[Effects of light intensities endogenous hormones of Bletilla striata during acclimatization]

The effect of light intensities on the endogenous hormones of Bletilla striata during seedling acclimatization was studied in order to explain the mechanism and provide basic data for conservation and cultivation of this wild medicinal species.

The samples was treated with three photosynthetic photon flux densities: 3 000, 6 000, 12 000 lx during the acclimatization stage to study the hormone dynamic changes of IAA, ABA, GA3.

Endogenous IAA concentration was declined in all treatments and the lowest level in all treatments was the middle light intensity. A sharp increase of endogenous ABA concentration in a short period, the concentration was increased by 380.2% in middle light (320.8 ng x g(-1)). Endogenous GA3 concentration was declined especially in the high light treatment. At 10 days of acclimatization the GA3 concentration was decreased by 52.2% in the high light (473.6 ng x g(-1)).

Endogenous hormones concentration could be rapidly changed by the light, and endogenous ABA concentration could be sharply increased when acclimatization in middle light intensities.