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林业科学 ›› 2022, Vol. 58 ›› Issue (5): 53-64.doi: 10.11707/j.1001-7488.20220506

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光强对金丝李幼苗生长及光合特性的影响

张俊杰1,刘青2,韦霄3,*,张建军1,郭庭鸿1   

  1. 1. 重庆交通大学建筑与城市规划学院 重庆 400074
    2. 南昌师范学院 美术学院 南昌 330032
    3. 广西壮族自治区中国科学院广西植物研究所 桂林 541006
  • 收稿日期:2020-12-30 出版日期:2022-05-25 发布日期:2022-08-19
  • 通讯作者: 韦霄
  • 基金资助:
    广西自然科学基金项目(2015GXNSFDA13915);广西科技基地和人才专项(桂科AD17129022);重庆交通大学博士科研启动基金(2020019089)

Influence of Light Intensity on Growth and Photosynthetic Characteristics of Garcinia paucinervis seedlings

Junjie Zhang1,Qing Liu2,Xiao Wei3,*,Jianjun Zhang1,Tinghong Guo1   

  1. 1. College of Architecture and Urban Planning, Chongqing Jiaotong University Chongqing 400074
    2. College of Fine Arts, Nanchang Normal University Nanchang 330032
    3. Guangxi Institute of Botany, Guangxi Zhuangzu Autonomous Region and the Chinese Academy of Sciences Guilin 541006
  • Received:2020-12-30 Online:2022-05-25 Published:2022-08-19
  • Contact: Xiao Wei

摘要:

目的: 研究岩溶山地的珍稀濒危树种金丝李苗对光照的需求及适应规律, 为其引种、迁地保护、种群复壮、规模化栽培和用于岩溶山体生态恢复提供依据。方法: 将3年生金丝李幼苗进行为期2年相对光强10%、25%、50%和100%处理(分别记为RI10%、RI25%、RI50%和RI100%), 对其生长和叶片特征、生物量分配、光合特性、叶片光合色素含量及叶绿素荧光参数进行比较, 分析其对不同光环境的适应机制。结果: 1) 金丝李幼苗在4种光强下均能生长, 2年后RI25%和RI50%的地径、株高和冠幅显著大于RI10%和RI100%处理。2) RI25%的单叶面积和叶片厚度显著大于其他处理, 生物量、比叶面积和叶面积比随光强增加呈先增大后减小的趋势, RI100%的根生物量比与根冠比最大, 显著大于RI10%处理。3) 第1年, 幼苗的最大净光合速率(Pmax)和表观量子效率(AQY)的排序为RI50%>RI25%>RI100%>RI10%, 光饱和点(LSP)、光补偿点(LCP)和暗呼吸速率(Rd)均随着光强的增加而增大; 第2年RI50%、RI25%和RI10%的Pmax和AQY值差异不显著, 但均大于RI100%处理, 除RI100%的LSP相比第1年降低外, RI10%、RI25%和RI50%处理的LSP均相较第1年增高; 全天净光合速率(Pn)最高值排序为RI50%≈RI25%>RI10%>RI100%; 在全天大部分时间里, RI100%的Pn、气孔限制值(Ls)、水分利用效率(WUE)和光能利用效率(LUE)均低于RI10%、RI25%和RI50%处理, 胞间CO2浓度(Ci)则高于其他光强处理。4) 幼苗叶片的叶绿素a、叶绿素b及类胡萝卜素含量均随着光强的增加显著降低; RI100%的类胡萝卜素与叶绿素的比值显著大于其他3种光强处理。5) 第2年, 可变荧光(Fv)、潜在光化学效率(Fv/Fo)、最大光化学效率(Fv/Fm)、表观电子传递速率(ETR)和光化学淬灭系数(qP)均以RI25%最高, 与第1年相比变化显著, 但RI100%的上述参数显著低于其他3种光强处理。结论: 金丝李幼苗在形态及光合生理上具有对光环境的调节和适应能力。全光环境下幼苗受胁迫导致生长缓慢; 在重度遮荫下虽生长较慢但各项光合生理指标均正常, 表明其对弱光有一定的适应能力; 而在相对光照为25%~50%的环境下生长良好, 其幼苗叶片可通过增加对光能的吸收能力及提高PSⅡ反应中心的光化学效率来充分利用光能。人工培育幼苗时需适度遮荫。森林过度采伐造成的强光胁迫可能是金丝李致濒的环境因子之一。

