COMPARATIVE STUDY OF TRANSPIRATION RATES BY DIFFERENT EUCALYPTUS SPECIES UNDER VARIOUS SOIL MOISTURE AND CLIMATIC CONDITIONS

摘要

The seedlings of 10 Eucalyptus species were grown in pots for about 46 weeks under variable soil moisture regimes. The average transpiration rate during November was 130 g day_(-1) plant_(-1), which varied significantly among different species. E. urophylla and E. grandis had the highest transpiration rate with 180 and 165 g day_(-1) plant_(-1), respectively. On the other hand, E. ochrophloia had the lowest value of 65 g day_(-1) plant~(-1). On an average, the water loss from E. urophylla and E. grandis was 2.0 to 3.0 times more as compared to E. ochrophloia. Almost the same trend was observed for transpiration rate during the month of June. However, value of transpiration rate was higher during June as compared to November. The significant effect of soil moisture on transpiration rate was also observed. In general, higher transpiration was recorded under flooding treatment and the same decreased continuously with decrease in soil moisture. Transpiration rate was closely related with total leaf surface area as noted during both the times observations.