摘要:
为科学制定栓皮栎播种苗氮肥管理措施，在砂培条件下，采用指数施肥的试验方法，设置4个供氮水平（0、120.6、216.4和329.2 mg/(株•a）），探求不同的供氮水平对栓皮栎播种苗光响应特征曲线的影响。结果表明，在苗木生长的不同阶段，供氮量的差异对叶片光响应曲线的影响有所差别。生长初期，氮素对栓皮栎播种苗光响应特征曲线参数的影响不显著。速生期，缺氮（0 mg/(株•a））严重影响苗木的光合性能，导致栓皮栎播种苗的光饱和点（LSP）、最大净光合速率（Pmax）、表观量子效率（α）偏低，而光补偿点(LCP)偏高；当供氮量从120.6 mg/(株•a）增大到216.4 mg/(株•a）时，苗木Pmax并没有明显变化，但苗木的LCP降低，LSP升高；过量供氮（329.2 mg/(株•a））反而导致叶片的光合性能下降。生长末期，在其他处理苗木叶片光合性能均有不同程度下降的情况下，216.4 mg/(株•a）水平的苗木仍然保持着相对较高的光合能力。
Abstract:
In order to provide a theoretical foundation for nitrogen fertilizer management of Quercus variabilis seedlings, using exponential nitrogen fertilization regimes, the effects of nitrogen treatments on light-response curves of Q. variabilis seedlings were studied under sand-cultured condition. The seedlings were planted in pots, supplied with four nitrogen application levels (0, 120.6, 216.4 and 329.2 mg/(seedling•year)). The results show that various nitrogen application levels had different effects on the light-response curves of Q. variabilis leaves, depending on the growth phases. At the initiation phase, all the simulation parameters of light-response curves showed no significant differences among treatments. At the fast-growth phase, the lack of nitrogen weakened the photosynthetic capability of seedlings in treatment CK (0 mg/(seedling•year)) sharply, which reduced the light saturation point (LSP), maximum net photosynthetic rate (Pmax) and the apparent quantum efficiency (α); meanwhile, the light compensation point (LCP) expressed a trend of increase. When the nitrogen level was raised from 120.6 to 216.4 mg/(seedling•year), no significant variation about Pmax was found between the two treatments; however, the LCP of the seedlings in 216.4 mg/(seedling•year) treatment was lower and the LSP was higher. Yet, excessive nitrogen supply (329.2 mg/(seedling•year)) played a negative role on the photosynthetic ability of Q. variabilis seedlings. At the later phase, relatively higher photosynthetic efficiency was maintained in the seedlings in 216.4 mg/(seedling•year) treatment, comparing with the common decline in other three treatments.
百度学术
下载:
