Leaf properties related to the photosynthetic response to drought in upland and lowland rice varieties
1986
Tsunoda, S. | Fukoshima, M.T.
Four upland and two lowland varieties were grown on flooded and dry soil in pots in a glasshouse. Photosynthetic rate (P), transpiration rate (T), and water content (W) of the second expanded leaf from the top of the main stem were measured under controlled aeration and illumination in a leaf chamber in the laboratory, together with leaf area (La), dry matter content (DM), nitrogen content (N), stomatal frequency (Sf), and total vessel cross-sectional area at the base of the leaf blade (Va). P/La was positively related to T/La and Sf/La among six varieties when they were grown on flooded soil. IR 8, a semidwarf indica lowland variety, showed the highest P/La with the highest Sf/La and T/La. When grown on dry soil P/La was positively correlated with W/DM, the latter being negatively related to T/Va. Two upland varieties, African Moroberekan and Brazilian lAC 1246, showed the highest P/La on dry soil, keeping a higher W/DM with a lower T/La and a lower T/Va. Daytime leaf diffusive conductance (1/rL and leaf water potential (ψ/L) measured on the same or the same stage leaf in the glasshouse were positively correlated with the W/ DM measured in the laboratory among varieties grown on dry soil. Simultaneous observation of P, T and Win the laboratory indicated nonstomatal reduction in P/La due to leaf water deficit in sensitive varieties, although these varieties also showed a markedly lower daytime 1/rL in the glasshouse as compared with resistant varieties.
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