On a global basis, water is a paramount factor in determining the distribution of species, and the responses and adaptations of a species to water stress are critical for its success in any environmental niche. Numerous studies have reported a myriad of changes elicited by water stress. The changes observed are dependent on the species under study and on the severity, duration, and time course of the stress. Before reviewing the changes in detail, we will first present an overview of stress and responses using the stress-strain concept of physics. Next, we will discuss specific water-related parameters for quantifying plant water status and briefly consider how changes in the parameters may affect plant functions. This is followed by the main body which first reviews and analyzes selected responses to water stress and then examines the integrated adaptive behavior of whole plants.

Physiological Responses to Moderate Water Stress

Preface Principles of Photosynthesis Mechanisms of Photosynthetic Oxygen Evolution and the Fundamental Hypotheses of Photosynthesis (Yuzeir Zeinalov) Thermoluminescence as a Tool in the study of Photosynthesis (Anil S. Bhagwat and Swapan K. Bhattachrjee) Biochemistry of Photosynthesis Chlorophyll Biosynthesis - A review (Benoit Schoefs and Martine Bertrand) Chloroplast Biogenesis 90, Probing the Relationship between Chlorophyll Biosynthetic Routes and the Topography of Chloroplast Biogenesis by Resonance Excitation Energy Transfer Determinations (Constantin A. Rebeiz, Karen J. Kopetz, and Vladimir L. Kolossov, USA) Protochlorophyllide Photoreduction - A review (Martine Bertrand and Benoit Schoefs) Formation and Demolition of Chloroplast during Leaf Ontogeny (Basanti Biswal) Role of Phosphorus in Photosynthetic Carbon Metabolism (Anna M. Rychter and I.M. Rao) Inhibition on Inactivation of Higher Plant Chloroplast Electron Transport (Rita Barr and Frederick L. Crane) Molecular Aspects of Photosynthesis: Photosystems, Photosynthetic Enzymes and Genes Photosystem I Structures and Functions (Teisuo Hiyama) Covalent Modification of Photosystem II Reaction-Center Polypeptides (Julian P. Whitelegge) Reactive Oxygen Species as Signaling Molecules Controlling Stress Adaptation in Plants (Tsanko Gechev, Ilya Gadjev, Stefan Dukiandjiev, and Ivan Minkov) Plastid Morphogenesis (Jan Hudak, Eliska Galova, and Lenka Zemanova) Plastid Proteases (Dennis E. Buetow) Supramolecular Organization of Water-Soluble Photosynthetic Enzymes Along the Thylakoid Membranes in Chloroplasts (Jayashree K. Sainis and Michael Melzer) Cytochrome C6 Genes in Cyanobacteria and Higher Plants (Kwok Ki Ho) Atmospheric and Environmental Factors Affecting Photosynthesis External and Internal Factors Responsible for Midday Depression of Photosynthesis (Da-Quan Xu and Yun-Kang Shen) Root Oxygen Depravation and the Reduction of Leaf Stomatal Aperture and Gas Exchange Effects on Photosynthesis (R.E. Sojka, H.D. Scott, and D.M. Oosterhuis) Rising Atmospheric CO2 and C4 Photosynthesis (Joseph C.V. Vu) Influence of High Light Intensity on Photosynthesis: Photoinhibition and Energy Dissipation (Robert Carpentier) Development of Functional Thylakoid Membranes: Regulation by Light and Hormones (Peter Nyitrai) Photosynthetic Pathways in Various Crop Plants Photosynthetic Carbon Assimilation of C3, C4 and CAM Pathways (Anil S. Bhagwat) Photosynthesis in Non-Typical C4 Species (Maria Valeria Lara and Carlos Santiago Andreo) Photosynthesis in Lower and Monocellular Plants Regulation of Phycobilisome Biosynthesis and Degradation in Cyanobacteria (Johannes Geiselmann, Jean Houmard, and Benoit Schoefs) Photosynthesis in Higher Plants Short-Term and Long-Term Regulation of Photosynthesis During Leaf Development (Dan Stessman, Martin Spalding, and Steven Rodermel) Recent Advances in Chloroplast Development in Higher Plants (Ilia D. Denev, Galina T. Yahubian, and Ivan N. Minkov) Photosynthesis in Different Plant Parts Photosynthesis in Leaf, Stem, Flower, and Fruit (Abdul Wahid, and Ejaz Rasul) Photosynthesis and Plant/Crop Productivity and Photosynthetic Products Photosynthetic Plant Productivity (Lubomir Natr and David W. Lawlor) Photosynthates Formation and Partitioning in Crop Plants (Alberto A. Iglesias and F.E. Podesta) Photosynthesis and Plant Genetics Crop Radiation Use Efficiency - Avenue for Genetic Improvement (G.V. Subbarao, O. Ito, and W.L. Berry) Physiological Perspectives on Improving Crop Adaptation to Drought - Justification for a Systemic Compnent-Based Approach (G.V. Subbarao, O. Ito, R. Serraj, J.H. Crouch, S. Tobita, K. Okada, C.T. Hash, R. Ortiz, and W.L. Berry) Photosynthetic Activity Measurements and Analysis of Photosynthetic Pigments Whole-Plant CO2 Exchange as a Non-Invasive Tool for Measuring Growth (Evangelos D. Leonardos, and Bernard Grodzinski) Approaches to Measuring Plant Photosynthetic Activity (Elena Masarovicova and Katarina Kralova) Analysis of Photosynthetic Pigments: An Update (Martine Bertrand, Jose L. Garrido, and Benoit Schoefs) Photosynthesis and Its Relationship with other Plant Physiological Processes Photosynthesis, Respiration, and the Limits to Growth (Bruce N. Smith, Heidi A. Summers, Emily A. Keller, and Tonya Thygerson) Nitrogen Assimilation and Carbon Metabolism (Alberto A. Iglesias, Maria J. Estrella, and Fernando Pieckenstain) Leaf Senescence (Agnieszka Mostowska) Photosynthesis Under Environmental Stress Conditions Photosynthesis in Plants under Stressful Conditions (Rama Shanker Dubey) Photosynthetic Response of Green Plants to Environmental Stress: Inhibition of Photosynthesis and Adaptational Mechanisms (Basanti Biswal) Salt and Drought Stress Effects on Photosynthesis, Enzyme Cohesion and High Turn Over Metabolite Shuttling, Essential for Functioning of Pathways, Is Impaired by Changes in Cytosolic Water Potential (B, Huchzermeyer and H.W. Koyro) Photosynthetic Carbon Metabolism of Crops under Salt Stress (Bruria Heuer) Photosynthesis under Drought Stress (Habib-ur-Rahman Athar and Muhammad Ashraf) Role of Plant Growth Regulators in Stomatal Limitation to Photosynthesis During Water Stress (Jana Pospisilova and Ian C. Dodd) Adverse Effects of UV-B Light on the Structure and Function of the Photosynthetic Apparatus (Imre Vass, Andras Szilard, and Cosmin Sicora) Heavy Metal Toxicity Induced Alterations in Photosynthetic Metabolism in Plants (Shruti Mishra and R.S, Dubey) Effects of Heavy Metals on Chlorophyll-Protein Complexes in Higher Plants: Causes and Consequences (Eva Sarvari) Photosynthesis in the Past, Present, and Future The Origin and Evolution of C4 Photosynthesis (Bruce N. Smith)

