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叶片作为重要的光合器官,是植物光合产物形成的主要场所。叶片干物质量与其叶面积之比定义为比叶质量(Leaf mass per area,LMA),可以理解为叶片水平上光的截留成本[1]。比叶质量是植物叶片关键叶性状之一,是植物生长的重要特征,也是植物生态学、农业和林业上广泛应用的,综合反应植物利用资源的能力以及适应环境的生长策略的重要指标[2-4]。比叶质量在植物生长策略中发挥核心作用,具有低比叶质量的物种倾向于快速的资源获取、快速代谢和增长,高比叶质量物种倾向于较强的资源节约、保护能力和持久性。国内外大量关于比叶质量(LMA)的文献数据分析表明,比叶质量在物种间的变化超过100倍[5]。
植物比叶质量是影响各种生态系统过程的重要因素[5],但不同植物功能群比叶质量随环境梯度可塑性变化的生理调节机制尚不清楚。Poorter等在室内控制条件下通过实验构建比叶质量随环境因子的响应曲线,结果显示,比叶质量随光照、温度和淹水变化而存在很大变化,随CO2浓度、养分及其水分胁迫变化比较适度[5]。Wright等基于全球175个样点2 548种植物的叶性分析表明,比叶质量随降雨量的减少和光照辐射的增加而增大[6]。薛立等研究发现6种阔叶幼苗叶片的比叶质量随幼苗种类和季节而变化,幼苗比叶质量与降雨量、平均气温和光照时间存在二项式关系[2]。
毛竹(Phyllostachys edulis (Carrière) J.Houz.)具有生长快、成材早、产量高、用途广、收益大等优点,是我国南方的重要森林资源。当今全球森林面积急剧下降,竹林面积却以3%的速度递增[7],这意味着竹林是一个不断增大的碳汇。然而,全球气候变化背景下,极端天气气候事件发生频度和强度越来越大,对生态系统结构和功能造成前所未有的威胁。2013年夏季,我国南方出现广泛的、持续时间较长的高温干旱,毛竹林生态系统也遭受严重破坏。水分作为植物生长的重要条件,与毛竹生产力有着密切联系,因此干旱对毛竹林生产力具有重要潜在影响。毛竹研究涉及内容较丰富[8-11],但作为重要生长策略指标,毛竹比叶质量随生长季节、冠层高度、年龄的动态变化及其对干旱适应性特征方面的研究较少[11]。因此,本研究结合毛竹野外人工截雨模拟干旱试验,针对毛竹比叶质量时空动态变化及其对模拟干旱响应进行系统研究,通过阐明不同生长季节、不同冠层部位叶片和不同年龄个体的比叶质量时空动态格局,间接揭示叶片比叶质量在毛竹适应光、水环境的调控策略,旨在探索毛竹季节性资源利用能力的快速判断指标,为全球气候背景下毛竹人工林可持续高效经营提供理论依据。
毛竹比叶质量时空变化及对截雨干旱的响应
Seasonal and Canopy Variation of Leaf Mass Per Area for Phyllostachys edulis Leaves and its Response to Drought Stress
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摘要:
目的 定量分析毛竹叶片比叶质量随生长季节、冠层部位和竹龄的变化及其对截雨干旱的响应,为全球气候变化下毛竹人工林可持续高效经营提供理论依据。 方法 以毛竹为研究对象,通过人工截雨干旱试验,对毛竹叶片比叶质量时空特性进行测定分析。 结果 (1)截雨干旱与自然生长下,毛竹叶片比叶质量存在显著季节差异和年龄差异;不同生长季节,毛竹叶片比叶质量均随竹龄增加而增加;各龄竹比叶质量随生长季节的变化趋势均为春季>冬季>秋季>夏季。(2)截雨干旱与自然生长下,各龄竹比叶质量冠层差异不显著;自然生长下,比叶质量随冠层高度的垂直变化在不同生长季节均为冠层上部>冠层中部>冠层下部;截雨干旱下,比叶质量随冠层高度的变化因生长季节变化而不同。(3)截雨干旱下,各龄竹不同季节的比叶质量均高于自然生长下的比叶质量。干旱缓解了各冠层比叶质量的季节差异。截雨干旱与自然生长间比叶质量差异显著性受竹龄影响。(4)不同处理下各季节毛竹叶片比叶质量与土壤含水量、竹龄呈线性正相关。 结论 毛竹属于低比叶质量物种,生长季节显著影响其比叶质量变化;与光照相比,土壤水分条件对毛竹比叶质量产生重要影响。 Abstract:Objective To quantitatively analyze the seasonal change of leaf mass per area (LMA) along canopy height for different aged moso bamboo (Phyllostachys edulis) in natural and drought stress growth environment, and to clarify the response characteristics of LMA to the throughfall exclusion for drought stress, aiming at providing references for sustainable and efficient management of Ph. edulis plantations under the global climate background. Method The spatial and temporal dynamic change of LMA is detected for moso bamboo under two different treatments with rain shelter or not. Result (1) Regardless of throughfall exclusion or not, the LMA increased with the age of bamboo during different growing seasons, and the seasonal change trend from maximum to minimum was spring, winter, autumn and then summer in turn. There were significant differences of LMA among different seasons and treatments for the same age of bamboo (P < 