金花茶回归苗木的生长、光合特性和叶片形态特征

Growth, Photosynthetic Characteristics and Leaf Morphological Characteristics of Camellia nitidissima Reintroduction Plants

关键词:  金花茶  回归引种  实生苗  扦插苗  光合生理特性  叶片解剖结构

Key words:  Camellia nitidissima  reintroduction  seedlings  cutting seedlings  photosynthetic physiological characteristics  leaf anatomical structure

摘要:

金花茶（Camellia nitidissima）为国家二级重点保护野生植物，具有重要的观赏、药用和科研价值，但其野生资源遭到极为严重的破坏，有濒临灭绝的风险，因此开展金花茶的回归引种，可有效保护该物种。为探究金花茶实生苗、扦插苗回归引种到原生境近7年后在生长和光合生理特性方面的差异，本研究对其生长状况、成活率、光合特性和叶片形态特征等进行测定。结果表明：金花茶回归苗木实生苗比扦插苗具有更大的生长量和更高的成活率；实生苗最大净光合速率（P_max）、光饱和点（LSP）、表观量子效率（AQY）均显著高于对应点的扦插苗（P<0.05），其光能利用范围也大于对应点的扦插苗；实生苗的叶绿素a （Chl a）、叶绿素b （Chl b）和类胡萝卜素（Car）含量均显著低于对应点的扦插苗（P<0.05），但叶片厚度、海绵组织厚度、中脉导管直径和叶面积则均显著大于对应点的扦插苗（P<0.05）；双因素方差分析结果表明，回归点和苗木类型分别对金花茶的株高、地径、成活率、P_max、LSP、叶绿素含量和叶面积均有极显著影响（P<0.01）。因此，在开展金花茶回归引种中宜优先选用实生苗种植，并选择具有中等遮阴环境的野外生境进行回归。

Abstract:

Camellia nitidissima is a national second-level key protected wild plant with important ornamental, medicinal, and scientific value.However, its wild germsplasms have been severely damaged at risk of extinction.Therefore, reintroducing of C.nitidissima can effectively protect this species.To investigate the differences in growth and photosynthetic physiological characteristics of C.nitidissima seedlings and cutting seedlings after reintroduction to their original habitat for nearly seven years, we measured their growth status, survival rate, photosynthetic characteristics and leaf morphological.The results showed that the growth and survival rate of the seedlings were higher than that of the cutting seedlings.The seedlings exhibited significantly higher values for maximum net photosynthetic rate (P_max), Light Saturation Point (LSP) and Apparent Quantum Efficiency (AQY) compared to the cutting seedlings(P<0.05).Additionally, the seedlings had a wider range of light energy utilization than the cutting seedlings.The chlorophyll a (Chl a), chlorophyll b (Chl b), and carotenoid (Car) contents of seedlings were significantly lower than those of cutting seedlings(P<0.05), while the leaf thickness, spongy tissue thickness, mid vein catheter diameter and leaf area were significantly higher than those of cutting seedlings (P<0.05).The results of two-factor ANOVA showed that reintroduction point and seedling type had significant effects on plant height, ground diameter, survival rate, P_max, LSP, chlorophyll content and leaf area of C.nitidissima, respectively (P<0.01). It is advisable to prioritize the planting of live seedlings and to select field habitats with medium shade for the regression of C.nitidissima.