Handbook of Photosynthesis

Extensive studies have been undertaken on senescence processes in barley and wheat and their importance for the nitrogen use efficiency of these crop plants. During the senescence processes, proteins are degraded and nutrients are re-mobilised from senescing leaves to other organs, especially the developing grain. Most of the proteins degraded reside in the chloroplasts, with Rubisco constituting the most dominant protein fraction. Despite intensive studies, the proteases responsible for Rubisco degradation have not yet been identified. Evidence for degradation of stromal proteins outside of chloroplasts is summarised. Rubisco is thought to be released from chloroplasts into vesicles containing stroma material (RCB = Rubisco-containing bodies). These vesicles may then take different routes for their degradation. Transcriptome analyses on barley and wheat senescence have identified genes involved in degradative, metabolic and regulatory processes that could be used in future strategies aimed at modifying the senescence process. The breeding of crops for characters related to senescence processes, e.g. higher yields and better nutrient use efficiency, is complex. Such breeding has to cope with the dilemma that delayed senescence, which could lead to higher yields, is correlated with a decrease in nutrient use efficiency. Pinpointing regulatory genes involved in senescence might lead to tools that could effectively overcome this dilemma.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1438-8677.2008.00114.x

Leaf senescence and nutrient remobilisation in barley and wheat.

Water and nitrogen limitations in soybean grain production I. Model development

Oilseed rape (Brassica napus L.) is commonly grown for oil or bio-fuel production, while the seed residues can be used for animal feed. It can also be grown as a catch crop because of its efficiency in extracting mineral N from the soil profile. However, the N harvest index is usually low, due in part to a low ability to remobilize N from leaves and to the fall of N-rich leaves which allows a significant amount of N to return to the environment. In order to understand how N filling of pods occurs, experiments were undertaken to quantify N flows within the plant by (15)N labelling and to follow the changes in soluble protein profiles of tissues presumed to store and subsequently to remobilize N. Whereas N uptake increased as a function of growth, N uptake capacity decreased at flowering to a non-significant level during pod filling. However, large amounts of endogenous N were transferred from the leaves to the stems and to taproots which acted as a buffering storage compartment later used to supply the reproductive tissue. About 15% of the total N cycling through the plant were lost through leaf fall and 48%, nearly all of which had been remobilized from vegetative tissues, were finally recovered in the mature pods. SDS-PAGE analysis revealed that large amounts of a 23 kDa polypeptide accumulated in the taproots during flowering and was later fully hydrolysed. Its putative function of storage protein is further supported by the fact that when plants were grown at lower temperature, both flowering, its accumulation and further mobilization were delayed. The overall results are discussed in relation to plant strategies which optimize N cycling to reproductive sinks by means of buffering vegetative tissues such as stems and taproots.

/pdf/nitrogen-storage-and-remobilization-in-brassica-napus-l-2rilk09epg.pdf

Nitrogen storage and remobilization in Brassica napus L. during the growth cycle: nitrogen fluxes within the plant and changes in soluble protein patterns

R. T. Giaquinta

Papers

Changes in Photosynthesis, Ribulose Bisphosphate Carboxylase, Proteolytic Activity, and Ultrastructure of Soybean Leaves during Senescence1