Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： Exploring the response of leaf and root morphological characteristics of desert plants to drought stress is helpful in understanding and predicting their growth regulation strategies under the climate change scenario. The seedlings of the typical desert plant Caroxylon passerinum were treated with slow and rapid drought, and the morphological indices of leaves and roots were measured. The morphological characteristics of leaves and roots of C. passerinum seedlings under drought stress were analyzed using slow and fast drought treatments. The results showed that: (1) with an extension in slow drought stress treatment time, thick- root diameter, fine- root specific length, and specific root area decreased; the leaf tissue density under rapid drought treatment increased; after slow drought treatment, the thick-root tissue density increased, while it increased at first and then decreased post- rapid drought treatment. (2) At the end of the growth period of 54 days, the thick- root diameter reduced markedly under the two treatments; the succulent degree and water content were significantly lower under rapid drought than those of the control and slow drought treatments, respectively. The thick- root tissue density of C. passerinum seedlings increased significantly after 37 days of stress, which was higher post- slow than fast drought. (3) The first four axes of principal components were mainly affected by coarse-root specific root length, thick-root tissue density, fine-root specific root length, and specific leaf area. Correlation analysis revealed that 29 pairs of characters were interrelated. In summary, the leaves, thick roots, and fine roots of C. passerinum showed varying adaptation strategies especially by reducing the diameter of thick roots under the two types of drought treatment. Under rapid drought, C. passerinum adapted to soil water deficit by enhancing the leaf tissue density and reducing fine-root specific root length and specific root area. Thus, C. passerinum seedlings adapt to drought through a coordination or tradeoff within and between leaf and root traits.
Subjects: Geosciences >> Geography submitted time 2021-04-23 Cooperative journals: 《干旱区研究》
Abstract：植物对干旱的适应能力不仅包括干旱胁迫期间的抗旱能力，也包括复水之后的恢复能力，因此，开展干旱复水条件下植物幼苗生长及根系形态特征变化规律的研究，对揭示植物抗旱生理机制具有重要意义。通过盆栽控水进行干旱胁迫和复水处理，测定了干旱-复水条件下红砂幼苗基径、株高、生物量以及根系形态指标，分析了其生长、生物量分配及根系形态特征对干旱-复水的响应。结果表明：（1）与适宜水分相比，干旱胁迫下红砂幼苗基径和株高相对增量以及地上、地下和总生物量显著减小（P<0.01），各干旱胁迫下红砂幼苗基径相对增量随时间增加呈现减小的变化趋势；复水后中度和重度胁迫处理下红砂幼苗基径和株高相对增量较大，表明红砂幼苗在较严重的干旱胁迫下复水时，其地上部分恢复生长更快；（2）与适宜水分相比，干旱胁迫下红砂幼苗比根长显著增加（P<0.01），表明红砂幼苗可通过根系伸长生长以适应干旱胁迫；复水后重度干旱胁迫处理下红砂幼苗总根长、根表面积和总根体积减小，而红砂幼苗根系直径显著增加（P<0.01），表明红砂幼苗在重度胁迫处理下根系恢复力减弱。综上所述，干旱胁迫期间红砂幼苗通过加快基径和根系的生长储存更多物质来应对胁迫环境，从而表现出较强的抵抗力；复水后红砂幼苗通过加快地上部分生长和根系直径与比根长的增大来恢复生长，有助于提高其较强的恢复能力。
Subjects: Geosciences >> Geography submitted time 2021-04-23 Cooperative journals: 《干旱区研究》
Abstract：以红砂幼苗为研究对象，测定了不同降水［降水减少30%（W-）、自然降水（W）和降水增多30%（W+）］和氮添加［N0（0 g·m-2·a-1）、N1（4.6 g·m-2·a-1）、N2（9.2 g·m-2·a-1）、N3（13.8 g·m-2·a-1）］条件下红砂幼苗叶片的脯氨酸（Pro）、叶绿素（Chl）、超氧化物歧化酶（SOD）、过氧化物酶（POD）和可溶性蛋白（SP）含量。结果表明：（1）在自然降水量（W）和降水量增加30%（W+）条件下，随施氮量的增加，红砂脯氨酸和叶绿素含量呈增加趋势，说明水分条件适宜时，水氮会发挥耦合效应促进脯氨酸和叶绿素的积累。（2）在无氮添加（N0）和低氮（N1）水平下，自然降水量（W）条件下的POD活性分别显著小于降水量减少30%（W-）条件下的值，中氮（N2）、高氮（N3）水平下则明显相反。说明在低氮水平下，降水量增加抑制POD活性的增加，而中氮和高氮添加极大地减缓这种抑制作用，促进POD活性的增强，表现了氮水间的补偿效应。（3）在自然降水量（W）条件下，随氮添加量的增加，可溶性蛋白含量先增大后减小，而降水量减少30%（W-）条件下，氮添加对可溶性蛋白含量影响不显著。说明在正常水分条件下，适量的氮素添加会促进植物体内蛋白的转化，但当施氮量达到一定临界值时，氮素含量的持续增加将会抑制可溶性蛋白的产生，而水分亏缺时施氮对可溶性蛋白的转化无显著影响。
Subjects: Geosciences >> Geography submitted time 2020-12-17 Cooperative journals: 《干旱区研究》
Abstract：水分和氮素是荒漠生态系统植物生长的主要限制因子，了解降水变化和氮沉降加剧如何影响典型荒漠植物根系形态特征，有助于揭示全球气候变化背景下的典型荒漠植物响应和适应机制，为有效进行荒漠植物恢复建设及管理提供理论依据。采用盆栽试验，研究了红砂（Reaumuria soongorica）幼苗根系形态特征对不同氮添加量（0g·m-2·a-1）、4.6 g·m-2·a-1、9.2 g·m-2·a-1和13.8 g·m-2·a-1和降水处理［（70%（W-）、100%（自然降水W）、130%（W+）］的响应。结果表明：（1）降水对红砂幼苗总根长、总表面积、总根体积、根系生物量、比根长和比表面积均有极显著影响（P0.05）。同一氮水平下，随降水量的增加红砂总根长、总表面积、总根体积、根生物量、比根长、比表面积均呈现增大的趋势，且在降水量130%处理下（W+）各相关指标达到最大值；在降水量70%（W-）和降水量不变（W）的条件下，红砂根系各形态指标随着氮添加量的增加呈现出先增大后减小的趋势，而在降水量130%条件下（W+），各指标随着氮含量的增加大致呈先减小后增大的趋势，且各个指标均在增水、高氮水平时最大。可见，红砂根系生长主要取决于降水，且红砂根系生长存在明显的水氮耦合效应，在高水、高氮条件下，红砂根系生长促进效应最明显。在我国西北干旱和半干旱区，可以在雨季降水量大时通过施入氮肥（N3）来促进红砂根系快速生长、下扎；在干旱少雨时，通过施入适量的氮肥（N1）来促进红砂根系的生长，缓解干旱对红砂根系的限制作用。
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