The response of groundnut (Arachis hypogaea L.) to timing of irrigation. II. 14C-partitioning and plant water status

Stirling, C M and Black, C R and Ong, C K (1989) The response of groundnut (Arachis hypogaea L.) to timing of irrigation. II. 14C-partitioning and plant water status. Journal of Experimental Botany, 40 (221). pp. 1363-1373. ISSN 0022-0957

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Abstract

Finite quantities of water were applied at different growth stages of groundnuts grown in a controlled environment. Soil moisture deficits were imposed between sowing and pod initiation or between pod initiation and final harvest by withholding or applying water and 14CO2 was supplied on 5-6 occasions between 50 and 97 d after sowing. Leaves were the primary sites of 14CO2 fixation, though their contribution generally declined late in the season; whereas fixation by stems was initially low but increased sharply when stress was released in the late-irrigated stands. 14C-fixation by stem apices and pegs also rose sharply following irrigation of the late-stressed stands. Leaves were the primary source of assimilates, but translocation tended to decrease as the season progressed, even in the late-irrigated stands. Stems were initially the major sinks, but their sink activity disappeared almost completely when stress was released in the late-irrigated stands. Assimilate import by stem apices declined progressively and pod sink activity was negligible in the late-stressed stand, but both increased markedly when early-season stress was released. Leaf water status showed marked diurnal variation; pegs showed less variation and maintained much higher turgor levels, largely because of their lower solute potentials. Marked osmotic adjustment occurred in expanding but not in mature leaves, allowing them to maintain higher turgor levels during periods of severe stress. This adjustment was rapidly lost when stress was released. The observed changes in assimilate production and partitioning preceded detectable changes in bulk turgor levels

Item Type:	Article
Divisions:	UNSPECIFIED
CRP:	UNSPECIFIED
Uncontrolled Keywords:	Groundnut, irrigation, partitioning, water status
Subjects:	Mandate crops > Groundnut
Depositing User:	Ms K Syamalamba
Date Deposited:	25 Nov 2011 05:13
Last Modified:	25 Nov 2011 05:13
URI:	http://oar.icrisat.org/id/eprint/4330
Official URL:	http://dx.doi.org/10.1093/jxb/40.12.1363
Projects:	UNSPECIFIED
Funders:	University of Nottingham (C.M.S) and the UK Overseas Development Administration (C.K.O.)
Acknowledgement:	We thank the University of Nottingham (C.M.S) and the UK Overseas Development Administration (C.K.O.) for financial support, ICRISAT for providing seeds and our colleagues for environmental control
Links:	Author

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