregut fermenters (i.e., ruminants), food is chewed and enters the rumen, where it is further reduced in size by the effect of rumen fluid. However, horses are colon fermenters (i.e., non-ruminant), it can only reduce the size of food particles by chewing, so their bit force and chewing frequency are higher than that of cattle [58,59]. This may be the reason that the SRP in HS was much lower than that in CS. The recovery of M. sieversii seeds in sheep feces was extremely low. This supports the previous results of Razanamandranto et al. (2004), who found that the size of the animal’s oral cavity and gut influence the extent of seed destruction by mastication and gut surface abrasion during rumination [60]. The smaller the gut, the more the seeds are in contact with the gut wall, and the more susceptible they are to chemical and mechanical abrasion [60]. Martz and Belyea (1986) found that ruminants must chew food particles to a certain size to pass through the rumen, and that the rumen of cattle could pass through larger food particles than that of sheep [61]. This may be the reason that the number of seeds recovered in cattle feces is much larger than in sheep feces, as M. sieversii seeds are large and may not be able to pass through the rumen after fed by sheep, so many seeds are chewed during regurgitation and only a few seeds “escape”. The MRT of HS is significantly higher than SS, but not significantly different from CS (Figure 3). This supports the result of Neto et al. (1987), who concluded that seeds passed quickly in frugivores with short guts and fast metabolism [62]. The maximum daily distance traveled is 25 km for cattle, 28 km for horses, and 21 km for sheep [63,64], sheep have the shortest MRT, thus the distance of diffusion is much less than that of cattle and horses. In this context, in order to spread M. sieversii seeds more and farther, the sheep grazing should be prohibition during M. sieversii ripening because the recovery of seeds in sheep feces is extremely low and the seeds have the shortest MRT in the digestive tract of sheep.

4.2. Morphological Characteristics of Seeds

Seeds undergo corresponding changes in morphological characteristics under the combined effects of acid erosion and numerous enzymes in the animal’s digestive tract [13,65]. In this study, the MCD of seeds in sheep feces decreased significantly after seeds passed through the digestive tracts among three livestock species (Table 1), and possibly most seeds were larger than the rumen aperture, so only a few small seeds passed through the rumen of sheep, resulting in a significant reduction in the MCD of seeds recovered in the feces [66]. The seed coat thickness and 100-grain weight of all seeds recovered in the feces decreased significantly after digestion. These results were the similar as those of Rubia fruticosa seeds, the seed coat thickness decreased significantly after digestive effects by birds, reptiles, and mammals [67]. Seed coat thickness and 100-grain weight decrease was most significant in the HS (Table 1). Compared with other two livestock species, horses have the highest chewing strength and the lowest pH of digestive fluid [59,68,69], as well as the longest seed retention time in the digestive tract (Figure 3), this could be the cause of the thinnest seed coat thickness and the lowest 100-grain weight in horse feces.

4.3. Impact of Digestive Tract Effects on Seed Germination

The effects of the digestive tract on seed germination can be grouped into three categories: promotion, inhibition, and no effect [70]. The digestive tract promotes germination of seeds with physical dormancy [27], but could be no or inhibiting effect on germination with physiological dormancy, morphological dormancy, morpho-physiological dormancy, or non-dormancy [24]. In this study, the effect of digestive tract on seed germination percent differed among livestock, and seed germination percent increased with time of cold stratification (Figure 6). At 60 days of cold stratification, the germination percent of HS was significantly lower than that of CK and CS (Figure 6a), this might be due to a decrease in seed viability after seeds passed through the horse digestive tract (Table 1). At 70 days of cold stratification, seed germination percent of CK, CS and HS were all significantly higher than that of 60 days, indicating that cold stratification facilitated seed germination. When the cold stratification time reached 80 days, the germination percent of CS increased significantly and was higher than that of the CK (Figure 6c), this may be due to the thinning of the CS seed coat after the effect of the digestive tract (Table 1), the holes appeared on the surface of the seed coat (Figure 4; CS-300) and the increased permeability of the seed coat (Figure 5), so that the seeds could break through the seed coat more easily. The results of this study were not identical to those of Soltani et al. (2018), they found that the germination percent of medium-sized seeds (seed length greater than 5 mm) with the presence of physiological dormancy was promoted after the digestive tract [24], while only the germination of CS was promoted, but HS was inhibited in the present study, which indicated that endozoochorous seed dispersal by different animals had varied effects on the germination of the same plant species. In this context, seed viability and germination percent of HS was significantly lower than that of CK and CS, which indicated a negative effect of horse digestive tract on M. sieversii seeds, therefore, in order to ensure a high germination percent of M. sieversii seeds after endozoochory dispersal, the horse grazing should be prohibited during M. sieversii ripening. In much of the research, it was found that digestive tract effects on seed germination were negative [24], and cold stratification effects on seed germination were positive [71]. Our results showed that the seed germination percent of CS after longer cold stratification was similar to that of CK, and the positive effect caused by cold stratification seemed to compensate for the negative effect caused by the effects of the digestive tract, future research is needed to explore the effects of digestive tract and cold stratification on germination of seeds with physiological dormancy.

