| In order to find the growth response on nitrogen fertilizing for the breeding of Taxus cuspidata, six-year-old seedlings were taken as experimental materials to study the fertilizing effects of foliar nitrogen on growth, leaf nitrogen content, chlorophyll content and photosynthetic characteristics. The seedlings were treated with 3 nitrogen levels (0.5‰, 1‰, 1.5‰) and 3 nitrogen forms which were urea, nitrate-nitrogen and ammonium nitrogen. The results showed that the growth of seedlings treated with nitrogen were better than the seedlings treated with water (CK), and the branch growth with 1‰ urea treated was 39.1% longer than that of CK (P< 0.01). Leaf nitrogen content and chlorophyll content of all nitrogen treated seedlings increased obvously, the seedlings with 1.5‰ urea treated had the highest nitrogen content which was 20.0% higher than CK (P< 0.01), total chlorophyll content and chlorophyll a content of the seedlings with 1‰ urea fertilized were 20.5% and 27.1% higher than that of CK respectively (P<0.01). The seedlings treated with nitrogen had better photosynthetic indexes than that of CK (except the seedlings with 1.5‰ ammonium sulfate) including the net photosynthetic rate (Pn), the maximum net photosynthetic rate (Pmax), apparent quantum efficiency (AQY) and light saturated point (LSP), and Pmax of seedlings treated with 1‰ urea improved by 62.0%(P<0.01) compared with CK. In general, total chlorophyll content and Pmax of seedlings showed an increasing trend following leaf nitrogen content increased, and 1‰ urea treatment had the best result, there was no obvious difference between nitrate-nitrogen and ammonium nitrogen treatment. |
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