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  chlorophyll  photosynthetic characteristics  biomass

摘要:

四季花金花茶(Camellia perpetua)、淡黄金花茶(C.flavida)和东兴金花茶(C.tunghinensis)隶属山茶科(Theaceae)山茶属(Camellia)金花茶组(Camellia Sect.Chrysantha)，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，探索其对不同光照环境的适应性，寻找适宜其生长的光照强度，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。本研究以上述3种金花茶3年生扦插苗为试验材料，采用人工遮阴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。结果表明：(1)3种金花茶在低光照环境(8%和20%光照强度)下有较大的最大净光合速率(P_max)、表观量子效率(AQY)、最大荧光(F_m)、最大光化学效率(F_v/F_m)、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P_max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P_max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(Chl a)、叶绿素b(Chl b)和类胡萝卜素(Car)含量降低，Car/Chl值升高，Chl a/Chl b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先升高后降低，其中四季花金花茶在45%光照强度下最高，而淡黄金花茶和东兴金花茶则在20%光照强度下最高。综上可知，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,C.flavida and C.tunghinensis belong to Theaceae，Camellia and Camellia Sect.Chrysantha.They are the second-class national key protected wild plants.The distribution range of these three species is narrow,and the wild resources are on the verge of extinction.Exploring their adaptability to different light environments and finding the light intensity suitable for their growth can provide a theoretical basis for the artificial breeding,population restoration and ex-situ protection of these three yellow Camellia species,and can also provide a partial explanation for the reasons for the habitat differences of their wild populations.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.The results showed that:(1) The three yellow Camellia species had higher maximum net photosynthetic rate (P_max),Apparent Quantum Yield (AQY),maximum fluorescence (F_m),maximum photochemical efficiency (F_v/F_m),actual photochemical efficiency (ΦPSⅡ) and photosynthetic Electron Transfer Rate (ETR) under low light conditions (8% and 20% light intensity),indicating that they had better adaptability to low light environment.(2) The P_max 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 P_max and LSP of C.flavida and C.tunghinensis increased first and then decreased with the increase of light intensity,and both reached the maximum at 20% light intensity.(3) With the increase of light intensity,the contents of total chlorophyll (Chl),chlorophyll a (Chl a),Chlorophyll b (Chl b),and carotenoid (Car) in the three yellow Camellia species leaves decreased,Car/Chl values increased,and Chl a/Chl b values first decreased and then 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.Among them,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.In summary,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 Camellia species are consistent with the characteristics of the light environment of the wild population.