5. Conclusions

In this study, we found there were significant differences in morphology and germination of seeds after passing through the digestive tracts of three livestock species. Seed recovery and germination percent were highest in cattle feces and significantly higher than those in horse feces and sheep feces, so the quality of seed treatment by cattle is better than by the other species. Based on the results of this study, we identify cattle as more effective dispersers for M. sieversii seed dispersal than horses or sheep. Although livestock grazing under the forest can reduce competition between weeds and M. sieversii trees, we suggest that local forestry management department allow cattle grazing instead of horses and sheep during the fruiting season in the wild fruit forest to facilitate long-distance seed dispersal of M. sieversii. In order to get a complete picture of the role of livestock on M. sieversii dispersal, future studies could explore the physical and chemical characteristics of livestock feces and the environmental of sites where seeds are dispersed on seed germination and seeding establishment, and consequently help assessing their role as seed dispersers for biodiversity conservation and ecosystem function maintenance.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/su142113930/s1, Table S1. Cumulative daily number of seeds recovered by livestock after feeding seeds. Table S2. Seed length, width, height and mean cubic diameter. Table S3. Seed coat thickness, 100-grain weight and viability. Table S4. Water uptake and water loss of CK, CS, HS as a function of time (g). Table S5. Cumulative daily germination number of seeds after 60 days of cold stratification. Table S6. Cumulative daily germination number of seeds after 70 days of cold stratification. Table S7. Cumulative daily germination number of seeds after 80 days of cold stratification.

Author Contributions

Conceptualization, X.S. and D.T.; methodology, J.X. and X.S.; investigation, J.X., Z.Z., S.B. and Y.L.; data curation, J.X. and Z.Z.; writing—original draft preparation, J.X. and X.S.; writing—review and editing, J.X. and X.S.; visualization, J.X. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the National Natural Science Foundation of China, grant number 31960229 and Natural Science Foundation of Xinjiang Uygur Autonomous Region of China, grant number 2017D01B17.

Institutional Review Board Statement

All experimental procedures involving animals were approved by the Animal Welfare and Ethics Committee of Xinjiang Agricultural University, Urumqi, Xinjiang, China (30 December 2021).

Informed Consent Statement

Not applicable.

Data Availability Statement

Data will be provided upon request.

