Search Results (245)

Although cytoplasmic male sterility (CMS) is well established in eggplant, CMS-based interspecific hybrids with allied species have not yet been reported or studied. In this study, five previously developed CMS-based interspecific F₁ hybrids between eggplant and Solanum aethiopicum Group Aculeatum (=S. integrifolium) and Group Gilo (=S. gilo), together with their parental lines, were morphologically evaluated for 67 seedling, vegetative, floral, and fruit traits, and their heterosis for vegetative growth was studied. Male fertility was assessed based on anther morphology and pollen viability, while female fertility was evaluated through backcrosses to both parents. The hybrids exhibited predominantly intermediate phenotypes and clustered distinctly from parental lines as confirmed by principal component analysis. Remarkable heterosis was observed for most growth-related traits, indicating favorable nuclear–cytoplasmic interactions despite the use of CMS eggplant lines as maternal parents. All hybrids showed complete male sterility, characterized by non-viable pollen and pronounced anther homeotic alterations, the latter indicating CMS-related effects on male fertility. Female fertility was severely reduced, likely due to meiotic irregularities, as evidenced by the failure of most attempted backcrosses. However, successful recovery of BC₁ progeny after backcrossing one CMS-based F₁ hybrid to S. gilo demonstrates partial reproductive compatibility and provides a genetic bridge for CMS introgression into S. gilo. These results indicate that CMS systems are suitable for eggplant interspecific crosses aimed at vigorous rootstock production and CMS cytoplasm introgression into allied germplasm. Full article

The large and hard olive pit adversely affects oil quality during traditional crushing, as seed- and pit-derived enzymes modify phenolic profiles and volatile compounds. Polyploid breeding offers a potential means to reduce pit size and improve processing traits, yet cultivated olive (Olea europaea L. subsp. europaea) is a strictly diploid species, and natural polyploids have not been previously documented. To evaluate the potential of triploids in olive improvement, we screened seed-derived progeny from multiple cultivars for polyploidy using flow cytometry and chromosome observation. One naturally occurring triploid seedling (‘Olive-3x’) was identified from a mixed lot of open-pollinated seeds. Whole-genome resequencing was used to develop 64 polymorphic InDel markers, and three markers indicated ‘Koroneiki’ as one putative parent of the triploid. Morphological and cytological analyses showed that the triploid exhibited typical polyploid characteristics, including thicker leaves and enlarged epidermal and palisade mesophyll cells compared with diploid controls. These findings provide the first evidence of a naturally occurring triploid in cultivated olive and show that triploids can arise within seed-derived progeny. The identified triploid plant and the developed markers offer useful resources for future studies on olive polyploidy and provide foundational resources for future research on olive polyploidy and cultivar improvement. Full article

Polyploidization is a powerful tool in plant breeding that can induce desirable morphological and physiological modifications. This study aimed to establish an efficient in vitro protocol for inducing autotetraploid plants in cherimoya (Annona cherimola Mill. cv. Fino de Jete) using colchicine. Hypocotyl explants from seedlings germinated in vitro were treated with different colchicine concentrations (0.01–0.2%) for 24 and 48 h, and the effects on shoot regeneration and ploidy level were evaluated by flow cytometry and chromosome counting. Regeneration and survival rates decreased with increasing colchicine concentration and exposure time. The most effective treatment for autotetraploid induction was 0.1% colchicine for 24 h, yielding a 10.5% polyploidization rate with 5.8% autotetraploids. Tetraploid shoots were successfully rooted (80%) and acclimatized (100%) under greenhouse conditions. Autotetraploid plants exhibited significantly larger and more rounded leaves, higher chlorophyll contents and an increased Chl a/Chl b ratio compared with diploids, indicating enhanced photosynthetic efficiency. The induction of stable autotetraploid lines in A. cherimola provides a reliable approach for generating novel genotypes with improved physiological traits and potential tolerance to abiotic stress. These results offer valuable material for future breeding programs aimed at developing new cherimoya rootstocks and cultivars with enhanced vigor and adaptability. Full article

