Physiological variations of Assam, China and Cambod varieties of tea (Camellia sinensis L.)

Abstract

Based on diversity and phenotypic characters the tea plants are broadly classified as Assam, China and Cambod varieties. The monthly mean of photosynthesis (Pn) of Assam (TV2), China (TV7) and Cambod varietis (TV22) was 6.28, 6.68 and 8.34 μmol CO2 m^-2s^-1 respectively. All clones assimilated more CO2 in the month of September. Highest carbon was assimilated by Cambod and lowest by Assam variety while China variety showed an intermediate type in carbon assimilation efficiency. Transpiration loss (E) of TV2, TV7 and TV22 was 4.41, 3.58, 3.82 mmol m^-2s^-1 respectively. Highest E 5.51 mmol m^-2s^-1 was in the month of July. Higher transpiration correlates with higher light intensity of the month. Water use efficiency (WUE) of Cambod clone TV22 was highest (2.44μmol/mmol m^-2s^-1) as compared to Assam variety TV2 (1.68 μmol/mmol m^-2s^-1) and China variety TV7 (2.17 μmol/mmol m^-2s^-1). Assam variety TV2 had the least WUE. High WUE of a variety confers better tolerance to drought as it can conserve more water in its cells to maintain high leaf water potential to regulate the metabolic activities during soil moisture stress. Light intensity (Photosynthetic photon flux density: PPFD) and leaf temperature of corresponding Pn, E and WUE were estimated and discussed. Considering the metabolic activities of photosynthesis, water use efficiency and transpiration loss it can be inferred that Cambod variety is more efficient for biosynthesis of carbohydrates.