Journal ArticleDOI
Abscisic acid and cytokinins in the root exudates and leaves and their relationship to senescence and remobilization of carbon reserves in rice subjected to water stress during grain filling.
TLDR
It is suggested that both ABA and cytokinins are involved in controlling plant senescence, and an enhanced carbon remobilization is attributed to an elevated ABA level in rice plants subjected to water stress.Abstract:
The possible regulation of senescence-initiated remobilization of carbon reserves in rice (Oryza sativa L.) by abscisic acid (ABA) and cytokinins was studied using two rice cultivars with high lodging resistance and slow remobilization. The plants were grown in pots and either well-watered (WW, soil water potential = 0 MPa) or water-stressed (WS, soil water potential = -0.05 MPa) from 9 days after anthesis until they reached maturity. Leaf water potentials of both cultivars markedly decreased at midday as a result of water stress but completely recovered by early morning. Chlorophyll (Chl) and photosynthetic rate (Pr) of the flag leaves declined faster in WS plants than in WW plants, indicating that the water deficit enhanced senescence. Water stress accelerated starch remobilization in the stems, promoted the re-allocation of pre-fixed (14)C from the stems to grains, shortened the grain-filling period and increased the grain-filling rate. Sucrose phosphate synthase (SPS, EC 2.4.1.14) activity was enhanced by water stress and positively correlated with sucrose accumulation in both the stem and leaves. Water stress substantially increased ABA but reduced zeatin (Z) + zeatin riboside (ZR) concentrations in the root exudates and leaves. ABA significantly and negatively, while Z+ZR positively, correlated with Pr and Chl of the flag leaves. ABA, not Z+ZR, was positively and significantly correlated with SPS activity and remobilization of pre-stored carbon. Spraying ABA reduced Chl in the flag leaves, and enhanced SPS activity and remobilization of carbon reserves. Spraying kinetin had the opposite effect. The results suggest that both ABA and cytokinins are involved in controlling plant senescence, and an enhanced carbon remobilization is attributed to an elevated ABA level in rice plants subjected to water stress.read more
Citations
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Journal ArticleDOI
The effect of drought and heat stress on reproductive processes in cereals.
TL;DR: The results achieved so far indicate that various plant organs, in a definite hierarchy and in interaction with each other, are involved in determining crop yield under stress.
Journal ArticleDOI
Source-to-sink transport of sugar and regulation by environmental factors
Rémi Lemoine,Sylvain La Camera,Rossitza Atanassova,Fabienne Dédaldéchamp,Thierry Allario,Nathalie Pourtau,Jean-Louis Bonnemain,Maryse Laloi,Pierre Coutos-Thévenot,Laurence Maurousset,Mireille Faucher,Christine Girousse,Pauline Lemonnier,Jonathan Parrilla,Mickaël Durand +14 more
TL;DR: Current knowledge about the phloem transport mechanisms is summarized and the effects of several abiotic (water and salt stress, mineral deficiency, CO2, light, temperature, air, and soil pollutants) and biotic andmutualistic and pathogenic microbes, viruses, aphids, and parasitic plants are reviewed.
Journal ArticleDOI
Abscisic Acid and Abiotic Stress Tolerance in Crop Plants
TL;DR: The role of ABA in response to abiotic stress at the molecular level and ABA signaling is discussed and the effect of A BA in respect to gene expression is dealt with.
Journal ArticleDOI
Grain filling of cereals under soil drying.
Jianchang Yang,Jianhua Zhang +1 more
TL;DR: If mild soil drying is properly controlled during the later grain-filling period in rice (Oryza sativa) and wheat (Triticum aestivum), it can enhance whole-plant senescence, lead to faster and better remobilization of carbon from vegetative tissues to grains, and accelerate the grain- filling rate.
Journal ArticleDOI
Hormonal changes during salinity-induced leaf senescence in tomato (Solanum lycopersicum L.)
Michel Edmond Ghanem,Alfonso Albacete,Cristina Martínez-Andújar,Manuel Acosta,M. Remedios Romero-Aranda,Ian C. Dodd,Stanley Lutts,Francisco Pérez-Alfocea +7 more
TL;DR: In this paper, the influence of different hormonal changes on salt-induced leaf senescence is discussed, including changes in abscisic acid (ABA), cytokinins, the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), and the auxin indole-3-acetic acid (IAA).
References
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Journal ArticleDOI
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TL;DR: This chapter discusses the role of hormones in plant growth, development, and senescence, and the mechanism of action of auxin and cytokinin in prokaryotes, as well as other aspects of hormone synthesis and action.
Root signals and the regulation of growth and development of plants in drying soil
TL;DR: The role of the root signal in the regulation of plant development is discussed in this article, where a root signal is used to regulate the development of a plant and to measure water availability.
Journal ArticleDOI
The molecular biology of leaf senescence
TL;DR: Experiments with transgenic plants and mutants are already shedding light on the role played by cytokinins and ethylene in regulating senescence in leaves, and analysis of the regulatory mechanisms controlling the expression ofSenescence-induced genes will allow the signalling pathways that are involved in the regulation of senescences to be elucidated.