Early post-germination physiological responses determine oak seedling establishment success under changing environmental conditions. This study investigated four oak species (Quercus cerris, Q. frainetto, Q. petraea, and Q. pubescens) through direct seeding experiments across four locations in Serbia representing varying habitat conditions. Physiological parameters (quantum yield of photosystem II, total stomatal conductance, and leaf vapor pressure deficit) were measured intensively during the first growing season, along with morphological traits and survival rates. Results revealed that microclimatic and soil conditions exerted stronger effects on seedling physiology than species identity, with air humidity, temperature, and soil moisture being primary drivers of photosynthetic performance. Surviving seedlings exhibited 18% higher PhiPSII and 128% higher stomatal conductance compared to non-survivors, demonstrating that physiological performance is a reliable predictor of establishment success. Species-specific differences were evident. Q. cerris and Q. frainetto maintained the highest photosynthetic activity across sites, Q. pubescens showed intermediate resilience, and Q. petraea displayed greater sensitivity to environmental stress. These findings highlight the dominant role of microsite conditions in shaping early seedling physiology and survival. Physiological measurements, particularly PhiPSII and gtw, provide useful early indicators of establishment success during the first growing season following direct seeding. Full article

The sustainable cultivation of Moringa oleifera is constrained by limited availability of high-quality planting materials. This study established an integrated propagation framework combining seed, cutting, and air-layering methods for the rapid and reliable multiplication of superior genotypes with good morphological traits and elevated astragalin content. Seed pretreatment trials showed that simple soaking for 12 h significantly reduced mean germination time without affecting final germination percentage, while a topsoil–cocopeat–compost mixture enhanced early seedling survival and growth. HPLC profiling identified four genotypes with significantly higher astragalin concentrations (187–281 ppm), linking phytochemical quality with propagation performance. Vegetative propagation experiments revealed that cutting position and girth strongly influenced regeneration success. Cutting position experiments showed clear positional differences, with basal cuttings achieving the highest rooting response. Bottom cuttings produced the highest number of shoots (4.22), nodes (5.00), and thickest shoots (24.65 mm), as well as the highest rooting percentage. Middle cuttings developed the longest shoots (40.21 cm) and the greatest number of roots (32.83), with a rooting percentage of 66.70%. Top cuttings showed the lowest performance across all shoot and root traits. Larger-diameter cuttings produced more shoots but fewer roots while smaller-diameter cuttings produced more roots but fewer shoots. Air-layering with Jiffy-7 pellets achieved the highest root number (43.83) and length (7.23 cm), with 100% survival. Overall, the study provides a robust, mechanism-supported propagation strategy that enables large-scale, uniform production of superior Moringa genotypes, strengthening future programs in clonal improvement, genetic conservation, and sustainable agroforestry development. Full article

Intensive irrigated agriculture relies heavily on nitrogen fertilization, which may cause ammonium accumulation, highly detrimental to sensitive seedlings. Silicon application has emerged as a potential strategy to mitigate this stress, although the underlying mechanisms remain poorly understood. To evaluate this effect, maize seedlings were grown in nutrient solution under five N concentrations (1.4, 3.6, 7.1, 14.3, and 28.6 mmol L⁻¹), applied in the presence or absence of silicon (1.8 mmol L⁻¹ Si). The nitrogen source was a mixture of nitrate and ammonium in a N-NO₃⁻: N-NH₄⁺ ratio of 4:5. Silicon was supplied as monosilicic acid (H₂SiO₃). Plant growth, leaf area, root morphology (length, diameter, density), N and Si accumulation, uptake and utilization efficiency, SPAD index, nitrate reductase activity, and proline content were evaluated. Silicon supplementation enhanced nitrate reductase activity, SPAD values, leaf area, and root traits, reduced proline in roots and shoots, and improved N uptake and partitioning. Among the tested N concentrations, 14.3 mmol L⁻¹ achieved the highest efficiency of nutrient absorption and biomass production, highlighting silicon as a sustainable strategy to mitigate ammonium stress in maize seedlings. Full article

Prolonged low-light stress during growth significantly reduces rice yield in southwest China. In order to systematically study the dynamic response of rice to long-term shading, field experiments were conducted in Chongqing, China, from 2021 to 2022, investigating the effects of 50% and 75% shading from the seedling to heading stage on morphological characteristics, physiological traits, and yield formation in 12 rice cultivars. The results showed that shading reduced tiller number, leaf mass per area, total dry mass, leaf area index, panicle number, seed-setting rate, and yield. Meanwhile, rice acclimated to low light by increasing plant height, leaf chlorophyll content, and leaf-total mass ratio. In particular, leaf width in low-light treatments was narrower under short-term shading but became wider under long-term shading compared to natural light. Moreover, under 50% shading condition, rice optimized panicle structure by increasing grain number per panicle and primary and secondary branch numbers to compensate for adverse effects. Cultivars, including Le you 918 and Shen 9 you 28, exhibited high yield and strong shade tolerance. Overall, rice acclimates to low light through the synergistic interactions of various traits, with leaf phenotypic adjustments and panicle structure optimization being crucial for improving yield under low light. Full article