Acknowledgments

Thanks to all the staff of the Ili Botanical Garden, Xinjiang, for their support and help in our work. In addition, we would like to thank three anonymous reviewers for their valuable revision comments.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Karimi, S.; Hemami, M.R.; Tarkesh Esfahani, M.; Akhani, H.; Baltzinger, C. Complementary endozoochorous seed dispersal by large mammals in the Golestan National Park, Iran. Seed Sci. Res. 2018, 28, 294–302. [Google Scholar] [CrossRef]
  2. Pellerin, M.; Picard, M.; Saïd, S.; Baubet, E.; Baltzinger, C. Complementary endozoochorous long-distance seed dispersal by three native herbivorous ungulates in Europe. Basic Appl. Ecol. 2016, 17, 321–332. [Google Scholar] [CrossRef]
  3. Janzen, D.H. Herbivores and the number of tree species in tropical forests. Am. Nat. 1970, 104, 501–528. [Google Scholar] [CrossRef]
  4. Willson, M.F.; Traveset, A. The ecology of seed dispersal. In Seeds: The Ecology of Regeneration in Plant Communities; CABI Pub.: Wallingford, UK, 2014; pp. 62–93. [Google Scholar] [CrossRef]
  5. Wang, B.C.; Smith, T.B. Closing the seed dispersal loop. Trends Ecol. Evol. 2002, 17, 379–386. [Google Scholar] [CrossRef]
  6. Li, H.J.; Zhang, Z.B. Relationship between animals and plant regeneration by seed II. Seed predation, dispersal and burial by animals and relationship between animals and seedling establishment. Biodivers. Sci. 2001, 9, 25–37. [Google Scholar] [CrossRef]
  7. Weduwen, D.; Ruxton, G.D. Secondary dispersal mechanisms of winged seeds: A review. Biol. Rev. 2019, 94, 1830–1838. [Google Scholar] [CrossRef]
  8. Kowarik, I.; Säumel, I. Water dispersal as an additional pathway to invasions by the primarily wind-dispersed tree Ailanthus Altissima. Plant Ecol. 2008, 198, 241–252. [Google Scholar] [CrossRef]
  9. Couvreur, M.; Cosyns, E.; Hermy, M.; Hoffmann, M. Complementarity of epi-and endozoochory of plant seeds by free ranging donkeys. Ecography 2005, 28, 37–48. [Google Scholar] [CrossRef]
  10. Wheelwright, N.T.; Orians, G.H. Seed dispersal by animals: Contrasts with pollen dispersal, problems of terminology, and constraints on coevolution. Am. Nat. 1982, 119, 402–413. [Google Scholar] [CrossRef]
  11. Mouissie, A.M.; Lengkeek, W.; Van Diggelen, R. Estimating adhesive seed-dispersal distances: Field experiments and correlated random walks. Funct. Ecol. 2005, 19, 478–486. [Google Scholar] [CrossRef]
  12. Casper, B.B.; Heard, S.B.; Apanius, V. Ecological correlates of single-seededness in a woody tropical flora. Oecologia 1992, 90, 212–217. [Google Scholar] [CrossRef] [PubMed]
  13. Traveset, A.; Robertson, A.W.; Rodríguez-Pérez, J. A review on the role of endozoochory in seed germination. In Seed Dispersal: Theory and Its Application in a Changing World; CABI Pub.: Wallingford, UK, 2007; pp. 78–103. [Google Scholar] [CrossRef]
  14. Charalambidou, I.; Santamaria, L.; Langevoord, O. Effect of ingestion by five avian dispersers on the retention time, retrieval and germination of Ruppia maritima seeds. Funct. Ecol. 2003, 17, 747–753. [Google Scholar] [CrossRef]
  15. Ridley, H.N. The dispersal of plants throughout the world. J. Ecol. 1930, 19, 215–216. [Google Scholar] [CrossRef]
  16. Chen, Y.; Wang, Z.; Xiang, Z.F. Seed dispersal by primates. Biodivers. Sci. 2017, 25, 325–331. [Google Scholar] [CrossRef] [Green Version]
  17. Zwolak, R.; Sih, A. Animal personalities and seed dispersal: A conceptual review. Funct. Ecol. 2020, 34, 1294–1310. [Google Scholar] [CrossRef]