0.05), regardless of throughfall exclusion or not. (2) Regardless of throughfall exclusion or not, the differences of LMA were not significant among canopy for various ages of bamboo, while it was significant among seasons within the same canopy. In natural growth condition, the LMA of each season increased along with the canopy height and its vertical change showed the trend of the upper canopy > middle canopy > lower canopy successively, and the value of each canopy decreased at first and then increased as the growing season. There was significant difference among different seasons (P < 0.01) for LMA of different ages of bamboo, while there was no significant difference among different canopy layers under throughfall exclusion. (3) Under the drought stress, the annual average value and each individual value of the LMA were all higher than the control in every season. The drought stress relieved seasonal difference of LMA in various canopy. The seasonal change of the LMA within the same canopy was also affected by age of bamboo. (4) With or without drought stress, there was linear positive correlation between the LMA and soil water content in each season, but the correlation under drought stress was lower than that of the control. The positive correlation between LMA and ages of bamboo under drought stress was higher than that of the control. Conclusion It is concluded that moso bamboo belongs to the species with lower LMA, and the growth season has significant effect on the change of LMA. Compared with the light, the soil moisture condition has more important influence on the LMA of the moso bamboo. -
Key words:
- Phyllostachys edulis
- / drought stress
- / leaf mass per area
- / season
- / age
- / canopy height
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[1] Gutschick V P, Wiegel F W. Optimizing the canopy photosynthetic rate by patterns of investment in specific leaf mass[J]. The American Naturalist, 1988, 132(1):67-86. doi: 10.1086/284838 [2] 薛立, 张柔, 奚如春, 等.华南地区6种阔叶幼苗叶片形态特征的季节变化[J].生态学报, 2012, 32(1):123-134 [3] Lambers H, Poorter H. Inherent variation in growth rate between higher plants:a search for physiological causes and ecological consequences[J]. Advances in Ecological Research, 1992, 22(1):187-261. [4] Westoby M, Falster D S, Moles A T, et al. Plant ecological strategies:some leading dimensions of variation between species[J]. Annual Review of Ecology & Systematics, 2002, 33(1):125-159. [5] Poorter H, Niinemets U, Poorter L, et al. Causes and consequences of variation in leaf mass per area (LMA):a meta-analysis[J]. New Phytologist, 2009, 182(3):565-588. doi: 10.1111/j.1469-8137.2009.02830.x [6] Wright I J, Reich P B, Westoby M, et al. The worldwide leaf economics spectrum[J]. Nature, 2004, 428(8985):821-827. [7] 唐晓鹿, 范少辉, 漆良华, 等.