Water stress is among the most important abiotic constraints affecting forest ecosystem functioning and regeneration, a phenomenon expected to intensify with climate change. It impacts photosynthesis, growth, and seedling survival, therefore threatening biodiversity and accelerating forest degradation. The use of silicon-based biostimulants has emerged as a way of mitigating the effects of water stress by improving water status and stimulating mechanical and biochemical defense. However, its effectiveness on forest tree species remains poorly explored. This study examines how potassium silicate (PS) alleviates the effects of drought on Canarium madagascariense, with the aim of improving our understanding of the resilience mechanisms of tropical forest species. To do this, an experiment with 135 two-year-old C. madagascariense saplings has been conducted, testing three irrigation levels in combination with the addition of potassium silicate (PS) at concentrations of 5 and 10 mM, via foliar spraying and soil application. Morphometric and physiological parameters were monitored, followed by the biochemical profiling of the induced responses. Linear mixed models were computed to assess the effects of the different factors on the different growth performance, physiological functioning parameters over time, and ANOVA was used for evaluating the punctual data on the biochemical compounds. Drought had a significant impact on the morphological and physiological behaviour of the seedlings. However, the application of PS modified the drought-induced changes, even at a low concentration of 5 mM. Biochemical defenses were also improved further with PS application. Hormone profiling revealed a predominance of auxins, while abscisic acid was lower in the water stress treatments under drought. Therefore, using PS could support the production of robust seedlings that are more tolerant of, and adaptive to, the challenges of climate change, making restoration more efficient. Full article

Cymbidium faberi Rolfe is a Chinese flower famous due to its beautiful floral pattern and strong floral scent and is also a threatened terrestrial orchid. Moreover, the traditional propagation method through tillers and symbiotic seed germination with the correct fungus under nature conditions could not meet conservation and commercial needs. Here, an efficient procedure for asymbiotic seed germination and in vitro seedlings development of C. faberi was successfully established through evaluation of time of seed collecting, seed pretreatments, light conditions and composition of culture media, respectively. Seed pretreatment with 1% NaClO for 30 min, dark culture on 1/4 MS medium containing 0.5 mg·L⁻¹ 6-BA and 0.1 mg·L⁻¹ NAA for 30 days and subsequent long day condition (14 h light/10 h dark photoperiod) culture on this medium for 30 days could obviously enhance the seed germination rate of C. faberi. The highest germination rate (85.0 ± 0.79%) was achieved when seeds were collected at 120 d after cross-fertilization, and then germination percentages progressively decreased. Furthermore, histological analyses from protocorm formation to seedling growth were explored. This study not only offers a reliable and scalable system for mass propagation to meet commercial and conservation demands but also serves as a foundational reference for physiological and molecular studies in Cymbidium and related orchids. Full article

Global climate change has intensified land desertification in the arid and semi-arid regions of northwestern China, highlighting the urgent need to cultivate plant species with ideal architecture and well-developed root systems to combat ecosystem degradation. Amorpha fruticosa is widely used as a windbreak and sand-fixation shrub; however, its rapid growth and high transpiration during the early planting stage often result in excessive water loss, low survival rates, and limited vegetation restoration effectiveness. Plant growth retardants (PGRts) are known to suppress apical dominance and promote branching. In this study, one-year-old A. fruticosa seedlings were treated with different combinations of paclobutrazol (PP₃₃₃) and uniconazole (S₃₃₀₇) to investigate their effects on plant morphology and biomass allocation; it aims to determine the optimal formula for cultivating shrub structures with excellent windbreak and sand-fixation effects in land desertification areas. The results showed that both PP₃₃₃ and S₃₃₀₇ significantly inhibited plant height while promoting basal stem diameter, branching, and root development. Among all treatments, the S₃₃₀₇ 200 mg·L⁻¹ + PP₃₃₃ 200 mg·L⁻¹ combination (SD3) was the most effective, resulting in the greatest increases in basal diameter, branch number, total root length, and root-to-shoot ratio, while significantly reducing height increment, leaf length and leaf area (p < 0.05). Under the S₃₃₀₇ 200 mg·L⁻¹ + PP₃₃₃ 300 mg·L⁻¹ treatment (SD4), leaf width and specific leaf area were reduced by 17.92% and 38.89%, respectively, compared with the control. Correlation analysis revealed significant positive or negative relationships among most growth traits, with leaf length negatively correlated with other morphological indicators. Fresh and dry weights of both aboveground and root tissues were significantly positively correlated with basal diameter (R = 0.38) and branch basal diameter (R = 0.33). Principal component analysis demonstrated that the SD3 treatment achieved the highest comprehensive score (2.91), indicating its superiority in promoting a compact yet robust plant architecture. Overall, the SD3 treatment improved drought resistance and sand-fixation capacity of A. fruticosa by “dwarfing and strengthening plants while optimizing root–shoot allocation.” These findings provide theoretical support for large-scale cultivation and vegetation restoration in arid and semi-arid regions and offer a technical reference for growth regulation and windbreak and sand-fixation capacity in other xerophytic shrub species. Full article