  18. Li, N.; Zhong, M.; Leng, X.; Wang, A.; Fang, S.B.; An, S.Q. Seed dispersal effectiveness of plant by frugivores: A review. Chin. J. Ecol. 2015, 34, 2041–2047. [Google Scholar] [CrossRef]
  19. Willms, W.D.; Acharya, S.N.; Rode, L.M. Feasibility of using cattle to disperse cicer milkvetch (Astragalus cicer L.) seed in pastures. Can. J. Anim. Sci. 1995, 75, 173–175. [Google Scholar] [CrossRef] [Green Version]
  20. Stroh, P.A.; Mountford, J.O.; Hughes, F.M.R. The potential for endozoochorous dispersal of temperate fen plant species by free-roaming horses. Appl. Veg. Sci. 2012, 15, 359–368. [Google Scholar] [CrossRef]
  21. Oveisi, M.; Ojaghi, A.; Rahimian Mashhadi, H.; Müller-Schärer, H.; Reza Yazdi, K.; Pourmorad Kaleibar, B.; Soltani, E. Potential for endozoochorous seed dispersal by sheep and goats: Risk of weed seed transport via animal faeces. Weed Res. 2021, 61, 1–12. [Google Scholar] [CrossRef]
  22. Sengupta, A. Animal-mediated Seed dispersal in India: Implications for conservation of India’s biodiversity. Biotropica 2021, btp.12982. [Google Scholar] [CrossRef]
  23. Abbas, A.M.; Mahfouz, L.; Ahmed, M.K.; Al-Kahtani, M.A.; Ruxton, G.D.; Lambert, A.M. Effects of seed passage by sheep on germination of the invasive Prosopis juliflora tree. Small Rumin. Res. 2020, 188, 106098. [Google Scholar] [CrossRef]
  24. Soltani, E.; Baskin, C.C.; Baskin, J.M.; Heshmati, S.; Mirfazeli, M.S. A meta-analysis of the effects of frugivory (endozoochory) on seed germination: Role of seed size and kind of dormancy. Plant Ecol. 2018, 219, 1283–1294. [Google Scholar] [CrossRef]
  25. Egea, Á.V.; Campagna, M.S.; Cona, M.I.; Sartor, C.; Campos, C.M. Experimental assessment of endozoochorous dispersal of Prosopis Flexuosa seeds by domestic ungulates. Appl. Veg. Sci. 2022, 25, e12651. [Google Scholar] [CrossRef]
  26. Wang, S.L.; Peng, F.; Lu, W.H.; Chen, Y.S.; Jing, P.C. Seed Morphology and Effects of Sheep Rumen Digestion on Seed Germination of 28 Gramineae Plants. Chin. J. Appl. Ecol. 2017, 28, 3908–3916. [Google Scholar] [CrossRef]
  27. Illescas-Gallegos, E.; Rodríguez-Trejo, D.A.; Villanueva-Morales, A.; Borja-de La Rosa, M.A.; Ordóñez-Candelaria, V.R.; Ortega-Aragón, L.A. Factors influencing physical dormancy and its elimination in two legumes. Rev. Chapingo Ser. Cienc. For. Am. 2021, 27, 413–429. [Google Scholar] [CrossRef]
  28. Baltzinger, C.; Karimi, S.; Shukla, U. Plants on the move: Hitch-hiking with ungulates distributes diaspores across landscapes. Front. Ecol. Evol. 2019, 7, 38. [Google Scholar] [CrossRef] [Green Version]
  29. Albert, A.; Auffret, A.G.; Cosyns, E.; Cousins, S.A.O.; D’hondt, B.; Eichberg, C.; Eycott, A.E.; Heinken, T.; Hoffmann, M.; Jaroszewicz, B.; et al. Seed dispersal by ungulates as an ecological filter: A trait-based meta-analysis. Oikos 2015, 124, 1109–1120. [Google Scholar] [CrossRef]
  30. Smýkal, P.; Vernoud, V.; Blair, M.W.; Soukup, A.; Thompson, R.D. The role of the testa during development and in establishment of dormancy of the legume seed. Front. Plant Sci. 2014, 5, 351. [Google Scholar] [CrossRef]
  31. Hofmann, R.R. Evolutionary steps of ecophysiological adaptation and dive351rsification of ruminants: A comparative view of their digestive system. Oecologia 2004, 78, 443–457. [Google Scholar] [CrossRef]
  32. Anderson, T.M.; Schütz, M.; Risch, A.C. Endozoochorous seed dispersal and germination strategies of serengeti plants. J. Veg. Sci. 2014, 25, 636–647. [Google Scholar] [CrossRef]
