Effects Of Chlorpropham Treatment On Potato Bud Inhibiting And Its Partial Mechanism

Sprouting during potato tubers storage is a one of difficult problems limiting potato tubers storage technology. In this study, potato tubers (varieties:Longshu NO.3; Longshu NO.7) were treated with chlorpropham (CIPC) emulsifiable solution. Effect on starch, protein, vitamin C etc in potatos during storage was analysed. In addition, residual content of CIPC in potato tubers was examined. The difference of endogenous hormone content from potato tubers dormancy to buds growth was compared. Obtained research results are as followings:1. CIPC treatment may significantly inhibited potato tubers sprouting and bud growth. In untreated control group, all potatos (Longshu NO.3) sprouted after120days of room temperature storage, and germination percentage of potatos (Longshu NO.3) was84%after120days of low temperature storage. However, in CIPC-treated group, germination percentage of potatos (Longshu NO.3) was4%and zero. Similar results happened to potatos (Longshu NO.7). After120days of room temperature storage, weight loss of CIPC-treated potato tubers (Longshu NO.3) was25%of untreated control group.2. Analysis of nutritional components in CIPC-treated potatos showed that CIPC treatment could effectively sustain starch and protein content, decrease vitamin C loss, and delay reducing sugar increase in potato tubers, keep better commercial properties and processing quality during storage.3. CIPC treatment significantly inhibited respiration of potatos. During the late period of storage, respiration rate of buds in potato tubers was20%of that of untreated control ones. Results showed that two kinds of plant endogenous hormones, IAA and GA3, were inhibited in CIPC-treated potato tubers. At the end of natural dormancy period, IAA and GA3content slowly increased. There was marked difference in IAA and GA3content between CIPC-treated group and untreated control group. ABA content in CIPC-treated potato tubers was only detected during the initial stage of storage, but couldn’t be detected during the interim and later period.4. Analysis of CIPC residual content in potatos showed that CIPC residual content was the highest in potato peels. During different storage period, CIPC residual content may be decreased by removing the peel. In short-period (30days) of storage, CIPC residual content in potatos was below2mg/kg. In long-period (120days) of storage, CIPC residual content in potatos was only0.5mg/kg. The content is by far below the standard content (30mg/kg) issued by FAD.5. CIPC in potato tuber sprout inhibition effect significant for tuber quality has a positive role in maintaining the use of low residue, is a high efficiency and low toxicity of potato sprout inhibition agent. Sprout inhibition effect may be achieved by the delay tuber starch hydrolysis through inhibition of the two hormones, IAA, GA3, and inhibition of tuber respiration.