关键词: 光照强度, 适应性, 光响应曲线, 叶绿素荧光, 珍稀濒危, 日变化

Abstract:

Objective: In this paper, the light requirement and adaptation rules of the seedlings of Garcinia paucinervis, a rare and endangered plant, in karst mountains were studied, in order to provide a theoretical basis for its introduction, ex situ conservation, population rejuvenation, large-scale cultivation and ecological restoration of karst mountains. Method: The 3-year-old G. paucinervis seedlings were treated with different relative natural light intensities of 10%, 25%, 50% and 100% (marked as RI10%, RI25%, RI50% and RI100%, respectively) for two years. The dynamic changes of growth and leaf morphology features, biomass allocation, photosynthetic characteristics, photosynthetic pigment content in leaves and chlorophyll fluorescence parameters were compared, and the adaptation mechanisms of seedlings to different light environments were analyzed. Result: 1) After two years of light treatment, the ground diameter, plant height and crown width of RI25% and RI50% treatments were significantly greater than those of RI10% and RI100% treatments. 2) The individual leaf area and leaf thickness of RI25% treatment were the greatest in the 4 treatments. The biomass, specific leaf area and leaf area ratio increased first and then decreased with the increase of light intensity. The root mass ratio and root to shoot ratio of RI100% treatment were the greatest, and significantly higher than that of RI10% treatment. 3) In the first year, the order of the maximum net photosynthetic rate (Pmax) and apparent quantum yield (AQY) were RI50% > RI25% > RI100% > RI10%. The light saturation point (LSP), light compensation point (LCP) and dark respiration rate (Rd) increased with the increase of light intensity. There were no significant differences in Pmax and AQY values of RI50%, RI25% and RI10% in the second year, which however were higher than those of RI100% treatment. Except that the LSP of RI100% treatment was lower than that inthe first year, the LSP of the three shading treatments were higher than that in the first year. The highest value of net photosynthetic rate (Pn) in thewhole day was in the order of RI50% ≈ RI25% > RI10% > RI100%. In the most time of the whole day, Pn, stomatal limitation(Ls), water use efficiency(WUE) and light use efficiency(LUE) of RI100% treatment were lower than those of the three shading treatments, and the internal cellular CO2 concentration(Ci) of RI100% treatment was higher than those of the three shading treatments. 4) With the increase of light intensity, the contents of chlorophyll a, chlorophyll b and carotenoids in seedling leaves decreased significantly.The ratio of carotenoids to chlorophyll in RI100% treatment was significantly higher than that in the three shading treatments. 5) In the second year, variable fluorescence(Fv), photochemical efficiency of PSII(Fv/Fo)and maximum photochemical efficiency(Fv/Fm), electron transfer rate(ETR) and photochemical quenching coefficient(qP) were the highest in RI25% treatment, which changed significantly compared with the first year, while those parameters of RI100% treatment was significantly lower than the three shading treatments. Conclusion: G. paucinervis seedlings have the ability to adjust and adapt to the light environment in, the morphology and photosynthetic physiology. Seedlings grow slowly under stress in full light environment; Although the seedlings grow slowly under heavy shading, all photosynthetic physiological indexes are normal, indicating that they have adaptability to weak light; However, the seedlings grow well under 25%~50% relative light intensity, and their seedling leaves can make full use of light energy by increasing the absorption capacity of light energy and the photochemical efficiency of PSⅡ. G. paucinervis seedlings cultivation needs moderate shade. It is speculated that the strong light stress caused by deforestation is one of the environmental factors for G. paucinervis endangerment.

Key words: light intensity, adaptability, Pn-PFD response curve, chlorophyll fluorescence, rare and endangered, diurnal variation

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