| Abstrakt: |
Cotton plants were grown in late spring under full sunlight in glasshouses containing normal ambient partial pressure of CO (32±2Pa) and enriched partial pressure of CO (64±1.5Pa) and at four levels of nitrogen nutrition. Thirty-five days after planting, the total dry weights of high CO-grown plants were 2- to 3.5-fold greater than plants grown in normal ambient CO partial pressure. Depending on nitrogen nutrition level, non-structural carbohydrate content (mainly starch) in the leaves of plants grown in normal CO was between 4 and 37% of the total leaf dry weight compared to 39 to 52% in the leaves of high CO-grown plants. Specific leaf weight calculated using total dry weight was 1.6- to 2-fold greater than that based on structural dry weight. In high CO-grown plants the amount of non-structural carbohydrate translocated from the leaves at night was between 10 and 20% of the level at the end of the photoperiod. This suggests that the plant was unable to utilize all the carbohydrate it assimilated in elevated CO atmosphere. While there was a 1.5-fold enhancement in the rate of CO assimilation in plants grown in 64 Pa CO, there was, however, some evidence to suggest that the activities of other metabolic pathways in the plants were not stimulated to the same extent by the enriched CO atmosphere. This resulted in massive accumulation of non-structural carbohydrate, particularly at low level of nitrogen nutrition. [ABSTRACT FROM AUTHOR] |
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