  33. Hsin-shi, C. On the eco-geographical characters and the problems of classification of the wild fruit-tree forest in the ili valley of sinkiang. J. Integr. Plant Biol. 1973, 15, 239–253. [Google Scholar]
  34. Chen, X.; Feng, T.; Zhang, Y.; He, T.; Feng, J.; Zhang, C. Genetic diversity of volatile components in Xinjiang wild apple (Malus sieversii). J. Genet. Genom. 2007, 34, 171–179. [Google Scholar] [CrossRef]
  35. Tian, Z.; Song, H.; Wang, Y.; Li, J.; Maimaiti, M.; Liu, Z.; Zhang, H.; Zhang, J. Wild apples are not that wild: Conservation status and potential threats of Malus sieversii in the mountains of Central Asia biodiversity hotspot. Diversity 2022, 14, 489. [Google Scholar] [CrossRef]
  36. Liu, Z.Q.; Chen, W.M.; Xu, Z.; Liang, Q.L. Malus sieversii forest distribution and Agrilus mali Matsumura status of damage in the west part of Tianshan mountains. North. Hortic. 2014, 17, 121–124. [Google Scholar]
  37. Fang, Z.Y.; Li, L.Y.; Maola, A.K.E.; Zhou, L.; Lu, B. Effects of human disturbance on plant diversity of wild fruit forests in western Tianshan mountain. Bull. Soil Water Conserv. 2019, 39, 267–374. [Google Scholar] [CrossRef]
  38. Archetti, M. Evidence from the domestication of apple for the maintenance of autumn colours by coevolution. Proc. R. Soc. B. 2009, 276, 2575–2580. [Google Scholar] [CrossRef] [Green Version]
  39. IUCN. Malus Sieversii: Participants of the FFI/IUCN SSC Central Asian Regional Tree Red Listing Workshop, Bishkek, Kyrgyzstan (11–13 July 2006): The IUCN Red List of Threatened Species 2007: E.T32363A9693009; International Union for Conservation of Nature: Gland, Switzerland, 2007. [Google Scholar]
  40. Genes, L.; Dirzo, R. Restoration of plant-animal interactions in terrestrial ecosystems. Biol. Conserv. 2022, 265, 109393. [Google Scholar] [CrossRef]
  41. Goheen, J.R.; Palmer, T.M.; Keesing, F.; Riginos, C.; Young, T.P. Large herbivores facilitate savanna tree establishment via diverse and indirect pathways. J. Anim. Ecol. 2010, 79, 372–382. [Google Scholar] [CrossRef]
  42. Andresen, E. Effects of dung presence, dung amount and secondary dispersal by dung beetles on the fate of Micropholis guyanensis (Sapotaceae) seeds in Central Amazonia. J. Trop. Ecol. 2001, 17, 61–78. [Google Scholar] [CrossRef] [Green Version]
  43. Xu, Y.; Chen, Y.; Li, W.; Sun, H.; Chen, Y. Analysis on the Spermatophyte Floras in Ili River Valley of China. Arid. Zone Res. 2010, 27, 331–337. [Google Scholar] [CrossRef]
  44. Jia, J.; Xia, D.; Wang, B.; Wei, H.; Liu, X. Magnetic investigation of late quaternary loess deposition, Ili area, China. Quat. Int. 2011, 250, 84–92. [Google Scholar] [CrossRef]
  45. Liu, H.; Zang, R.; Ding, Y.; Zhang, W.; Guo, Z.; Bai, Z.; Liu, S. Population Characteristics of Malus Sieversii in the West Part of Tianshan Mountains, Xinjiang. Sci. Silvae Sin. 2010, 46, 1–7. [Google Scholar] [CrossRef]
  46. Liu, L.; Pai, Z.; Xu, H. Characteristics and systematic classification of soil formation under wild fruit forests in Ili Valley. Arid. Land Geogr. 1997, 34–40. [Google Scholar] [CrossRef]
  47. Lambert, J.E. Digestive retention times in forest guenons (Cercopithecus Spp.) with reference to Chimpanzees (Pan troglodytes). Int. J. Primatol. 2002, 23, 1169–1185. [Google Scholar] [CrossRef]
  48. Traveset, A.; Rodríguez-Pérez, J.; Pías, B. Seed trait changes in dispersers’ guts and consequences for germination and seedling growth. Ecology 2008, 89, 95–106. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  49. Otani, T.; Shibata, E. Seed dispersal and predation by Yakushima macaques, Macaca Fuscata Yakui, in a warm temperate forest of Yakushima Island, southern Japan. Ecol. Res. 2000, 15, 133–144. [Google Scholar] [CrossRef]
