遮光和施氮对暗紫贝母形态特征和生物量分配的影响

根据最优分配理论( optimal partitioning theory,OPT),在自然环境中,由于地上和地下资源在空间上的分离,陆生植物需要调整其地上和地下部分的生物量分配以平衡对资源的吸收。研究结果[1-2]显示：在植物地上资源严重受限时,叶片的生物量分配相对增加；而地下资源严重受限时,根的生物量分配相对增加。然而,植物的生物量分配对资源的响应较为复杂。首先,除了生物量分配,形态变化也是植物调节资源吸收的重要手段,例如,植物通过增加比叶面积提高对光照的吸收,通过调整比根长响应土壤养分的变化[3-4]；并且,一些植物甚至以形态响应为主,生物量分配的变化并不明显[3,5]。此外,某些植物还有一些特殊的资源平衡方式,例如,克隆植物通过构件之间的养分传输平衡资源在空间上的分配不均[6]；拥有特化储藏器官的植物可依靠大量储藏物质来平衡资源在时间上的分配不均[7]。植物所具有的丰富的资源响应方式决定了其多样的资源策略。

Effects of shading and applying nitrogen on morphological characteristics and biomass allocation of Fritillaria unibracteata

Changes in morphological characteristics and biomass allocation of Fritillaria unibracteata P. K. Hsiao et K. C. Hsia under conditions of shading and applying nitrogen were studied. The results show that leaf area, specific leaf area, specific root length, ratio of dry weight of above-ground part to that of under-ground part ( R1 ) , ratio of dry weight of leaf to that of root ( R2 ) and ratio of dry weight of leaf to that of whole plant ( R4 ) of F. unibracteata under condition of shading have extremely significant differences with those of the control (P<0. 01), but root surface area and ratio of dry weight of root to that of whole plant ( R3 ) have no significant differences with those of the control. Under condition of applying nitrogen, specific leaf area and R4 have extremely significant differences with those of the control, R1 has significant difference with that of the control (P<0. 05), but leaf area, root surface area, specific root length, R2 and R3 have no significant differences with those of the control. Comprehensive analysis result shows that treatments of shading and applying nitrogen have some effects on morphological characteristics and biomass allocation of F. unibracteata, but response of root to shading and applying nitrogen are weaker than those of leaf.