To improve the mechanized transplanting efficiency for large-scale broccoli production in Ningxia, this study aims to identify key morphological traits of seedlings suitable for mechanized transplanting. A Box–Behnken design was used to set three experimental factors, broccoli variety, seedling age, and plug tray specification, to evaluate their effects on seedling plant type (plant height, stem diameter, canopy diameter, stem inclination angle, and plant type cone angle) and root system characteristics (substrate loss rate). The results showed that plug tray specification was the primary factor affecting substrate loss rate, followed by variety and seedling age. Seedling age was the dominant factor affecting plant height, stem diameter, and canopy diameter, while plug tray specification primarily influenced stem inclination angle. Optimization via response surface methodology (RSM) indicated that the best transplanting performance was achieved with the “Hannai Youxiu” variety (excellent cold tolerance), 30-day-old seedlings, and 72-cell or 98-cell plug trays. Field validation confirmed that under these optimal parameters the mechanized transplanting feeding rate reached 100%, the seedling missing rate was 2.5%, and the transplanting qualification rate was 97.5%, with all RMSE values being less than 7.5%. These findings provide a scientific basis for the mechanized transplanting of broccoli in Ningxia, recommending the “Hannai Youxiu” variety and 98-cell plug trays with 30-day-old seedlings to enhance transplanting quality and production efficiency. Full article

Crateva tapia L. is a native tree species of the Caatinga biome, with medicinal and allelopathic properties. This study aimed to characterize the biometric and morphological traits of fruits, seeds, seedlings, and young plants of C. tapia, as well as to evaluate the germination pattern of its seeds under different temperatures, in order to understand the reproductive strategies and optimal conditions for its propagation. The results are intended to support conservation efforts, ecological restoration, and the sustainable use of the species within the Caatinga biome. The research was carried out at the Seed Analysis Laboratory of the Federal University of Paraíba, Campus II, Areia–PB, Brazil. The biometric data were obtained from 100 fruits and 100 seeds obtained from eight mother plants. The imbibition curve was determined from the weight of the seeds during 216 h at different temperatures, and the germination test was performed concomitantly. The fruits were morphologically described regarding the external and internal aspects of the pericarp. The seeds were described according to their consistency, color, texture, shape, hilum, and embryo. The fruits of C. tapia vary in size, fresh mass, and number of seeds, characterized as amphisarcidium, indehiscent, and polyspermic. The seeds are small, brown, reniform, and biting, with a cotyledonary embryo with a poorly differentiated hypocotyl–radicle axis, with a well-developed hilum and surrounded by a fleshy mesocarp. The germination of C. tapia seeds is epigeal-phanerocotyledonous; the seedlings have white axial roots containing absorbent hairs. Full article

Macadamia (Macadamia spp.), as a high-value cash crop, relies on varietal adaptability screening and quality optimization for enhanced industrial benefits. However, existing research has predominantly focused on the mature tree stage. Systematic studies on the physiological characteristics during the seedling stage and comprehensive multi-indicator evaluations remain insufficient, limiting improved variety selection and industrial development. This study investigated three macadamia varieties (A4, A16, A203). We systematically measured leaf morphology, photosynthetic parameters, antioxidant enzyme activities, and free amino acid content at the seedling stage, combined with a comprehensive analysis of mature fruit morphology, mineral elements, amino acid composition, and pericarp phenolic compounds. The results indicated that at the seedling stage: A4 exhibited the highest SPAD value and CAT activity, significantly exceeding A16 and A203 by 137.14% and 139.82%, respectively, alongside the lowest MDA content, highlighting its superior stress resistance; A16 showed the highest Pn, Cleaf, and WUE, with total amino acid content being 38.09% and 18.79% higher than A4 and A203, respectively; A203 demonstrated the highest light energy utilization efficiency, significantly higher SOD activity compared to A16 and A203, and the lowest O²⁻ content. Regarding fruit quality: A16 kernels contained the highest total amino acids and umami amino acids, with sweet and aromatic amino acids also being significantly higher than in other varieties; A203 performed notably well in K, Mg, and Mn content, with medicinal amino acids accounting for over 70% of the total; A4 pericarp contained significantly higher levels of phenolic compounds, such as p-hydroxybenzoic acid, compared to A16 and A203, some exceeding 80%. Correlation analysis revealed a complex regulatory network among fruit traits, mineral elements, amino acids, and phenolics. In summary, A4, A16, and A203 possess respective advantages in high stress resistance, superior flavor quality, and high nutritional functionality. This study establishes a comprehensive “morphology–photosynthesis–antioxidant activity–amino acids–quality” evaluation system, providing a scientific basis for targeted breeding and whole-industry-chain development of macadamia. Full article

