| Bamboo, a typical vegetatively propagated clonal plant belonging to Gramineae Bambusoideae, regenerated by base of sympodial bamboo buds or scattered bamboo rhizome lateral buds. The buds sprout and growth are regulated by many factors including nutrients and phytohormones. Soluble sugar, nitrogen and phosphorus are important parts of nutrients, and strigolactones( SLs), a novel class of phytohormone inhibiting lateral buds growth and development, may be involved in the regulation of bamboo lateral buds.In this research, seasonal change of nutrients in Phyllostachys edulis rhizome and leaf were monitored to explore the requirement characteristics for sprout and growth of bamboo rhizome lateral buds. GR24,an artificial analogs of strigolactone, was applied to bamboo seedlings to investigate its response to SLs; A SLs receptor gene Pe D14 from Phyllostachys edulis was cloned, and its genetic structure and tissues expression were analyzed; Finally, endogenous 5-DS was determinated by reversed-phase ultra performance liquid chromatography( RP-UPLC), and the determination method for bamboo was preliminarily established. The main research results were as follows:1. Soluble sugar content in bamboo leaf and rhizome were low in Jul and Oct, then significantly increased 103.6 % and 52.8 % in Jan, respectively, while decreased in Apr lightly. Changing trends of Nitrogen and phosphorus contents in bamboo leaf and rhizome were similar, decreasing in Oct and increasing Jan, then falling back in Apr, variation amplitude were gentle except phosphorus content of rhizome.2. GR24( 5 μM) was applied to Bambusa oldhami seedlings, which indicated that bud average amount of treatment decreased 95.83 % and 78.43 % after 2 weeks and 4 weeks respectively, compared with control.3. The full-length of Pe D14 cloned from Phyllostachys edulis, which contained a 918 bp introns coding 305 amino acids. Real-time PCR were conducted to investigate the tissue-specific expression of Pe D14, which showed that Pe D14 was strongly expressed in buds and least in rhizome.4. In the tertiary structure of Pe D14, there were 7 β-extended strand core surrounded by 7 main alpha helis, and 4 alpha helis on the top. The tertiary structure of Pe D14 included a Ser-His-Asp triplet hydrophobic cavity, and its catalytic triplets was located in Ser134, Asp255 and His284. Sequence comparison showed that there were more than 87 % similarity with monocotyledons and more than 60 % similarity with dicotyledons. 34-50 amino acids sequence were found in N-terminal of monocotyledons but not in dicotyledons.5. 5-DS in bamboo was measured by ultra performance liquid chromatography( UPLC), which showed that a maximum absorption but severe peak spreading and baseline drift under 237 nm, and good peak shape and baseline under 250 nm. Using methanol as mobile phase got a steadier baseline than acetonitrile, and adding 0.25 % formic acid into mobile phase can help improve the peak shape. Ultrasonically assisted extraction with ethyl acetate could not only minimize extraction time but also raise the percentage of extraction; Solid-phase extraction and purification could effectively reduce interference from noise peaks. Methodological investigate showed that detect limit, precision, stability, repeatability of method can meet the requirement of analysis. Contents of 5-DS from different bamboo shoots varies from 11.27 to 51.17 ng·g-1(FW), contents of 5-DS in bamboo root was the largest, and shoots the least. |
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