Co-Authors:
Plaut, Z., Inst. Soil, Water and Environ. Sci., Agricultural Research Organization, Volcani Center, P.O. Box 6, Bet-Dagan 50250, Israel
Magril, Y., Du-Kedem Projects Ltd., Hazayit st. 8, Gan-Haim 44910, Israel
Kedem, U., Du-Kedem Projects Ltd., Hazayit st. 8, Gan-Haim 44910, Israel
Abstract:
Water vapour conductance and CO2 fixation rates were simultaneously measured in leaves of pepper, tomato, apple, mallow, and honeysuckle plants sprayed with a new acrylic type film-forming material distributed in Israel as "Magen 2001". Plants were fully supplied with water and not exposed to water stress from before spraying until the time of measurement. Water vapour conductance was decreased significantly more than CO2 fixation in all tested species, except in one cultivar of apple in which neither water vapour conductance and CO2 fixation rates were affected. The material was found to be fully active for about 30 d after application, and its efficacy started to diminish 36 d after application. The relationship between CO2 fixation and water vapour conductance over the entire range of conductances was found to be exponential with R2 values in the range of 0.732-0.858. The much smaller change in CO2 fixation as compared with water vapour conductance at high conductances suggests that mesophyll conductance served as an important control of CO2 fixation. The difference in response of water vapour conductance and CO 2 fixation was thus attributed to mesophyll conductance, which had no effect on water vapour conductance. It was also shown that mesophyll conductance was not affected by the intercellular space CO2 concentration, and was probably mainly determined by species. The ratio between water vapour conductance and CO2 fixation can serve to screen film-forming materials and to evaluate their suitability for different crops and cultivars.
תפריט נגישות
ניגודיות עדינה
מונוכרום
הדגשת קישורים
חסימת אנימציה
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