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Relationships between Leaf Water Potential, Canopy Temperature and Transpiration in Irrigated and Nonirrigated Wheat
Author(s) -
Kumar Alok,
Tripathi R. P.
Publication year - 1991
Publication title -
journal of agronomy and crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.095
H-Index - 74
eISSN - 1439-037X
pISSN - 0931-2250
DOI - 10.1111/j.1439-037x.1991.tb00879.x
Subject(s) - transpiration , agronomy , loam , canopy , vapour pressure deficit , environmental science , sowing , irrigation , water stress , water potential , soil water , horticulture , biology , botany , photosynthesis , soil science
Research is needed to characterize the crop response to soil water deficit through plant parameters. Leaf water potential (LWP), canopy temperature (CT) and transpiration rate (TR) served as indicators of stress and were measured using a pressure chamber, infrared thermometer and porometer, respectively, in irrigated and nonirrigated wheat ( Triticum aestivum L.) grown on Haldi loam soil. Nonirrigated wheat had consistently higher CT and, lower LWP and TR during the day. As drought intensified, differences between irrigated and nonirrigated wheat became large and the maximum differences in CT, LWP and TR occurred at 14.00 h where they equalled 3.8 °C, 9 bar and 7.6 μg cm −2: sec −1 , respectively, on 109 days after sowing (DAS). In nonirrigated wheat LWP declined at a faster rate until the peak stress period (14.00 h) approached and recovered slowly in the later afternoon and TR increased slowly in the forenoon and declined rapidly in the afternoon as compared with irrigated wheat. Canopy temperature (CT) of nonirrigated plants increased earlier during forenoon and remained higher later in the afternoon than CT of irrigated plants. At a same TR, lower values of LWP and higher values of CT were observed in the afternoon than in the forenoon due to which the phenomenon of hysteresis exhibited. The degree of hysteresis increased with increasing plant water deficit and crop age.