光照强度对3种金花茶光合生理特性及生物量的影响

Effects of Light Intensity on Photosynthetic Physiological Characteristics and Biomass of Three Yellow Camellia Species

关键词:  金花茶  光照强度  叶绿素  光合特性  生物量

Key words:  Yellow Camellia Species  Light intensity  Photosynthetic characteristics  Biomass

摘要:

四季花金花茶（Camellia perpetua）、淡黄金花茶（Camellia. flavida）和东兴金花茶（Camellia tunghinensis）隶属金花茶组植物，为国家二级重点保护野生植物，这3个物种分布范围狭窄，野生资源濒临灭绝，探索其对不同光环境的适应性，寻找其适宜的生长光强，可为这3种金花茶的人工繁育、种群恢复及迁地保护提供理论依据，也可为其野生种群生境差异的原因提供部分解释。方法：本研究以此3种金花茶3年生扦插苗为试验材料，采用人工遮荫方法研究不同光照强度（8%、20%、45%、100%）对其光合生理特性和生物量的影响。结果：（1）3种金花茶在低光照环境下有较大的最大净光合速率（Pmax）、表观量子效率（AQY）、最大荧光（Fm）、最大光化学效率(Fv/Fm)、实际光化学效率（ΦPSII）和光合电子传递速率（ETR），表明其对低光照环境有较好的适应性。（2）四季花金花茶的Pmax在45%光照强度下仍保持较高水平，且光饱和点（LSP）随着光照强度的增加呈升高趋势；而淡黄金花茶和东兴金花茶的Pmax和LSP随光照强度的增加先升高后降低，均在20%光照强度下达到最大值。（3）随着光照强度的增加，3种金花茶叶片叶绿素总量（Chl）、叶绿素a（Chla）、叶绿素b（Chlb）和类胡萝卜素（Car）含量降低，Car/Chl值升高，Cha/Chb值先降低后升高。（4）3种金花茶根、茎、叶生物量和总生物量均随着光照强度的增加而表现为先升高后降低，其中四季花金花茶在45%光照强度最高，而淡黄金花茶和东兴金花茶则在20%光照强度下最高。结论：四季花金花茶对于强光的耐受性更强，淡黄金花茶次之，东兴金花茶最弱；四季花金花茶喜中等光照环境（45%光照强度），而淡黄金花茶和东兴金花金花茶偏好低光照环境（20%光照强度）；3种金花茶的光合特性符合其野生种群的分布地光环境特征。

Abstract:

Camellia perpetua, Camellia flavida and Camellia tunghinensis belong to the plants of Theaceae Camellia, Sect. Chrysantha Chang, which are the national second-class key protected wild plants. These three species have a narrow distribution range, and the wild resources are on the verge of extinction. Exploring their adaptability to different light environments and searching for suitable growth light intensity can provide theoretical basis for artificial breeding, population recovery and ex-situ protection of these three yellow Camellia species, and also provide partial explanation for the habitat differences of their wild populations. Method: This study used 3-year-old cuttings of the three yellow Camellia species as experimental materials and used artificial shading methods to study the effects of different light intensities (8%, 20%, 45%, 100%) on their photosynthetic physiological characteristics and biomass. Result: (1) The three yellow Camellia species had higher maximum net photosynthetic rate (Pmax), apparent quantum efficiency (AQY), maximum fluorescence (Fm), maximum photochemical efficiency (Fv/Fm), actual photochemical efficiency (ΦPSII) and photosynthetic electron transfer rate (ETR) under low light conditions, indicating that they had better adaptability to low light conditions. (2) The Pmax of C. perpetua remained at a high level under 45% light intensity, and the light saturation point (LSP) showed an increasing trend with the increase of light intensity. However, the Pmax and LSP of C. flavida and C. tunghinensis showed an initial increase and then a decrease with the increase of light intensity, and both reached their maximum values at 20% light intensity. (3) With the increase of light intensity, the contents of total chlorophyll (Chl), chlorophyll a (Chla), Chlorophyll b (Chlb), and carotenoid (Car) in the three yellow Camellia species leaves decreased, Cha/Chb values first decreased and then increased, and Car/Chl values increased. (4) With the increase of light intensity, the root, stem, leaf biomass and total biomass of the three yellow Camellia species increased first and then decreased, the total biomass of the C. perpetua was the highest at 45% light intensity, while the C. flavida and C. tunghinensis were the highest at 20% light intensity. Conclusion: C. perpetua, is more tolerant to strong light, followed by C. flavida, and C. tunghinensis is the weakest. C. perpetua prefers a medium light environment (45% light intensity), while C. flavida and C. tunghinensis prefer a medium to low light environment (20% light intensity). The photosynthetic characteristics of the three yellow are consistent with the distribution of their wild populations in the light environment.