Effects of Chlorocholine Chloride on Phytohormones and Photosynthetic Characteristics in Potato (Solanum tuberosum L.)

Effects of chlorocholine chloride (CCC) on phytohormones and photosynthetic characteristics of Zhongshu 3, a potato (Solanum tuberosum L.) variety widely cultivated in south China, were studied by foliar CCC application on 24 and 28 days after emergence, that is, at the tuber initiation stage. It was found that on 42 days after emergence, that is, at the tuber bulking stage, spraying CCC increased indolacetic-3-acid (IAA) and zeatin (Z) contents but decreased abscisic acid (ABA) content in leaves. The content ratios of IAA/Z, IAA/ABA, Z/ABA, and (IAA + Z)/ABA in leaves treated with CCC were higher than those of the control. CCC plays a prominent regulating role in the photosynthesis of Zhongshu 3. The net photosynthetic rate (P (n)), stomatal conductance (G (s)), intercellular CO2 concentration (C (i)), and transpiration rate (T (r)) of treated leaves were superior to those of controls at the tuber bulking stage. CCC markedly increased tuber yield and quality. The contents of sucrose and starch in tubers treated with CCC increased at the end of the vegetation period, whereas the contents of reducing sugars and solanine decreased. CCC at 2.0 g L-1 was found to be the most effective concentration. Collectively, the results of this research identify phytohomonal metabolism and photosynthetic physiology of potato leaves as processes affected early after application of CCC resulting in significantly improved increases in tuber yield and quality.