Copper (Cu) and cadmium (Cd) are common co-occurring environmental pollutants inducing combined stress, which severely harms maize growth. Previous studies have confirmed the involvement of the ascorbate–glutathione (AsA-GSH) cycle in heavy metal stress tolerance, but the regulatory effect of NATCA on this cycle under Cu-Cd combined stress—especially during maize seed germination and root development—remains unelucidated. Exogenous folcisteine (NATCA, 3-acetylthiazolidine-4-carboxylic acid) can enhance plant tolerance to abiotic stress. This study investigated the role of NATCA, a novel plant growth regulator with antioxidant potential, in alleviating Cu-Cd combined stress in maize. Two maize (Zea mays L.) varieties—Jiuyuan 15 (Cu/Cd-tolerant) and Longfuyu 6 (Cu/Cd-intolerant)—were exposed to combined stress (80 mg·L⁻¹ CuSO₄ + 100 mg·L⁻¹ CdCl₂) with/without 20 mg·L⁻¹ NATCA. Germination and hydroponic experiments were conducted to investigate NATCA’s effects on seed germination, growth, root traits, photosynthetic characteristics, reactive oxygen species (ROS) metabolism, AsA-GSH cycle (ascorbate–glutathione cycle), and endogenous hormones under stress. The results showed that combined Cu/Cd stress inhibited seed germination (reduced vigor, rate, index), while NATCA significantly reversed these declines, increased tolerance index, lowered relative damage rate, and improved seed activity—with more pronounced effects on Longfuyu 6. Stress stunted seedling growth (reduced dry/fresh weight, water content; increased water deficit), whereas NATCA promoted growth (taller plants, less leaf chlorosis, more fibrous roots), enhanced dry matter accumulation, and improved water metabolism. Stress impaired root morphology (shorter length, smaller surface area/volume, fewer tips) and absorption capacity; NATCA improved root traits, stress tolerance, and vitality. Stress weakened ROS scavenging, but NATCA elevated antioxidant enzyme activity and non-enzymatic antioxidant content, strengthened AsA-GSH cycle-mediated ROS clearance, mitigated stress damage, and maintained intracellular ROS balance in maize seedling root. These findings not only reveal a new regulatory role of NATCA in enhancing heavy metal stress tolerance via the AsA-GSH cycle but also provide a potential eco-friendly strategy for improving maize production in heavy metal-contaminated soils. Full article

Thinopyrum intermedium (c.n. intermediate wheatgrass), marketed under the trade name Kernza, is a promising species for perennial grain production based on seed size, ease of threshing, resistance to shattering, and grain quality. Although numerous generations of breeding for seed yield have been completed, the impact of selection on non-target traits is unknown. Here, we evaluated structural and functional changes brought about by selection for seed yield over a sequence of nine selection cycles (C0 to C9). In two experiments under semi-controlled environmental conditions, we compared gas exchange (A, E, gs, and A/Ci curves), leaf and root morphology, and the structure of seedlings from 10 generations. We found that the selection for yield throughout cycles indirectly changed the leaf structure (leaf size, leaf thickness, and leaf anatomy) and physiology (carbon acquisition and transpiration per unit area), with later cycles showing larger leaves with higher rates of CO₂ assimilation and transpiration. Changes in root structure followed similar trends: selection resulted in longer, more branched, and finer roots. These changes in non-target traits are linked to resource-use strategies and to ecosystem services provided by Kernza. Understanding how the domestication of perennial grains impacts non-target traits will aid in the design of integrated breeding programs for Kernza and other perennial grain crops. Full article