科研之友
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摘要
Stem reorientation in response to inclination in trees has commanded the attention of the research community widely, but the molecular mechanisms of the response are still unknown. The most accepted theory is auxin redistribution in affected tissues. Flavonols have been reported as potent inhibitors of polar auxin transport; however, no reports have shown differential modulation by flavonols within the trunk. Here, transcriptional, microscopic, and chemical approaches were used to analyze the contents of flavonoids in 45 degrees inclined radiata pine seedlings. A time course was established and samples obtained by cutting stems into apical, medial, and basal segments or by longitudinal dissection into upper and lower halves to determine polar distribution of flavonoids. The expression analysis of PrCHS, PrF3H, and PrFLS indicated induction in response to inclination; higher transcript levels were recorded at the basal zone and in the upper half of the stem. A reduction in abundance of PrARP transcripts in addition to immunospecific auxin detection at the lower half of inclined stem was found. Concomitantly, quercetin and kaempferol accumulated in the upper stem half. Our results suggest that stem reorientation is a response to a concerted and differential mechanism that modulates imbalance of auxin distribution in one side of the stem.
- 出版日期2016-6
