| 白枪杆生长特性及光合特性对不同土壤水分的响应 |
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| 引用本文： | 黄俊威,孙永磊,周金星,刘玉国,万龙.白枪杆生长特性及光合特性对不同土壤水分的响应[J].浙江农林大学学报,2019,36(6):1254-1260. |
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| 作者姓名： | 黄俊威 孙永磊 周金星 刘玉国 万龙 |
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| 作者单位： | 1.北京林业大学 水土保持学院 云南建水荒漠生态系统国家定位观测研究站, 北京 1000832.北京林业大学 水土保持国家林业局重点实验室, 北京 1000833.中国林业科学研究院 荒漠化研究所, 北京 100091 |
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| 基金项目： | "十三五"国家重点研发计划项目2016YFC0502502国家自然科学基金资助项目31700640 |
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| 摘 要： | 中国西南喀斯特地区石漠化现象日益严重。白枪杆Fraxinus malacophylla作为该地区的乡土物种，被广泛应用于当地的植被恢复工程中，研究白枪杆对不同土壤水分的响应规律，明确白枪杆对西南喀斯特区土壤水分时空分布不均的适应方式，有助于推动西南石漠化地区植被恢复进程。以1年生白枪杆实生苗为材料，通过盆栽控制试验，测定土壤含水量为40%，34%，28%，22%和16%条件下白枪杆生物量、净光合速率、气孔导度、胞间二氧化碳摩尔分数、蒸腾速率等参数，探究白枪杆对不同土壤水分的响应情况。结果表明:①白枪杆在5种土壤水分条件下均能存活，其生长的最适土壤含水量为28%，总生物量为17.16 g。土壤含水量过多或不足都会显著降低白枪杆的净光合速率和生物量积累。②土壤含水量不足28%时，白枪杆将生物量优先分配到根系生长以适应干旱环境，当土壤含水量低至16%时，根生物量比例超过50%。在一定的土壤水分范围内，白枪杆通过关闭一部分气孔保证植物光合作用的正常进行，表现出较强的抗旱能力，但土壤含水量低至16%时，白枪杆受到干旱胁迫影响，总生物量、净光合速率和水分利用效率均显著降低。③土壤含水量高于28%时，白枪杆根系生长受阻，进而导致地上生物量显著降低，净光合速率显著下降。白枪杆的耐涝能力稍逊于其抗旱能力，多雨季节应当注意排水防涝。④除土壤含水量16%处理以外，白枪杆在不同土壤水分条件下的水分利用效率均能保持在2.40 mmol·mol-1以上，能极大适应西南喀斯特地区土壤水分时空分布不均的现状。
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| 关 键 词： | 植物学 白枪杆 土壤含水量 生长特性 光合特性 |
| 收稿时间： | 2018-12-11 |
Growth and photosynthetic characteristic responses of Fraxinus malacophylla to different soil moisture conditions |
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| HUANG Junwei,SUN Yonglei,ZHOU Jinxing,LIU Yuguo,WAN Long.Growth and photosynthetic characteristic responses of Fraxinus malacophylla to different soil moisture conditions[J].Journal of Zhejiang A&F University,2019,36(6):1254-1260. |
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| Authors: | HUANG Junwei SUN Yonglei ZHOU Jinxing LIU Yuguo WAN Long |
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| Institution: | 1.Jianshui Research Station, College of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China2.Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China3.Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China |
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| Abstract: | To promote the process of vegetation restoration due to rocky desertification in southwest China, Fraxinus malacophylla, a native species in southwest China, has been widely used in local vegetation restoration projects. To determine its response to different soil moisture conditions, one-year-old F. malacophylla seedlings were used in a pot experiment to study responses to different soil moisture conditions. The biomass, net photosynthetic rate, stomatal conductance, intercellular carbon dioxide concentration, and transpiration rate were measured for five soil moisture conditions:40%, 34%, 28%, 22%, and 16% split-plot design with treatments of W1, W2, W3, W4, W5 and 10 replications. The growth characteristic of seedings was measured by steel tape and balance while the photosynthetic characteristic was measured by Li-6400. Results showed that (1) F. malacophylla seedlings could survive in the five soil moisture conditions. The optimum soil moisture treatment for seedling growth was 28% with a total seedling biomass of 17.16 g. When water conditions were excessive or inadequate, growth and photosynthesis of F. malacophylla seedlings decreased (P < 0.05). (2) When soil moisture was < 28%, biomass was preferentially allocated to root growth to help in adapting to a drought environment, and when soil moisture was 16%, root biomass was over 50%. With low soil moisture, F. malacophylla improved its drought resistance by closing some stomata to ensure normal photosynthesis. Also, when soil moisture was 16%, drought stress reduced the photosynthetic capacity resulting in a significant decrease in total biomass, net photosynthetic rate, and water use efficiency (P < 0.05). (3) When the soil moisture condition was 34% and 40%, root growth of F. malacophylla was hindered leading to a strong decrease in aboveground biomass and net photosynthetic rate (P < 0.05). (4) Except for the 16% soil moisture treatment, water use efficiency of F. malacophylla with the different soil moisture conditions was>2.40 mmol·mol-1. Thus, F. malacophylla could adapt to the uneven spatial and temporal distribution of soil moisture in the southwest karst region, but drainage and water logging prevention were necessary during the rainy season. |
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