| 引用本文: | 覃兰丽, 庞玉堃, 张天浩, 安倚东, 蒋国凤.三种苏铁植物呈现出迥异的水力安全边界[J].广西植物,2022,42(9):1602-1611.[点击复制] |
| QIN Lanli, PANG Yukun, ZHANG Tianhao, AN Yidong, JIANG Guofeng.Contrasting hydraulic safety margins of three cycads[J].Guihaia,2022,42(9):1602-1611.[点击复制] |
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| 三种苏铁植物呈现出迥异的水力安全边界 |
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覃兰丽1,2, 庞玉堃1,2, 张天浩1,2, 安倚东1,2, 蒋国凤1,2*
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1. 广西大学 林学院, 广西森林生态与保育重点实验室, 南宁 530004;2. 广西大学
亚热带农业生物资源保护与利用国家重点实验室, 南宁 530004
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| 摘要: |
| 为探究苏铁植物的水力安全边界(hydraulic safety margins, HSM),该试验选用经典的自然干燥法和最新发表的抽气法测定三种同质园苏铁植物抗旱性(即叶轴木质部脆弱性曲线),获得抗旱指标P50和P88(导水率丧失或气体抽取量分别为50%和88%时的木质部水势),与叶片正午水势计算HSM,结合管胞性状分析。结果表明:(1)苏铁(Cycas revoluta)、越南篦齿苏铁(C. elongata)、摩瑞大泽米苏铁(Macrozamia moorei)的管胞长度分别为(4 413±378)、(5 146±730)、(6 954±862)μm,苏铁、越南篦齿苏铁与摩瑞大泽米苏铁差异显著(P<0.05)。(2)两种方法测定的脆弱性曲线都呈典型的“S”型,苏铁、越南篦齿苏铁、摩瑞大泽米苏铁的P50H(导水率丧失50%时的木质部水势)和P50P(气体抽取量为50%时的木质部水势)分别为-2.5、(-2.4±0.5)MPa,-2.3、(-3.6±0.7)MPa,-1.5、(-1.8±0.2)MPa,在已发表的裸子植物数值范围内。P50和P88具有显著一致性(除了越南篦齿苏铁的P50P 比P50H更低,表示更强抗旱性),与已发表的其他木质部管胞物种通过水力学法和抽气法获得的P50和P88比较分析,具有显著相关性(R2=0.72, P=0.008 1; R2=0.87, P=0.000 7)。(3)自然干燥法和抽气法计算的HSMs具有相同的趋势,摩瑞大泽米苏铁为负值,而苏铁和越南篦齿苏铁为正值。综上所述,三种苏铁植物的抗旱性均在已发表的裸子植物范围内,两种方法都适于测定木质部管胞结构的苏铁类植物脆弱性曲线,苏铁、越南篦齿苏铁与摩瑞大泽米苏铁具有不同的水力安全边界。利用脆弱性曲线和正午水势探讨苏铁植物的水力安全边界,为苏铁植物的水分监测、管理和保育提供依据。 |
| 关键词: 气穴化, 水力安全边界, 苏铁植物类群, 抽气法, 自然干燥法, 导水率, 抗旱性 |
| DOI：10.11931/guihaia.gxzw202108062 |
| 分类号:Q945 |
| 文章编号:1000-3142(2022)09-1602-10 |
| 基金项目:国家自然科学基金(31860195); 广西自然科学基金(2022GXNSFDA035059)[Supported by National Natural Science Foundation of China(31860195); Guangxi Natural Science Foundation(2022GXNSFDA035059)] 。 |
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| Contrasting hydraulic safety margins of three cycads |
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QIN Lanli1,2, PANG Yukun1,2, ZHANG Tianhao1,2, AN Yidong1,2, JIANG Guofeng1,2*
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1. Guangxi Key Laboratory of Forest Ecology and Conservation, Forestry College of Guangxi University, Nanning 530004, China;2. State
Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning 530004, China
1. Guangxi Key Laboratory of Forest Ecology and Conservation, Forestry College of Guangxi University, Nanning 530004, China; 2. State
Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning 530004, China
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| Abstract: |
| To investigate hydraulic safety margins(HSM)of cycads, drought resistances(rachis xylem vulnerability curve)of three common garden cycad species were measured by the classic bench dehydration and the newly published pneumatic methods. Drought resistance traits P50 and P88(xylem water potential at 50% and 88% loss of hydraulic conductivity or air discharged respectively)were obtained from the curves, with midday leaf water potential, HSMs were then calculated, combined with the analysis of tracheid traits. The results were follows:(1)Cycas revoluta and C. elongata had similar values, while Macrozamia moorei had significantly longer tracheid length(P<0.05), which were(4 413±378),(5 146±730),(6 954±862)μm, respectively.(2)The vulnerability curves obtained by the two methods were typical sigmoidal “S” type, P50H(xylem water potential at 50% loss of hydraulic conductivity)and P50P(xylem water potential at 50% air discharged)of Cycas revoluta, C. elongata and Macrozamia moorei were -2.5,(-2.4±0.5)MPa; -2.3,(-3.6±0.7)MPa; -1.5,(-1.8±0.2)MPa, respectively. Values of P50 for the three cycads species were in the range of published values of gymnosperms. Further, P50 and P88 showed significant consistency with the two methods(except P50P had greater resistance than P50H in Cycas elongata), and also showed significant correlations with published data for other tracheid species(R2=0.72, P=0.008 1; R2=0.87, P=0.000 7).(3)HSM obtained by bench dehydration and pneumatic methods showed consistent trends, Macrozamia moorei had a negative HSM, both Cycas revoluta and C. elongata had positive HSMs. For conclusion, xylem drought resistant of the three cycads were in the range of to the reported data of gymnosperms, the pneumatic and bench dehydration methods were suitable for determining the vulnerability curves of cycads. Moreover, C. revoluta, C. elongata and Macrozamia moorei had different hydraulic safety margins. Determining the HSMs of cycads with vulnerability curves and midday water potentials will provide the basic hydraulic traits in these plants which will be useful in water monitoring, management, and conservation of cycads. |
| Key words: cavitation, hydraulic safety margins, cycads, pneumatic method, bench dehydration method, hydraulic conductivity, drought resistance |
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