  50. Jaya Rathi, J.; Sasirekha, R.; Ranjith Kumar, R. Effect of physical and chemical treatments on breaking the seed dormancy of Caesalpinia bonduc (L.) Roxb. Plant Sci. Today 2021, 8, 572–577. [Google Scholar] [CrossRef]
  51. Baskin, C.C.; Baskin, J.M. Seeds: Ecology, Biogeography, and Evolution of Dormancy and Germination, 2nd ed.; Elsevier/AP: San Diego, CA, USA, 2014; ISBN 978-0-12-416677-6. [Google Scholar]
  52. Liu, Z.Q.; Dong, H.G.; Yu, T.; Chen, W.M. Study on the germination characteristics of Malus sieversii seeds and the field transplanting of seedlings of different seedling ages. J. Anhui Agric. Sci. 2021, 49, 54–56. [Google Scholar] [CrossRef]
  53. Milberg, P.; Andersson, L. Does cold stratification level out differences in seed germinability between populations? Plant Ecol. 1998, 134, 225–234. [Google Scholar] [CrossRef]
  54. Picard, M.; Chevalier, R.; Barrier, R.; Boscardin, Y.; Baltzinger, C. Functional traits of seeds dispersed through endozoochory by native forest ungulates. J. Veg. Sci. 2016, 27, 987–998. [Google Scholar] [CrossRef]
  55. Thomson, F.J.; Moles, A.T.; Auld, T.D.; Kingsford, R.T. Seed dispersal distance is more strongly correlated with plant height than with seed mass. J. Ecol. 2011, 99, 1299–1307. [Google Scholar] [CrossRef]
  56. Agrawal, A.R.; Karim, S.A.; Kumar, R.; Sahoo, A.; John, P.J. Sheep and goat production: Basic differences, impact on climate and molecular tools for rumen microbiome study. Int. J. Curr. Microbiol. Appl. Sci. 2014, 3, 684–706. [Google Scholar]
  57. Tsiplakou, E.; Hadjigeorgiou, I.; Sotirakoglou, K.; Zervas, G. Differences in mean retention time of sheep and goats under controlled feeding practices. Small Rumin. Res. 2011, 95, 48–53. [Google Scholar] [CrossRef]
  58. Hongo, A.; Akimoto, M. The role of incisors in selective grazing by cattle and horses. J. Agric. Sci. 2003, 140, 469–477. [Google Scholar] [CrossRef]
  59. Janis, C.M.; Constable, E.C.; Houpt, K.A.; Streich, W.J.; Clauss, M. Comparative ingestive mastication in domestic horses and cattle: A pilot investigation: Chewing in horses and cattle. J. Anim. Physiol. Anim. Nutr. 2010, 94, e402–e409. [Google Scholar] [CrossRef]
  60. Razanamandranto, S.; Tigabu, M.; Neya, S.; Odén, P.C. Effects of gut treatment on recovery and germinability of bovine and ovine ingested seeds of four woody species from the Sudanian savanna in West Africa. Flora 2004, 199, 389–397. [Google Scholar] [CrossRef]
  61. Martz, F.A.; Belyea, R.L. Role of particle size and forage quality in digestion and passage by cattle and sheep. J. Dairy Sci. 1986, 69, 1996–2008. [Google Scholar] [CrossRef]
  62. Neto, M.S.; Jones, R.M.; Ratcliff, D. Recovery of Pasture Seed Ingested by Ruminants. 1. Seed of Six Tropical Pasture Species Fed to Cattle, Sheep and Goats. Aust. J. Exp. Agric. 1987, 27, 239. [Google Scholar] [CrossRef]
  63. Schlecht, E.; Hiernaux, P.; Kadaouré, I.; Hülsebusch, C.; Mahler, F. A Spatio-temporal analysis of forage availability and grazing and excretion behaviour of herded and free grazing cattle, sheep and goats in Western Niger. Agric. Ecosyst. Environ. 2006, 113, 226–242. [Google Scholar] [CrossRef]
  64. Wallace, Z.P.; Nielson, R.M.; Stahlecker, D.W.; DiDonato, G.T.; Ruehmann, M.B.; Cole, J. An abundance estimate of free-roaming horses on the navajo nation. Rangel. Ecol. Manag. 2021, 74, 100–109. [Google Scholar] [CrossRef]
