Carbon-dioxide and water vapor exchange, malate content and delta-carbon-13 labeled value in Cicer arietinum grown under two water regimes

Winter, K.

Zeitschrift für Pflanzenphysiologie 101(5): 421-430


Chickpea (C. arietinum L.) was grown under high and low soil moisture conditions and .delta.13C value, the daily course of CO2 and water vapor exchange and nocturnal change in malate content were determined. Plants from both treatments exhibited solely C3 photosynthetic CO2 fixation and in contrast to a previous report (Santakumari, et al, 1979), did not exhibit features of Crassulacean Acid Metabolism. At low moisture conditions plants showed a higher water-use efficiency as indicated by an increased ratio of CO2 assimilation to transpiration. Photosynthesis in these plants proceeded at a lower intercellular partial pressure of CO2 than in well irrigated plants. Water stress resulted in .apprx. 2.permill. less negative .delta.13C values. A similar shift in .delta.13C value in response to water stress was obtained for Gossypium hirsutum. This change in .delta.13C value is possibly due to an increased influence of diffusional fractionation of C isotopes during photosynthetic CO2 uptake.