Seasonal Changes of the Total Nonstructural Carbohydrates and Total Nitrogen Contents in Vines and Leaves of Kiwifruit Plants (Atinidia chinensis Planch) cv. Bruno

Abstract

Seasonal changes on the carbohydrates and nitrogen contents in leaves and vines of kiwifruit plants. cv. Bruno, grown at the Royal Ang Khang Station, Amphur Fang, Chiang Mai Province, were investigated between the period of September 1981 to August 1982. It was found that seasonal changes on the carbohydrate contents followed the same pattern as those of other temperate woody plants. The maximal peak of carbohydrate contests in the form of reducing sugars in vines were found at the end of the dormant season in February (49.09 mg/g). Carbohydrates in the form of total nonstructural carbohydrates (TNC) were at maximum when the buds burst in March (57.08 mg/g). Both forms of carbohydrates were at the lowest level in August ( 8.39 and 9.82 mg/g , respectively). In leaves, both forms (reducing sugars and TNC) were at the highest when the leaves mutured in October ( 31.64 and 33.40 mg/g, respectively), and were at the lowest level during the earlier stage of leaf development in May ( 7.3 and 11.91 mg/g, respectively). Total nitrogen contents varied with the growth phase. In vines, the contents did not differ during August to February ( 6.35 and 8.58 mg/g ). The contents were high during the early stage of new shoots (March to May). The highest level was in March (12.0 mg/g ). The contents in leaves were at the highest level in June ( 39.68 mg/g ) when the leaves were young, As the leaves aged the nitrogen contents declined and reached the lowest level in November ( 28.37 mg/g ).