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摘要
The effects of silver thiosulfate (STS) and naphthalene acetic acid (NM) (0.45% NAA + 1.2% NAA-amide at 500 mg L-1) on flowering bud development, anthesis duration, bract longevity, and bract photosynthetic rate were studied in Bougainvillea spectabilis 'Killie Campbell' plants, under interior conditions. The relationships between bract longevity and the above parameters were also investigated.
NAA induced longer bract longevity, shorter flower anthesis duration, and lower percentage of flowers reaching anthesis. STS alone increased duration of flower anthesis but did not affect completely developed bract abscission. as compared to the water treatment. Depending on the experiment, adding STS to NM delayed or had no effect on bract abscission. Longer bract longevity was related to shorter flower anthesis and lower percentage of flowers reaching anthesis. Manual removal of flowers from the bract + flower unit increased bract longevity. Despite the low level of irradiance, bracts photosynthesized and plants treated with NM (alone or with STS) had lower bract photosynthetic rates. Bract photosynthetic activity. although with relevant rates (similar to leaves and most probably capable of covering respiration expenditure) did not seem important as an energy source for bract longevity since bracts that lasted longer had lower photosynthetic rates. In the water control, percentage of flowers reaching anthesis positively correlated with bract photosynthetic rates.
In potted bougainvillea under low light conditions, flower senescence and bract abscission are under different types of control. In addition to the classical effect of auxin reducing ethylene production, and/or sensitivity of the abscission zone to ethylene. NM delays bougainvillea bract abscission via early interruption of flower development.
- 出版日期2012-12
