| Most varieties of pumpkin (Cucurbita moschata (Duch. ex Lam) Ouch, ex Poiret) in China have long vines, while 'Non-vine I' is one of the few dwarf pumpkin varieties without long vines. Practically, dwarf varieties of gourd vegetable crops are very valuable because they need less ground area and manpower. So, dwarf phenotype of gourds is very important in practice. Main studies on pumpkin were focused in its nutrition and genes which code gibberellin (GA) synthases. And no study was carried out on dwarf pumpkin. So, studies on dwarf phenotype of 'Non-vine l' are important not for practice but enrich basal academic information on gourds. In this study, we observed and compared of the phenotypes of dwarf and normal pumpkin 'yellow-wolf, compared effects of gibberellic acid (GA3), brassinolide (BL), 1 -naphtlalene acetic acid (NAA) on vine elongation of dwarf with the aim of determining which hormone is related to dwarf phenotype, and analyzed Ihe physiological effect of GA3 and its inhibitor paclobutrazol (PP333) on dwarf pumpkin to determine its sensitivity to GA and its inhibitor. On the basis of that, we analyzed the induced-expressed genes by GA in dwarf pumpkin internodes by cDNA-AFLP technique. The main results are as follow:(1) Observation of two varieties plants phenotypes showed that dwarf pumpkin 'Non-vine 1' plants appeared to differ in their gross morphology, primarily in the length of their internodes compared normal pumpkin 'Yellow-wolf' plants. Feed experiment with different hormones GA3, BL and NAA revealed that 0.15 mM and 0.6 mM GA3 could promote the elongation of vines in dwarf pumpkin. Curves of GA3 dose-responses of dwarf pumpkin showed that the effect of GA3 on vine elongation of 'Non-vine F plants was enhanced with the increase of GA3 concentration at the range of 0.15 mM to 1.2 mM, but the enhancing effect was less significant at concentrations higher than 0.6 mM. GA3 of this concentration range can also slightly stimulate elongation of petioles of dwarf plants 15 days after treatment Anatomical analysis of the effects of GA3 on vine length of dwarf pumpkin showed that the average cell size in 'Non-vine F plants is significantly smaller than in those of normal plants and in 'Non-vine 1' plants treated with GA3, and GA3 induced cells elongation of internodes in dwarf pumpkin.(2) Treatment with GA3 could improve the activity of α-amylase, catalase, peroxidase and acid phosphatase in dwarf pumpkin. At the range of 0.15 mM to 1.2 mM GA3, the improvement effect of 0.3 mM GA3 on catalase and acid phosphatase activity was most significant; the improvement effect of 0.6 mM GA3 ona-amylase was most significant; and peroxidase acitivity appeared insensitive concentrations of GA3. The activity of α-amylase, catalase, peroxidase and acid phosphatase in dwarf pumpkin internode were strongest on 3 d, 3 d, 9 d and 6 d after treatmentwith 0.6 mM GA3, respectively.(3) Feed experiment with paclobutrazol and GA3 showed that (a) dwarf pumpkin was sensitive to paclobutrazol, its growth was inhibited by paclobutrazol, including hypocotyls shorten and plants shorter; (b) paclobutrazol inhibited the activity of α-amylase, catalase, ascorbat peroxidase and acid phosphatase in dwarf pumpkin; (c) paclobutrazol also inhibited the growth and the enzymes activity in normal pumpkin, as in dwarf pumpkin; (d) GA3 could restrain the inhibition effect of paclobutrazol on growth and the enzymes in dwarf and normal pumpkin.(4) The 256 random primers were screened by cDNA-AFLP in order to seeking regulated-expression genes by GA3, and there were 26 000 TDFs (Transcript derived fragment) between 50-600 bp. Among, 141 TDFs were regulated by GA3, of which 84 TDFs were up-regulated by GA3 and 57 TDFs were down-regulated by GA3. 53 TDFs were cloned, of which 32 and 21 TDFs were up-regulated and down-regulated by GA3 respectively. By BLAST in the GeneBank, 3 1TDFs sequences are similar to known genes or EST in Genebank, respectively, and other 22 TDFs are no similar to any genes or EST in Genebank. The TDFs similar to known genes could cl... |
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