Abstract:
Objective Effects of endogenous hormones and expressions of genes related to the hormone syntheses on the morphology and physiology of bikequ yam (Dioscorea Opposita) tubers during expanding stage were investigated. Correlation between the indicators was established to provide guidelines for upgrading the yield and quality of the yam farming.
Method During expansion stage of the tubers, contents of starch, reducing sugar, and soluble total sugar were determined by chemical analysis, those of endogenous ABA, GA3, IAA, JA, ZR, and IPA by enzyme-linked immunosorbent assay, and that of salicylic acid (SA) by HPLC. Correlations between these indicators were tested by regression analysis. The gene expression levels of endogenous hormone related genes were obtained by transcriptome sequencing.
Result The contents of IAA, ZR, ABA, JA, and SA correlated positively with the morphological indices on the tuber, while those of GA3 and IPA correlated negatively. IAA correlated with the tuber perimeter and diameter. GA3 correlated inversely with the length of tuber. The IAA-related gene was found to negatively correlate with IAA in the tubers.
Conclusion Among the endogenous hormones, IAA, ZR, ABA, JA, and SA promoted the tuber enlargement; GA3 and IPA inhibited the growth; IAA enhanced the girth increase; and, GA3 retarded the elongation. The downregulation of IAA-related gene increased the hormone synthesis. In other words, the gene could regulate the IAA production in the yams, and in turn, affected the tuber growth.
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