Photosynthetic Characteristics of Vitis vinifera x V. labrusca 'Campbell Early' Grapevine Cultivar under Flooding Condition

摘要

Abstract. Photosynthetic characteristics of 'Campbell Early' grapevine cultivar under flooding condition were examined with respect to gas exchanges and potential quantum yield (Fv/Fm). With increasing flooding duration, net CO_2 assimilation rate (Aco2), stomatal conductance (gs), and transpiration rate (E) decreased. Aco_2 of non-flooded plants in late June was 14.4 mu mol-m~(-2)-s~(-1) at 1,000 mu mol-m~(-2)-s~(-1) photosynthetic photon flux and maintained without any change for 3 days after flooding. At 7 and 14 days after flooding, however, the values significantly decreased to 78 and 58%, respectively, and were not readily recovered. gs and E were reduced in parallel with that of Aco_2, indicating that Aco_2 and E were greatly affected by g_sin 'Campbell Early' grapevine cultivar. Flooding also decreased apparent quantum yield, light saturation point, and maximum CO_2 assimilation rate, implying that photosystem II (PSII) was impaired. This observation was confirmed by the decreases of Fv/Fmvalues and chlorophyll contents. At 3 days after flooding, the Fv/Fm value in flooded plants was significantly lower than that in non-flooded plants. Chlorophyll contents also decreased continuously with increasing flooding duration and then the leavesvisualized chlorosis. In conclusion, flooding decreased photosynthesis of 'Campbell Early' grapevine cultivar and ultimately injured PSII reaction center by closing stomata, reducing transpiration, and accumulating photosynthetic energy.