  65. Yu, X.; Xu, C.; Wang, F.; Shang, Z.; Long, R. Recovery and Germinability of Seeds Ingested by Yaks and Tibetan Sheep Could Have Important Effects on the Population Dynamics of Alpine Meadow Plants on the Qinghai-Tibetan Plateau. Rangel. J. 2012, 34, 249. [Google Scholar] [CrossRef]
  66. Gokbulak, F. Recovery and germination of grass seeds ingested by cattle. OnLine J. Biol. Sci. 2006, 6, 23–27. [Google Scholar] [CrossRef] [Green Version]
  67. Nogales, M.; Nieves, C.; Illera, J.C.; Padilla, D.P.; Traveset, A. Effect of native and alien vertebrate frugivores on seed viability and germination patterns of Rubia fruticosa (Rubiaceae) in the eastern Canary Islands. Funct. Ecol. 2005, 19, 429–436. [Google Scholar] [CrossRef]
  68. Murray, M.J.; Schusser, G.F. Measurement of 24-h gastric pH using an indwelling pH electrode in horses unfed, fed and treated with ranitidine. Equine Vet. J. 1993, 25, 417–421. [Google Scholar] [CrossRef]
  69. Dijkstra, J.; Forbes, J.M.; France, J. Quantitative Aspects of Ruminant Digestion and Metabolism; CABI Pub.: Cambridge, UK, 2005; ISBN 9780851998145. [Google Scholar]
  70. Traveset, A. Effect of seed passage through vertebrate frugivores’ guts on germination: A review. Perspect. Plant Ecol. Evol. Syst. 1998, 1, 151–190. [Google Scholar] [CrossRef] [Green Version]
  71. Cavieres, L.A.; Sierra-Almeida, A. Assessing the importance of cold-stratification for seed germination in alpine plant species of the High-Andes of Central Chile. Perspect. Plant Ecol. Evol. Syst. 2018, 30, 125–131. [Google Scholar] [CrossRef]
Sustainability 14 13930 g001 550
Figure 1. Malus sieversii are consumed by cattle (A), horse (B), and sheep (C), and seeds were found in their feces. The red arrow points to the seeds in the feces.
Figure 1. Malus sieversii are consumed by cattle (A), horse (B), and sheep (C), and seeds were found in their feces. The red arrow points to the seeds in the feces.
Sustainability 14 13930 g001
Sustainability 14 13930 g002 550
Figure 2. Total recovery of Malus sieversii seeds from the feces of cattle, horses, and sheep as a function of time. Values are mean ± SE (n = 3).
Figure 2. Total recovery of Malus sieversii seeds from the feces of cattle, horses, and sheep as a function of time. Values are mean ± SE (n = 3).
Sustainability 14 13930 g002
Sustainability 14 13930 g003 550
Figure 3. Mean retention time of seeds in the digestive tract of cattle, horses, and sheep. Values are mean ± SE (n = 3). Different letter indicates significant differences among treatments (two sided tests, p < 0.05).
Figure 3. Mean retention time of seeds in the digestive tract of cattle, horses, and sheep. Values are mean ± SE (n = 3). Different letter indicates significant differences among treatments (two sided tests, p < 0.05).
Sustainability 14 13930 g003
Sustainability 14 13930 g004 550
Figure 4. Seed coat surface of Malus sieversii at 30 times in stereomicroscope and 300 times in scanning electronic microscope. CK-30, CS-30, HS-30 and SS-30 are photographs of control seeds (CK), seeds in cattle feces (CS), seeds in horse feces (HS), and seeds in sheep feces (SS) under a stereomicroscope; CK-300, CS-300, HS-300 and SS-300 are photographs of control seeds (CK), seeds in cattle feces (CS), seeds in horse feces (HS), and seeds in sheep feces (SS) under scanning electronic microscope.