采伐对幕布山区毛竹林土壤呼吸的影响[J].林业科学研究, 2013, 26(1):52-57 doi: 10.3969/j.issn.1001-1498.2013.01.009 [8] Wen G S, Zhang L Y, Zhang R M, et al. Temporal and spatial dynamics of carbon fixation by moso bamboo(Phyllostachys pubescens) in subtropical China[J]. Botanical Review, 2011, 77(3):271-277. doi: 10.1007/s12229-011-9068-x [9] 应叶青, 郭璟, 魏建芬, 等.干旱胁迫对毛竹幼苗生理特性的影响[J].生态学杂志, 2011, 30(2):262-266. [10] 袁佳丽, 温国胜, 张明如, 等.毛竹快速生长期的水势变化特征[J].浙江农林大学学报, 2015, 32(5):722-728. [11] 曹永慧, 周本智, 王小明, 等.冠层高度对毛竹叶片光合生理特性的影响[J].西北植物学报, 2016, 36(11):2256-2266 doi: 10.7606/j.issn.1000-4025.2016.11.2256 [12] 郑淑霞, 上官周平.不同功能型植物光合特性及其与叶氮含量、比叶质量的关系[J].生态学报, 2007, 27(1):171-181 doi: 10.3321/j.issn:1000-0933.2007.01.020 [13] Wright I J, Wearoby M. Cross-species relationship between seedling relative growth rate, nitrogen productivity and root vs. leaf function in 28 Australian woody species[J]. Functional Ecology, 2000, 14(1):97-107. doi: 10.1046/j.1365-2435.2000.00393.x [14] Isagi Y. Ecological study of bamboo communities:a resource-based approach[J]. Bull Fac Int Arts Sci Hiroshima Univ, 1995, 4(21), 235-238(in Japanese). [15] 董伊晨, 刘艳红.红松不同苗龄幼苗叶性状对温度和光照变化的响应[J].生态学报, 2017, 37(17):5662-5672 [16] Poorter L. Leaf traits show different relationships with shade tolerance in moist versus dry tropical forests[J]. New Phytologist, 2009, 181(4):890-900. doi: 10.1111/j.1469-8137.2008.02715.x [17] 冯玉龙, 曹坤芳, 冯志立, 等.四种热带雨林树种幼苗比叶质量, 光合特性和暗呼吸对生长光环境的适应[J].生态学报, 2002, 22(6):901-910 doi: 10.3321/j.issn:1000-0933.2002.06.015 [18] 何春霞, 李吉跃, 张燕香, 等.5种绿化树种叶片比叶重、光合色素含量和δ13C的开度与方位差异[J].植物生态学报, 2010, 34(2):134-143 doi: 10.3773/j.issn.1005-264x.2010.02.004 [19] 王子奇, 查天山, 贾昕, 等.油蒿光合参数季节动态及其与叶氮含量和比叶面积的关系[J].生态学杂志, 2017, 36(4):916-924. [20] Shipley B. Structured interspecific determinants of specific leaf area in 34 species of herbaceous angiosperms[J]. Functional Ecology, 1995, 9(2):312-319. doi: 10.2307/2390579 [21] Koch G W, Sillett S C, Jennings G M, et al. The limits to tree height[J]. Nature, 2004, 428(6985):851-854. doi: 10.1038/nature02417 [22] Cao K F. Leaf anatomy and chlorophyll content of 12 woody species in contrasting light conditions in a Bornean heath forest[J]. Canadian Journal of Botany, 2000, 78(10):1245-1253. doi: 10.1139/b00-096 [23] Sterck F J, Poorter L, Schieving F. Leaf traits determine the growth-survival trade-off across rain forest tree species[J]. American Naturalist, 2006, 167(5):758-765. doi: 10.1086/503056 [24] Puglielli G, Crescente M F, Frattaroli A R, et al. Leaf mass per area (LMA) as a possible predictor of adaptive strategies in two species of Sesleria (Poaceae):analysis of morphological, anatomical and physiological leaf traits[J]. Annales Botanici Fennici, 2015, 52(1-2):135-143. doi: 10.5735/085.052.0201