Search Results (71)

Under the scenario of global climate warming, meteorological risks affecting sunflower cultivation in Xinjiang’s 10th Division were investigated by developing a meteorological-growth coupling model. Field experiments were conducted at three representative stations (A1–A3) during 2023–2024 to assess temperature and precipitation impacts on yield and quality traits among sunflower cultivars with varying maturation periods. The main findings were: (1) Early-maturing cultivar B1 (RH3146) exhibited superior adaptation at low-temperature station A1, achieving 12% higher plant height and an 18% yield increase compared to regional averages. (2) At thermally variable station A2 (daily average temperature fluctuation ± 8 °C, precipitation CV = 25%), the late-maturing cultivar B3 showed enhanced stress resilience, achieving 35.6% grain crude fat content (15% greater than mid-maturing B2) along with 8–10% increases in seed setting rate and 100-grain weight. These improvements were potentially due to optimized photoassimilated allocation and activation of stress-responsive genes. (3) At station A3, characterized by high thermal-humidity variability (CV > 15%) during grain filling, B3 experienced a 15-day delay in maturation and a 3% reduction in ripeness. Two principal mitigation strategies are recommended: preferential selection of early-to-mid maturing cultivars in regions with thermal-humidity CV > 10%, improving yield stability by 23%, and optimization of sowing schedules based on accumulated temperature-precipitation modeling, reducing meteorological losses by 15%. These evidence-based recommendations provide critical insights for climate-resilient cultivar selection and precision agricultural management in meteorologically vulnerable agroecosystems. Full article

Over the past few decades, peanut smut, caused by Thecaphora frezzii, has evolved from an emerging disease to a major global threat to peanut production. However, critical knowledge gaps persist regarding the anatomical pathways and host responses involved in infection, colonization, and sporulation. This study examines the pathosystem and histopathology of the biotrophic phase of T. frezzii in the susceptible cv. Granoleico. Anatomical analyses were conducted using light microscopy, confocal laser scanning, and scanning electron microscopy. Our findings reveal that T. frezzii enters the host through the peg rather than the ovary tip, invading during the R2-subterranean phase. Fruit colonization occurs at the R3-stage when the mechanical layer between the mesocarp and endocarp has not yet formed. Hyphal entry into the seed takes place between the R3-medium and R3-late pod stages via the funiculus, leading to extensive seed coat colonization without penetrating the embryo. Once inside, hyperplasia and hypertrophy are triggered, coinciding with teliospore formation. Teliosporogenesis disrupts nutrient translocation, arresting embryo development. The hyphae colonize tissues intracellularly, utilizing living cells of the vascular bundles and following the peanut’s photoassimilate transport pathway. Investigating these structural responses in phenotypically contrasting peanut genotypes may provide key insights into the anatomical barriers and defense mechanisms that determine disease susceptibility and resistance, ultimately contributing to the development of resistant cultivars. Full article

Dioecious species show a division of labor expressed through the differentiated manifestation of resource acquisition. We hypothesized that the expression of secondary sexual dimorphism (SSD) in the leaf gas exchange of yerba mate would be more intensive in females than in males to permit females the carbon investments necessary to finish the reproductive cycle. This species can present two growth units annually (GU1-fall and GU2-spring) intercalated with two rest periods (R1-summer and R2-winter). The leaf area index (LAI) and the diurnal courses of leaf photosynthesis (A_net), stomatal conductance (g_s), leaf transpiration (E), intercellular CO₂ concentration (C_i), water use efficiency (WUE), and instantaneous carboxylation efficiency (A_net/C_i) were estimated in female and male plants of yerba mate during four periods of annual rhythmic growth in monoculture (MO) and agroforestry (AFS). Leaf gas exchanges varied over the annual rhythmic growth and were more intensive under MO than under AFS. A_net, A_net/C_i ratios, and WUE were higher in females than in males during the summer (R1) and spring (GU2). Also, g_s and E were more intensive in females than males during the summer. Oppositely, higher WUE in males than in females was observed during the fall (GU1) and winter (R2), with males also showing a higher A_net/C_i ratio during the winter and higher E during the spring (GU2). Despite the strong effect of the cultivation system on LAI and leaf gas exchange traits over the diurnal course, SSD expression was rarely modified by the cultivation system, being expressed only in MO for E during the spring (GU2) and WUE during the winter (R2). High WUE in males during the winter would benefit plants during cold and dry periods, improving the balance between carbon acquisition and water loss through transpiration. On the other hand, high A_net during the summer and spring could be considered as a general fitness strategy of female plants to improve photoassimilate supply and support their additional reproduction costs. Full article

Heat stress is one of the major concerns for wheat production worldwide. Morphological parameters such as germination, leaf area, shoot, and root growth are affected by heat stress, with affected physiological parameters including photosynthesis, respiration, and water relation. Heat stress also leads to the generation of reactive oxygen species that disrupt the membrane systems of thylakoids, chloroplasts, and the plasma membrane. The deactivation of the photosystems, reduction in photosynthesis, and inactivation of Rubisco affect the production of photo-assimilates and their allocation, consequently resulting in reduced grain yield and quality. The development of thermo-tolerant wheat varieties is the most efficient and fundamental approach for coping with global warming. This review provides a comprehensive overview of various aspects related to heat stress tolerance in wheat, including damages caused by heat stress, mechanisms of heat stress tolerance, genes or QTLs regulating heat stress tolerance, and the methodologies of breeding wheat cultivars with high heat stress tolerance. Such insights are essential for developing thermo-tolerant wheat cultivars with high yield potential in response to an increasingly warmer environment. Full article

The source–sink relationship is critical for proper plant growth and development, particularly for vegetative axillary buds, whose activity shapes the branching pattern and ultimately the plant architecture. Once formed from axillary meristems, axillary buds remain dormant or become active to grow into new branches. This transition is notably driven by the regulation of the bud sink strength, which is reflected in the ability to unload, metabolize and store photoassimilates. Plants have so far developed two main mechanisms for unloading sugars (sucrose) towards sink organs, a symplasmic pathway and an apoplasmic pathway, but so far limited investigations have been reported about the modes of sugar uptake during the transition from the dormant to the active outgrowth state of the bud. The available data indicate that the switch from dormant bud to active outgrowing state, requires sugar and is shortly preceded by an increase in bud metabolic activity and a remobilization of the stem starch reserves in favor of growing buds. This activation of the bud sink strength is accompanied by an up-regulation of the main markers of apoplasmic unloading, such as sugar transporters (sucrose transporters—SUTs; sugar will eventually be exported transporters—SWEETs), sucrose hydrolyzing enzymes (cell wall invertase—CWINV) and sugar metabolic pathways (glycolysis/tricarboxylic cycle—TCA; oxidative pentose phosphate pathway—OPPP). As these results are limited to a few species, they are not sufficient to provide a complete and accurate picture of the mode(s) of sugar unloading toward axillary buds and deserve to be complemented by additional studies in a wide variety of plants using systems integration, combining genetic, molecular and immunolocalization approaches. Altogether, we discuss here how sugar is a systemic regulator of shoot branching, acting both as an energy-rich molecule and a signaling entity in the establishment of the bud sink strength. Full article

Recent studies actively debate oxic methane (CH₄) production processes in water and terrestrial ecosystems. This previously unknown source of CH₄ on a regional and global scale has the potential to alter our understanding of climate-driving processes in vulnerable ecosystems, particularly high-latitude ecosystems. Thus, the main objective of this study is to use the incubation approach to explore possible greenhouse gas (GHG) fluxes by the most widely distributed species of epiphytic lichens (ELs; Evernia mesomorpha Nyl. and Bryoria simplicior (Vain.) Brodo et D. Hawksw.) in the permafrost zone of Central Siberia. We observed CH₄ production by hydrated (50%–400% of thallus water content) ELs during 2 h incubation under illumination. Moreover, in agreement with other studies, we found evidence that oxic CH₄ production by Els is linked to the CO₂ photoassimilation process, and the EL thallus water content regulates that relationship. Although the GHG fluxes presented here were obtained under a controlled environment and are probably not representative of actual emissions in the field, more research is needed to fully comprehend ELs’ function in the C cycle. This particular research provides a solid foundation for future studies into the role of ELs in the C cycle of permafrost forest ecosystems under ongoing climate change (as non-methanogenesis processes in oxic environments). Full article

In addition to leaves, photosynthesis can occur in other green plant organs, including developing seeds of many crops. While the majority of studies examining photosynthesis are concentrated on the leaf level, the role of other green tissues in the production of total photoassimilates has been largely overlooked. The present work studies the photosynthetic behavior of leaves and non-foliar (pericarps, coats, and cotyledons) organs of pea (Pisum sativum L.) plants at the middle stage of seed maturation. The Chl a fluorescence transient was examined based on OJIP kinetics using the FluorPen FP 110. A discrepancy was observed between the performance index (PI_ABS) for foliar and non-foliar plant tissues, with the highest level noted in the leaves. The number of absorbed photons (ABS) and captured energy flow (TRo) per reaction center (RC) were elevated in the non-foliar tissues, which resulted in a faster reduction in Q_A. Conversely, the energy dissipation flux per RC (DIo/RC and PHI_Do) indicated an increase in the overall dissipation potential of active reaction centers of photosystem II. This phenomenon was attributed to the presence of a higher number of inactive RCs in tissues that had developed under low light intensity. Furthermore, the expression of genes associated with proteins and enzymes that regulate ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo) activity was observed, including chaperonins Cpn60α and Cpn60β, RuBisCO activase, as well as phosphoribulokinase. The expression of these genes was found to differ between foliar and non-foliar tissues, indicating that the activation state of RuBisCO may be modified in response to light intensity. Overall, the present study provides insights into the mechanisms by which non-foliar green tissues of plants adapt to efficient light capture and utilization under low light conditions. Full article

Rice production remains highly dependent on nitrogen (N). There is no positive linear correlation between N concentration and yield in rice cultivation because an excess of N can unbalance the distribution of photo-assimilates in the plant and consequently produce a lower yield. We intended to study these imbalances. Remote sensing is a useful tool for monitoring rice crops. The purpose of this study was to evaluate the effectiveness of using remote sensing to assess the impact of N applications on rice crop behavior. An experiment with three different doses (120, 170 and 220 kg N·ha⁻¹) was carried out over two years (2021 and 2022) in Valencia, Spain. Biomass, Leaf Area Index (LAI), plants per m², yield, N concentration and N uptake were determined. Moreover, reflectance values in the green, red, and NIR bands of the Sentinel-2 satellite were acquired. The two data matrices were merged in a correlation study and the resulting interpretation ended in a protocol for the evaluation of the N effect during the main phenological stages. The positive effect of N on the measured parameters was observed in both years; however, in the second year, the correlations with the yield were low, being attributed to a complex interaction with climatic conditions. Yield dependence on N was optimally evaluated and monitored with Sentinel-2 data. Two separate relationships between NIR–red and NDVI–NIR were identified, suggesting that using remote sensing data can help enhance rice crop management by adjusting nitrogen input based on plant nitrogen concentration and yield estimates. This method has the potential to decrease nitrogen use and environmental pollution, promoting more sustainable rice cultivation practices. Full article

Environmental stresses, including drought stress, seriously threaten food security. Previous studies reported that wheat F-box protein, TaFBA1, responds to abiotic stresses in tobacco. Here, we generated transgenic wheat with enhanced (overexpression, OE) or suppressed (RNA interference, RNAi) expression of TaFBA1. The TaFBA1-OE seedlings showed enhanced drought tolerance, as measured by survival rate and fresh weight under severe drought stress, whereas the RNAi plants showed the opposite phenotype. Furthermore, the OE plants had stronger antioxidant capacity compared to WT and RNAi plants and maintained stomatal opening, which resulted in higher water loss under drought stress. However, stronger water absorption capacity in OE roots contributed to higher relative water contents in leaves under drought stress. Moreover, the postponed stomatal closure in OE lines helped to maintain photosynthesis machinery to produce more photoassimilate and ultimately larger seed size. Transcriptomic analyses conducted on WT and OE plants showed that genes involved in antioxidant, fatty acid and lipid metabolism and cellulose synthesis were significantly induced by drought stress in the leaves of OE lines. Together, our studies determined that the F-box protein TaFBA1 modulated drought tolerance and affected yield in wheat and the TaFBA1 gene could provide a desirable target for further breeding of wheat. Full article

Soil salinity represents a significant factor affecting agricultural productivity and crop quality. The present study was conducted to investigate the effects of soil conditioner (SC) comprising halotolerant microorganisms on the soil fertility, yield, rice quality, and the physicochemical and structural properties of starch in hybrid rice under saline conditions. The experimental treatments were composed of two high-quality hybrid rice varieties, i.e., ‘Y Liangyou 957’ (YLY957) and Jing Liangyou 534 (JLY534), and two soil amendment treatments, i.e., the application of SC at control levels and 2250 kg hm⁻², or ‘CK and SC’, respectively. The crop was subjected to a mixture of fresh and sea water (EC 11 dS/m). The results demonstrated that the application of SC significantly enhanced the rice yield under salt stress conditions owing to an increase in the number of grains per panicle. Furthermore, SC was found to be effective in improving the organic matter and soil nutrient content. Furthermore, the application of SC resulted in an improvement in antioxidant defense, higher leaf SPAD values, and greater crop biomass, as well as the translocation of photo-assimilates at the heading stage. The application of SC not only improved the milling and appearance quality but also enhanced the taste value of rice by increasing the amylose and reducing the protein content. Furthermore, the application of SC also decreased the indentations on the surfaces of starch granules and cracks on the edges of the granules. The rice varieties subjected to SC exhibited excellent pasting properties, characterized by reduced proportions of amylopectin short chains and a lower gelatinization temperature and enthalpy of gelatinization. Overall, these findings serve to reinforce the efficacy of soil conditioner as a valuable tool to improve rice productivity and sustainability with improved rice grain quality under saline conditions. Full article

In a tropical savanna climate like Thailand, cassava can be planted all year round and harvested at 8 to 12 months after planting (MAP). However, it is not clear how water limitation during the dry season without rain affects carbon assimilation, partitioning, and yield. In this field investigation, six cassava genotypes were planted in the rainy season (August 2021) under continuous irrigation (control) or subjected to drought for 60 days from 3MAP to 5MAP during the dry season (November 2021 to January 2022) with no irrigation and rainfall. After that, the plants were rewatered and continued growing until harvest at 12MAP. After 60 days of stress, there were significant reductions in the mean net photosynthesis rate (Pn), petiole, and root dry weight (DW), and slight reductions in leaf, stem, and tuber DW. The mean starch concentrations were reduced by 42% and 16% in leaves and tubers, respectively, but increased by 12% in stems. At 6MAP after 30 days of rewatering, Pn fully recovered, and stem starch was remobilized resulting in a dramatic increase in the DW of all the organs. Although the mean tuber DW of the drought plants at 6MAP was significantly lower than that of the control, it was significantly higher at 12MAP. Moreover, the mean tuber starch concentration at 12MAP of the drought plants (18.81%) was also significantly higher than that of the controls (16.46%). In the drought treatment, the high-yielding varieties, RY9, RY72, KU50, and CMR38-125-77 were similarly productive in terms of tuber DW and starch concentration while the breeding line CM523-7 produced the lowest tuber biomass and significantly lower starch content. Therefore, for cassava planted in the rainy season in the tropical savanna climate, the exposure to drought during the early growth stage was more beneficial than the continuous irrigation. Full article

Leaf senescence is a complex trait which becomes crucial for grain filling because photoassimilates are translocated to the seeds. Therefore, a correct sync between leaf senescence and phenological stages is necessary to obtain increasing yields. In this study, we evaluated the performance of five deep machine-learning methods for the evaluation of the phenological stages of sunflowers using images taken with cell phones in the field. From the analysis, we found that the method based on the pre-trained network resnet50 outperformed the other methods, both in terms of accuracy and velocity. Finally, the model generated, Sunpheno, was used to evaluate the phenological stages of two contrasting lines, B481_6 and R453, during senescence. We observed clear differences in phenological stages, confirming the results obtained in previous studies. A database with 5000 images was generated and was classified by an expert. This is important to end the subjectivity involved in decision making regarding the progression of this trait in the field and could be correlated with performance and senescence parameters that are highly associated with yield increase. Full article

Zinc enrichment of edible food products, through the soil and/or foliar application of fertilizers, is a strategy that can increase the contents of some nutrients, namely Zn. In this context, a workflow for agronomic enrichment with zinc was carried out on irrigated Vitis vinifera cv. Syrah, aiming to evaluate the mobilization of photoassimilates to the winegrapes and the consequences of this for winemaking. During three productive cycles, foliar applications were performed with ZnSO₄ or ZnO, at concentrations ranging between 150 and 1350 g.ha⁻¹. The normal vegetation index as well as some photosynthetic parameters indicated that the threshold of Zn toxicity was not reached; it is even worth noting that with ZnSO₄, a significant increase in several cases was observed in net photosynthesis (P_n). At harvest, Zn biofortification reached a 1.2 to 2.3-fold increase with ZnSO₄ and ZnO, respectively (being significant relative to the control, in two consecutive years, with ZnO at a concentration of 1350 g.ha⁻¹). Total soluble sugars revealed higher values with grapes submitted to ZnSO₄ and ZnO foliar applications, which can be advantageous for winemaking. It was concluded that foliar spraying was efficient with ZnO and ZnSO₄, showing potential benefits for wine quality without evidencing negative impacts. Full article

For agricultural production, improving the rice harvest index (HI) through agricultural management practices is a major means to enhance water and N utilization efficiency and yield. Both irrigation regimes and nitrogen (N) rates are important aspects of agricultural management practices. However, it is unclear how the rice HI is affected by water and N. This study aimed to clarify the mechanism underlying the response of the rice HI to water and N, and to explore the most suitable water-saving and N reduction management practices to ensure yield. A two-year (2021~2022) field experiment was conducted on Mollisols in Northeast China. In this experiment, nine treatments were performed, involving three irrigation regimes (flooded irrigation, controlled irrigation, and “thin-shallow-wet-dry” irrigation) and three N rates (110, 99, and 88 kg/ha). The rice agronomic traits and transfer of photoassimilates under different water and N management practices were observed and studied; rice HI, WUE, and the NUE of rice was calculated and analyzed. The highest HI was achieved under controlled irrigation with a 99 kg/ha N rate, at values of 0.622 and 0.621 in 2021 and 2022, respectively. Controlled irrigation (CI) with an appropriate reduction in the N rate increased the proportion of productive tillers, the transfer rate of dry matter and non-structural carbohydrates (NSCs), the sugar–spikelet ratio, the grain–leaf ratio, and the leaf area index (LAI) during the heading–flowering stage. A subsequent analysis indicated that the main reason for the increase in the HI was the increase in the sugar–spikelet ratio during the heading–flowering stage. A high HI increased the rice yield by increasing the thousand-grain weight. The present study suggested that water-saving irrigation regimes and appropriate N reduction not only led to water and fertilizer resource savings but also improved agronomic characteristics during rice growth and enhanced transport capacity. Thus, these practices improved the rice HI and have enormous potential for increasing yield. Therefore, regulating the rice HI through water and N management methods should be considered an important strategy for improving rice yield. Full article

Blueberry (Vaccinium corymbosum L.) stands out among fruit in terms of three open physiological questions about its climacteric character, CO₂ uptake, and the absence or presence of stomata on its floral organs. The objective of the present study was to examine the structures of blueberry flowers and fruit to explain their contribution to CO₂ exchange and transpiration in order to clarify these discrepancies. Blueberries were dewaxed and the sepals/corolla removed for stomata counts, and their micromorphology was studied via LT-SEM. The fruit has stomata, contrary to beliefs in the literature, possibly because the stomata are occluded by the dense wax cover or ‘bloom’ and hidden on the distal part of the ovary in between and underneath the corolla. However, stomata were located on the distal part of the fruit surrounded by the sepals (calyx) and found predominantly on the abaxial sepals, while the adaxial side of the sepals and the proximal part of the ovary lacked stomata. The petals were devoid of stomata, trichomes, and chlorophyll and abscised after anthesis. In contrast, the sepals remained until maturity, contributing 5–7% to the berry surface but contributing to the majority of fruit stomata and chlorophyll. With 59–71% of the fruit’s chlorophyll, sepals were a significant source of the CO₂ uptake. Similarly, with 95% of the berry stomata, sepals were a significant source of water loss, measured via porometry of fruit with and without sepals. Overall, this study identified the ovary as a minor source and sepals as the dominant source of CO₂ and H₂O exchange in blueberries. Full article