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: Biology >> Ecology submitted time 2023-03-13 Cooperative journals: 《干旱区研究》
Abstract： The understanding of the evolution process of barchan dune and its movement rate is an important prerequisite for wind prevention and sand fixation and ecological construction in Minqin oasis. Based on field measurement and high- resolution remote sensing image analysis, The study discusses the relationship between the morphological parameters of barchan dune and its movement rate in the upwind edge of Minqin oasis. The results show that: (1) The aspect ratio of the dunes remains a constant value of 16 in 16 years. (2) The average annual moving distance of the tall dune is less than 3 m, which is a medium moving speed. The shape of the tall dune is basically unchanged, and the change is obvious only at the baseline, ridge line, and wing Angle of the windward slope. Low dunes move fast, with an average annual distance of more than 10 m, which is an extremely fast-moving speed. (3) The downwind velocity of the dune is inversely proportional to its width, and the proportionality constant is 718.52 m2 ·a-1. In this area, the barchan dune is dominated by fast-moving speed, which is greater than 5 m·a-1, accounting for 52.63%. (4) During the process of sand erosion on the windward slope and deposition on the leeward slope, large dunes maintain stable morphology and move slowly. Small dunes change dramatically and move rapidly, and the dunes tend to shrink in development.
Subjects: Environmental Sciences, Resource Sciences >> Other Disciplines of Environmental Sciences, Resource Sciences submitted time 2021-03-02 Cooperative journals: 《干旱区研究》
Abstract：以临泽县4种生境（沙丘生境、盐渍生境、盐渍-沙丘过渡生境、沼泽生境）芦苇根茎和芦苇根际土壤为研究对象，测定不同生境下芦苇根茎生长发育指标、根际土壤微生物数量及水分、盐分含量，分析了不同生境下根茎生长发育与根际土壤微生物数量、土壤含水量及含盐量的关系。结果表明：（1）对比4种生境下芦苇根茎发育，从盐渍生境，到盐渍-沙丘过渡生境、沙丘生境，再到沼泽生境，根茎节间距呈缩短趋势，而节直径、根茎长度及不定芽数呈增长趋势，根茎含水量和根茎生物量、株高、基径也呈增加趋势。（2）根际土壤微生物数量在4种生境之间差异显著，盐渍生境下芦苇根际土壤真菌数量最多，细菌、放线菌数量最少；沼泽生境芦苇根际土壤真菌数量最少，细菌、放线菌数量最多。（3）相关性分析表明，芦苇根际土壤微生物数量对芦苇根茎数量特征的驱动作用不同。土壤细菌、放线菌数量、B/F值是芦苇根茎长度、根茎节直径、根茎生物量、根茎含水量、株高、基径的主要影响因子，土壤真菌是芦苇根茎节间距的主要影响因子。土壤细菌、真菌、放线菌、B/F是芦苇根茎不定芽数的主要影响因子。土壤细菌、放线菌、B/F值为正向驱动，真菌为负向驱动。
Subjects: Environmental Sciences, Resource Sciences >> Other Disciplines of Environmental Sciences, Resource Sciences submitted time 2021-03-02 Cooperative journals: 《干旱区研究》
Abstract：选取不同年限退/弃耕地（退耕1 a、2 a、4 a、8 a、13 a、20 a、30 a、40 a和CK）为研究对象，采用时空替代法，分析了不同年限退/弃耕地植被群落特征和土壤理化性质及其相关性。结果表明：（1）石羊河下游青土湖退/弃耕地40 a的植被恢复过程中，9个样方共出现15科29属43种植物，退/弃耕地物种构成表现为：多数种属于少数科、少数种属于多数科。植被演变分为：一年生草本和多年生植物快速生长期（1~2 a），一年生草本向多年生草本演变期（2~8 a），多年生草本向灌木演变期（8~20 a）和以灌木为主的稳定期（20~40 a）；（2）随退耕年限增加，土壤含水量呈先减小后增加最后波动式减小趋势，上层土壤含水量高于下层土壤含水量。各样方比例最大是细砂粒，粉粒次之，比例最小的是粗砂粒和黏粒，随退耕年限的变化，各粒径占比变化不大；（3）随退耕年限增加，土壤全氮和有机质均呈下降趋势，速效钾含量呈先增加后减小趋势，速效磷含量呈先减小后增加再减小趋势，表聚现象明显；（4）植被群落演替与土壤理化性质具有密切相关性。Margalef丰富度指数与土壤全氮和有机质呈极显著正相关关系，Shannon多样性指数与土壤容重和细砂粒呈显著的正相关关系，与土壤黏粒和粉粒呈显著负相关关系。退耕第4 a是青土湖退/弃耕地在恢复治理过程中关键时期。
Subjects: Biology >> Botany submitted time 2020-01-02 Cooperative journals: 《干旱区研究》
Abstract： 裸果木（Gymnocarpos przewalskii）起源于古地中海，为荒漠区少有的第三纪孑遗植物种。本文用2017年6月、7月和8月采集于甘肃安西自然保护区内的裸果木中龄和老龄植株叶片，分析自然干旱影响下叶片渗透调节物质及抗氧化酶活性的变化。结果表明：随着干旱程度的增加，裸果木叶片的可溶性蛋白（SP）显著积累，发挥着重要的渗透调节作用，中龄植株叶片的可溶性糖（SS）含量和老龄植株叶片的脯氨酸（Pro）含量先增加后显著降低，渗透调节作用有限。干旱加剧时，中龄植株叶片的超氧化物歧化酶（SOD）活性和抗坏血酸过氧化物酶（APX）活性呈明显的先增后降。严重干旱时，过氧化物酶（POD）活性和过氧化氢酶（CAT）活性明显增强，说明其通过4种酶的协同作用清除过剩的活性氧，减轻过氧化伤害；老龄植株叶片的CAT活性持续增强，APX活性明显的先升后降，POD活性在重度干旱时显著增强，主要通过这3种酶减轻膜系统伤害。丙二醛（MDA）含量则随干旱程度增大显著增加，膜脂过氧化程度不断加深。在相同的降雨条件下，裸果木中、老龄植株的Pro、SS、SP含量、POD和CAT活性、MDA含量对干旱的响应程度存在显著差异，隶属度函数评价法表明，老龄植株的抗旱能力大于中龄植株，表明裸果木的抗旱性随年龄的增大而提高。
Hits
Hits
Downloads
Comment