Investigation of Influence of Photoperiod and Light Intensity on Seed Germination and Seedling Growth of St. John's Wort (Hypericum perforatum L.)

Abstract

The germination rate and seedling growth of St. John's wort (Hypericum perforatum L.) have been investigated under 5 photoperiods and 3 light intensities, respectively. The results reveal that the best photoperiod condition for the germination rate of H. perforatum is dark: light=18h: 6h. The germination rate of H. perforatum under this condition can reach 72 % on 21(superscript th) day after sowing. Germination rate of H. perforatum are all above 60 % on 21(superscript th) day after sowing under different conditions of light intensity. Among them, 150 μ mole photons m^(-2) s^(-1) is the best condition for germination of H. perforatum. The germination rate of H. perforatum of above-mentioned condition reaches 73 % on 21(superscript th) day after sowing. The results of seedling growth have shown that 12h/12h and 6h/18h (dark: light) are better conditions than other 3 treatments and the best condition of different light intensities is 350 μ mole photons m^(-2) s^(-1). The fresh weight of H. perforatum reaches 62 g after 6 months.聖約翰草分別利用5種光週期以及3種光強度進行種子發芽與種苗生長試驗，種子發芽試驗結果顯示，不同光週期試驗以18小時黑暗及6小時光照處理種子的發芽率最佳，於第21天後發芽率可達72%。不同光強度的試驗於第21天後發芽率都在60%以上，其中以150μ mole photons m^(-2)s^(-1)處理種子的發芽率最佳，於第21天後發芽率可達73%。種苗生長試驗結果顯示，不同光週期的試驗以12小時黑暗及12小時光照處理與6小時黑暗及18小時光照處理的生長狀態較其他3種處理為佳，不同光強度的試驗以350μ mole photons m^(-2)s^(-1)生長狀態最佳，6個月後植物鮮重可達62公克