Diffusive conductance of rice (Oryza sativa) leaves during gradually induced soil water stress |
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Authors: | B C SAINI T R RATHORE |
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Institution: | Department of Soil Science, G. B. Pant University of Agriculture and Technology, Pantnagar-263145, District Nainital, India |
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Abstract: | The diffusive conductance (Cs) of rice (Oryza sativa cvs Jaya and Bala) leaves was measured during a soil drying cycle from flooding to decreasing soil water potential (φs) in a controlled-environment chamber. Plants were grown continuously under 5 cm submergence up to 69 days after transplanting and thereafter were subjected to gradual soil drying for a period of 17 days in the vegetative growth stage. In both the cultivars, the values of Cs were generally more on adaxial than abaxial leaf surfaces. This response of stomata during the period of soil drying was independent of leaf rolling. Further, the slopes of the curves (Cs, vs φs) also did not differ significantly (P= 0·05). The total Cs, of both cultivars during flooding was almost equal (0·60 cm s-1) but at the end of the soil drying cycle, the values of total Cs, were 0·11 cm s-l at ψs of -1·3 MPa and 0·08 cm s-1 at ψs, of -0·8 MPa in cvs Jaya and Bala, respectively. For total Cs, slopes differed significantly (P = 0·05). A close relationship between total Cs, and ψs, in both cultivars (Cs, = 0·58-0·40 ψs, for cv. Jaya and Cs= 0·46-0·56 ψs, for cv. Bala) indicated that stomata were sensitive to increasing soil water deficit. |
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