Journal ArticleDOI
Abscisic Acid and Cytokinins as Possible Root-to-Shoot Signals in Xylem Sap of Rice Plants in Drying Soil
TLDR
Xylem sap contained considerable amounts of bound ABA, the level of which increased during total root drying and decreased again after rewatering, and level of cytokinins, zeatin (t-Z)+zeatin riboside ( t-ZR) and isopentenyladenine (2iP) + isopENTenyladenosine ( 2iPA), on the contrary, decreased duringRoot drying and increased again afterRewatering.Abstract:
Seedlings of rice cv. IR 36 were grown in soil in small pots with a horizontally divided root system: after 6-7 weeks, about 20% of the entire root system had protruded through the holes at the base of the pots and was kept in contact with nutrient solution. At this stage the plants were exposed to three different treatments: (a) the soil was kept watered and the protruding free roots were dried in air; (b) the free roots were kept moist and the soil left unwatered; (c) both soil and protruding roots were left unwatered for 30 h and then rewatered. During the first hours of treatment a and b, a decline in stomatal conductance was observed, whereas the stem water potential remained unchanged. The concentration of abscisic acid (ABA) in the xylem, however, increased. At later stages of treatment a and b, the stem water potential began to decrease with a parallel further increase of xylem ABA. Xylem sap contained considerable amounts of bound ABA, the level of which increased during total root drying and decreased again after rewatering. Level of cytokinins, zeatin (t-Z)+zeatin riboside (t-ZR) and isopentenyladenine (2iP) + isopentenyladenosine (2iPA), on the contrary, decreased during root drying and increased again after rewatering. The results are discussed with regard to a possible function of ABA and cytokinins as root-to-shoot signals.read more
Citations
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Journal ArticleDOI
Grapevine under deficit irrigation: hints from physiological and molecular data.
Maria Manuela Chaves,Maria Manuela Chaves,Olfa Zarrouk,Rita Francisco,J. M. Costa,J. M. Costa,Thiago de Santana Santos,Thiago de Santana Santos,A. P. Regalado,M. L. Rodrigues,Carlos M. Lopes +10 more
TL;DR: Rules under water deficit of genes and proteins of the various metabolic pathways responsible for berry composition and therefore wine quality are reviewed, and differences in this respect between grapevines varieties and experimental conditions are discussed.
Book ChapterDOI
Further Progress in Crop Water Relations
TL;DR: The potential for increased irrigation is limited, so that future population increases will need to be fed from higher food production per unit land area and without the aid of increased irrigation resources.
Journal ArticleDOI
The exodermis: a variable apoplastic barrier
TL;DR: It is concluded that, by regulating the extent of apoplastic barriers and their chemical composition, plants can effectively regulate the uptake or loss of water and solutes.
Journal ArticleDOI
Long-distance ABA Signaling and Its Relation to Other Signaling Pathways in the Detection of Soil Drying and the Mediation of the Plant’s Response to Drought
TL;DR: Evidence is reviewed for a variety of long-distance signaling pathways involving hormones and nutrient ions moving in the xylem sap that allow regulation of plant growth, development and functioning, and particularly shoot water status, as distinct from stress lesions in growth and other processes as a reaction to perturbations such as soil drying.
Journal ArticleDOI
Stomatal control in tomato with ABA‐deficient roots: response of grafted plants to soil drying
TL;DR: It is demonstrated that stomatal closure in response to soil drying can occur in the absence of leaf water deficit, and does not require ABA production by roots.
References
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Journal ArticleDOI
Root Signals and the Regulation of Growth and Development of Plants in Drying Soil
William J. Davies,Jianhua Zhang +1 more
Journal ArticleDOI
A monoclonal antibody to (S)-abscisic acid: its characterisation and use in a radioimmunoassay for measuring abscisic acid in crude extracts of cereal and lupin leaves.
Steve Quarrie,P. N. Whitford,Nigel E. J. Appleford,Trevor L. Wang,S. K. Cook,I. E. Henson,B. R. Loveys +6 more
TL;DR: The development of a radioimmunoassay for ABA using the antibody, which had a high selectivity for the free acid of (S)-cis, trans-ABA, and could be assayed reliably in the RIA over a range of 100 to 4000 pg ABA per assay vial, is described.
Journal ArticleDOI
Changes in the concentration of ABA in xylem sap as a function of changing soil water status can account for changes in leaf conductance and growth
Jianhua Zhang,William J. Davies +1 more
TL;DR: The manipulations suggested that the increases in ABA concentration in xylem sap, which resulted from soil drying, were adequate to explain the observed variation in stomatal conductance and might also explain the restriction in leaf growth rate.
Journal ArticleDOI
Kinetin‐like Activity in Root Exudate of Water‐stressed Sunflower Plants
Chanan Itai,Yoash Vaadia +1 more
Journal ArticleDOI
Long Distance Transport of Abscisic Acid in NaCI-Treated Intact Plants of Lupinus albus
TL;DR: The data suggest that ABA may serve as a hormonal stress signal from the root system and change of carbon, nitrogen and abscisic acid contents of individual organs were determined after germination.
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