Figure 4. Seed coat surface of Malus sieversii at 30 times in stereomicroscope and 300 times in scanning electronic microscope. CK-30, CS-30, HS-30 and SS-30 are photographs of control seeds (CK), seeds in cattle feces (CS), seeds in horse feces (HS), and seeds in sheep feces (SS) under a stereomicroscope; CK-300, CS-300, HS-300 and SS-300 are photographs of control seeds (CK), seeds in cattle feces (CS), seeds in horse feces (HS), and seeds in sheep feces (SS) under scanning electronic microscope.
Sustainability 14 13930 g004
Sustainability 14 13930 g005 550
Figure 5. Water uptake and water loss of CK, CS, HS as a function of time. CK are the control seeds, CS are seeds in cattle feces and HS are seeds in horse feces. Values are mean ± SE (n = 3).
Figure 5. Water uptake and water loss of CK, CS, HS as a function of time. CK are the control seeds, CS are seeds in cattle feces and HS are seeds in horse feces. Values are mean ± SE (n = 3).
Sustainability 14 13930 g005
Sustainability 14 13930 g006 550
Figure 6. Germination percent of CK (control seeds), CS (seeds in cattle feces), and HS (seeds in horse feces) at different cold stratification times. Values are mean ± SE (n = 4). (a) Cold stratification 60 d; (b) Cold stratification 70 d; (c) Cold stratification 80 d.
Figure 6. Germination percent of CK (control seeds), CS (seeds in cattle feces), and HS (seeds in horse feces) at different cold stratification times. Values are mean ± SE (n = 4). (a) Cold stratification 60 d; (b) Cold stratification 70 d; (c) Cold stratification 80 d.
Sustainability 14 13930 g006
Table
Table 1. Seed characteristics and viability of Malus sieversii after digestive tract effect by three livestock species. Different letters in the same column represent significant differences (LSD test, p < 0.05).
Table 1. Seed characteristics and viability of Malus sieversii after digestive tract effect by three livestock species. Different letters in the same column represent significant differences (LSD test, p < 0.05).
TypeSeed Length (mm)Seed Width (mm)Seed Height (mm)MCD
(mm3)		Seed Coat Thickness (mm)100-Grain Weight (g)Seed Viability (%)
CK 16.342 ± 0.096 a3.695 ± 0.041 a2.362 ± 0.021 a3.828 ± 0.031 a0.136 ± 0.003 a2.444 ± 0.014 a100 ± 0 a
CS 26.119 ± 0.138 a3.567 ± 0.043 a2.383 ± 0.054 a3.767 ± 0.047 a0.092 ± 0.004 b2.237 ± 0.007 b100 ± 0 a
HS 36.260 ± 0.101 a3.720 ± 0.057 a2.356 ± 0.064 a3.770 ± 0.047 a0.072 ± 0.001 c2.136 ± 0.040 c84.4 ± 5.9 b
SS 46.173 ± 0.122 a3.602 ± 0.040 a2.241 ± 0.051 a3.622 ± 0.045 b0.086 ± 0.003 b--
1 CK: control seeds; 2 CS: seeds in cattle feces; 3 HS: seeds in horse feces; 4 SS: seeds in sheep feces.
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Xu, J.; Zhang, Z.; Bai, S.; Lv, Y.; Shi, X.; Tan, D. Recovery and Germination of Malus sieversii (Ledeb.) M. Roem. (Rosaceae) Seeds after Ingestion by Cattle, Horses, and Sheep. Sustainability 2022, 14, 13930. https://doi.org/10.3390/su142113930

AMA Style

Xu J, Zhang Z, Bai S, Lv Y, Shi X, Tan D. Recovery and Germination of Malus sieversii (Ledeb.) M. Roem. (Rosaceae) Seeds after Ingestion by Cattle, Horses, and Sheep. Sustainability. 2022; 14(21):13930. https://doi.org/10.3390/su142113930

Chicago/Turabian Style

Xu, Jiang, Zongfang Zhang, Shilin Bai, Yaya Lv, Xiaojun Shi, and Dunyan Tan. 2022. "Recovery and Germination of Malus sieversii (Ledeb.) M. Roem. (Rosaceae) Seeds after Ingestion by Cattle, Horses, and Sheep" Sustainability 14, no. 21: 13930. https://doi.org/10.3390/su142113930

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop