Functional Plant Biology最新文献

Light intensity is a critical environmental factor influencing plant growth and development. To survive high light conditions, plants have evolved various protective mechanisms, including non-photochemical quenching (NPQ). However, NPQ can limit effective photosynthetic yield when transitioning to low light conditions. This phenomenon is underexplored in cassava (Manihot esculenta ), a starchy storage root crop known for its high biological efficiency and climate resilience. To address this knowledge gap, we assessed the photoprotective abilities and growth responses of six cassava varieties under natural environmental light conditions (control) and intermittent high light (IHL) conditions by adding 900μmolm-2 s-1 using full-spectrum LED lights, on top of the natural ambient daylight. Our results demonstrated a significant impact of light treatment on aboveground biomass, total crop biomass, chlorophyll a and b content, photosynthetic rate, and NPQ values during transitions from low to high light and vice versa. Notably, cassava variety 'Sree Suvarna' exhibited the highest yield under both control and IHL conditions. These findings suggest that screening cassava varieties for their ability to postpone photoinhibition and recover quickly from photoinhibition may enhance photosynthetic performance. Such strategies have important implications for improving the efficiency and resilience of cassava crops, ultimately contributing to sustainable agricultural productivity.

Freeze-thaw is a common stress at high altitudes in northern China. There is a risk of cadmium (Cd) contamination in the region. γ-aminobutyric acid (GABA) is a natural product that regulates plant growth. Rye (Secale cereale ) was used as research material to investigate the physiological effects of exogenous GABA on rye seedlings under the single and combined stresses of freeze-thaw and cadmium. The results showed that the combined stress severely inhibited shoot length, root length, fresh weight, and dry weight, increased malondialdehyde and hydrogen peroxide contents, and significantly decreased superoxide dismutase (SOD) activity. Foliar application of 5mM GABA alleviated the negative effects of stress on seedling growth, increased soluble protein content, and reduced malondialdehyde and hydrogen peroxide contents. Exogenous GABA application also enhanced the activities of SOD and peroxidase (POD). Additionally, the presence of exogenous GABA activated the GABA metabolic process and encouraged the accumulation of phytochelatins, glutathione, and non-protein thiol. These results indicate that exogenous GABA can effectively improve the resistance of rye seedlings to freeze-thaw and Cd by regulating the antioxidant enzyme system and enhancing its own detoxification mechanism, and they provide a basis for future applications of exogenous GABA, which is beneficial for ecological protection.

Xero-halophytes are the salt-tolerant plants of dry habitats that adapt efficient strategies to endure extreme salt and water fluctuations. This study elucidated the adaptations related to PSII photochemistry, photoprotection, and photoinhibition in six C4 xero-halophytes (Atriplex stocksii , Haloxylon stocksii , Salsola imbricata, Suaeda fruticosa, Desmostachya bipinnata , and Saccharum griffithii ) grown in their native habitats. Chlorophyll a fluorescence quenching measurements suggested that S. imbricata and H. stocksii maintained efficient PSII photochemistry by downregulating heat dissipation and keeping a high fraction of open PSII centres that indicates plastoquinone (PQ) pool oxidation. Fluorescence induction kinetics revealed that S. imbricata demonstrated the highest performance index of PSII excitation to the reduction of end electron acceptors. S. fruticosa sustained photochemical efficiency through enhanced dissipation of excess energy and a low fraction of open PSII centres, indicating PQ reduced state. The large light-harvesting antenna size, deduced from the chlorophyll a /b ratio in S. fruticosa apparently led to the superior performance index of PSII excitation to the reduction of intersystem electron carriers. A. stocksii retained more open PSII centres with responsive non-photochemical quenching to safely dissipate excess energy. Despite maintaining the highest pigment contents and stoichiometry, A. stocksii remained lowest in both performance indices. The grass species D. bipinnata and S. griffithii kept fewer PSII centres open during photoinhibition, as evidenced by downregulation of PSII operating efficiency. The results provide insights into the differential modulation of PSII photochemical efficiency through dynamic control of photoprotective energy dissipation, PQ pool redox states, and photoinhibitory shutdown in these xero-halophytes.

Climate change-driven drought events are becoming unescapable in an increasing number of areas worldwide. Understanding how plants are able to adapt to these changing environmental conditions is a non-trivial challenge. Physiologically, improving a plant's intrinsic water use efficiency (WUEi ) will be essential for plant survival in dry conditions. Physically, plant adaptation and acclimatisation are constrained by a plant's anatomy. In other words, there is a strong link between anatomical structure and physiological function. Former research predominantly focused on using 2D anatomical measurements to approximate 3D structures based on the assumption of ideal shapes, such as spherical spongy mesophyll cells. As a result of increasing progress in 3D imaging technology, the validity of these assumptions is being assessed, and recent research has indicated that these approximations can contain significant errors. We suggest to invert the workflow and use the less common 3D assessments to provide corrections and functions for the more widely available 2D assessments. By combining these 3D and corrected 2D anatomical assessments with physiological measurements of WUEi , our understanding of how a plant's physical adaptation affects its function will increase and greatly improve our ability to assess plant survival.

Bassinosteroids (BRs) can induce plant defence responses and promote plant growth. In this work, we evaluated the effect of a natural (EP24) and a synthetic (BB16) brassinosteroid on strawberry (Fragaria vesca ) plants exposed to saline stress. Treated plants showed higher shoot dry weight and root growth compared to untreated control plants. In BR-treated plants, crown diameters increased 66% and 40%, leaf area 148% and 112%, relative water content in leaves 84% and 61%, and SPAD values 24% and 26%, in response to BB16 and EP24, respectively. A marked stomatal closure, increased leaflet lignification, and a decrease in cortex thickness, root diameter and stele radius were also observed in treated plants. Treatments also reduces stress-induced damage, as plants showed a 34% decrease in malondialdehyde content and a lower proline content compared to control plants. A 22% and 15% increase in ascorbate peroxidase and total phenolic compound activities was observed in response to BB16, and a 24% increase in total flavonoid compound in response to both BRs, under stress conditions. These results allow us to propose the use of BRs as an environmentally safe crop management strategy to overcome salinity situations that severely affect crop yield.

Structural and physiological leaf traits and their plasticity were compared in the hemiepiphyte Vanilla phaeantha . This species grows along a phorophyte reaching different understorey positions and exhibiting diverse responses to environment changes. We analysed three height strata above the ground, establishing a light gradient, and considering seasonal water fluctuations. The upper leaves had higher area and mass and were less pigmented. The dry season induced a reduction of approximately 2h of stomatal opening over the diel 24h crassulacean acid metabolism (CAM) cycle in the leaves at all understorey positions. The leaves more exposed to sunlight were larger with higher titratable acidity during the rainy season, while the leaves near the ground maintained the same rates of stomatal conductance and nocturnal acidification between seasons, with lowest values of carbon isotopes in the rainy season. Our research showed that some structural leaf traits (such as specific leaf mass, biomass, and saturated water content) are sensitive to variation in understorey position. In contrast, other physiological traits (stomatal conductance, transpiration, and fluorescence parameters) are more sensitive to seasonal variations. The results are a novelty in assessing the variation of CAM along the same plant in a height gradient and under field conditions.

Glycoside hydrolases (GHs) are important in metabolic processes involving diverse carbohydrate-based substances found inside plant tissues. Potatoes (Solanum tuberosum) are rich in starchy carbohydrates, suggesting the role of GHs in their metabolic pathways. In this study, we examine the GH superfamily in potato where 366 potential GHs were identified using a similarity search method. Genes were subjected to further characterisation to gain insights into their structural composition, functional properties and distribution patterns across tissue types. Several in silico methodologies were also employed to investigate the physicochemical features, conserved motifs, chromosomal mapping, duplication events, syntenic links with tomato (Solanum lycopersicum), subcellular localisations, secondary structures and phylogenetic relationships. Cis-elements in StGHs revealed that the promoters of StGHs contain cis-elements that are responsive to phytohormones that are involved in plant growth and development, and are associated with stress responses. RNA-seq data identified significant changes in expression levels of GH16, GH17, GH18, GH19 and GH28 members under stress conditions. Expression patterns of several GHs were confirmed using real time quantitative PCR in response to stress. StGH16.24 expression increased after 3 days of drought stress, whereas StGH16.30 continuously increased under salt stress. Potential interactions between potato miRNAs and StGH revealed 393 and 627 interactions under drought and salt stress, respectively. Our findings offer insights into specific functions of GHs in diverse developmental stages and stress-related challenges in potato and other plants.

The water relation strategy is a key issue in climate change. Given the difficulty of determining water relations strategy, there is a need for simple traits with a solid theoretical basis to estimate it. Traits associated with resource allocation patterns along a 'fast-slow' plant economics spectrum are particularly compelling, reflecting trade-offs between growth rate and carbon allocation. Avocado (Persea americana ), fig tree (Ficus carica ), mandarin (Citrus reticulata ), olive (Olea europaea ), pomegranate (Punica granatum ), and grapevine (Vitis vinifera ) were characterised in terms of iso-anisohydric strategy through stomatal behaviour, water potential at the turgor loss point (TLP), and hydroscape area. Additionally, the association of these metrics with leaf mass per area (LMA) and wood density (WDen) was explored. We observed high coordination between LMA and WDen, and both traits were related to metrics of water relation strategy. More anisohydric species tended to invest more carbon per unit leaf area or unit stem volume, which has implications for hydraulic efficiency and water stress tolerance. WDen and TLP were the most powerful traits in estimating the water relation strategy for six fruit species. These traits are easy to measure, time-cost efficient, and appear central to coordinating multiple traits and behaviours along the water relations strategies.

In wheat (Triticum aestivum ), canopy architecture, culm diameter and stem strength are the key providers of lodging tolerance. To better understand the lodging phenomenon and determine the best linked trait to lodging, a study of lodging resistance was conducted in both artificially-induced and natural lodging conditions. Various morphological, phenological and biochemical traits, such as acid detergent fibre, acid detergent lignin, cellulose and activity of lignin-synthesising enzymes (phenylalanine ammonia lyase and tyrosine ammonia lyase) were recorded. Anatomical features were also examined by light microscopy, using the Wiesner reaction. Genotype C306 demonstrated the highest susceptibility to lodging compared to other varieties due to its limited production of lignin-synthesising enzymes, as well as its taller plant height and narrower culms. The dwarf mutants (DM6 and DM7) have a stronger resistance against lodging because they have thick stems and a short plant canopy structure. The most suitable donors for lodging are semidwarf varieties (HD2967, DPW621-50, DBW88) because they have higher production of lignin and lignin-synthesising enzymes. Grey correlation analysis also confirmed the ability of these three genotypes to tolerate lodging. The genotypes studied were comprehensively ranked. The study also includes an effort towards the standardisation of lodging methodology under artificial conditions.

Breeding abiotic stress-tolerant varieties of Rosa chinensis is a paramount goal in horticulture. WRKY transcription factors, pivotal in plant responses to diverse stressors, offer potential targets for enhancing stress resilience in R. chinensis . Using bioinformatics and genomic data, we identified RcWRKY transcription factor genes, characterised their chromosomal distribution, phylogenetic relationships, structural attributes, collinearity, and expression patterns in response to saline stress. Leveraging bidirectional database searches, we pinpointed 66 RcWRKY genes, categorised into three groups. All except RcWRKY60 encoded DNA Binding Domain and Zinc Finger Motif regions of the WRKY domain. Expansion of the RcWRKY gene family was propelled by 19 segmental, and 2 tandem, duplications. We unveiled 41 and 15 RcWRKY genes corresponding to 50 AtWRKY and 17 OsWRKY orthologs respectively, indicating postdivergence expansion. Expression analyses under alkaline stress pinpointed significant alterations in 54 RcWRKY genes. Integration of functional roles from their Arabidopsis orthologs and cis -acting elements within their promoters, along with quantitative reverse transcription PCR validation, underscored the importance of RcWRKY27 and 29 in R. chinensis ' alkaline stress response. These findings offer insights into the biological roles of RcWRKY transcription factors, as well as the regulatory dynamics governing R. chinensis ' growth, development, and stress resilience.