Yan Xing-Fu, Deng Xiao-Juan, Wang Jing, Zhou Li-Biao, Zhang Jin-Feng, Luo Yong-Hong
College of Biological Science and Engineering, North Minzu University/Key Laboratory of Ecosystem Modelling and Applications of National Ethnic Affairs Commission of China, Yinchuan 750021, China.
Ying Yong Sheng Tai Xue Bao. 2020 Oct;31(10):3331-3339. doi: 10.13287/j.1001-9332.202010.006.
The effects of seed size and drought stress on the growth and physiological characteristics of seedlings were investigated under shading conditions of a pot experiment in greenhouse. There were four treatments, including 80% field water content (FWC), 60% FWC, 40% FWC, and 20% FWC [CK, light drought stress (LDS), medium drought stress (MDS), and high drought stress (HDS), respectively]. The results showed that leaf area per plant, total dry mass, and root-shoot ratio of seedlings regenerated from large seeds (3.05±0.38 g) were significantly higher than those from small seeds (1.46±0.27 g) in all four treatments. Shoot height, basal stem diameter, leaf number, specific leaf area, relative growth rate, and net assimilation rate of the seedlings from large seeds were higher than those of seedlings from small seeds under the treatments of LDS, MDS and HDS. Activities of peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) in large-seeded seedlings were higher than those of small-seeded seedlings under all treatments, while the contents of MDA, soluble protein, free proline, and total chlorophyll of large-seeded seedlings were higher than those of small-seeded seedlings only under some drought stress treatments. All growth parameters except the root-shoot ratio decreased with the increases of drought stress. The HDS treatment resulted in 19.4% and 20.0% decline in total dry mass of large- and small-seeded seedlings respectively, compared with those of CK. With increasing drought stress, the activities of POD, CAT, and SOD decreased after an initial increase. POD activity of large- and small-seeded seedling under MDS treatment was 126.7% and 142.1% higher than CK, while CAT was 170.0% and 151.9% higher than CK, respectively. However, the MDA content of seedlings from large and small seeds under HDS treatment was 86.5% and 68.9% higher than that of CK, respectively. The contents of soluble protein, free proline, and total chlorophyll rose at first and then fell with increasing drought stress, and soluble protein content in large- and small-seeded seedlings experienced MDS enhanced 320.7% and 352.7%, respectively. Those results indicated that large-seeded seedlings of . had stronger drought tolerance than small-seeded seedlings due to their growth and physiology advantages. Large-seeded seedlings with stronger resistance to drought stress should be applied to artificial regeneration of the degraded secondary . plantations.
在温室盆栽试验的遮荫条件下，研究了种子大小和干旱胁迫对幼苗生长及生理特性的影响。试验设置了四个处理，分别为80%田间持水量（FWC）、60% FWC、40% FWC和20% FWC [分别为对照（CK）、轻度干旱胁迫（LDS）、中度干旱胁迫（MDS）和重度干旱胁迫（HDS）]。结果表明，在所有四个处理中，由大种子（3.05±0.38 g）再生的幼苗单株叶面积、总干质量和根冠比均显著高于小种子（1.46±0.27 g）再生的幼苗。在LDS、MDS和HDS处理下，大种子幼苗的苗高、基茎直径、叶片数、比叶面积、相对生长速率和净同化率均高于小种子幼苗。在所有处理下，大种子幼苗中过氧化物酶（POD）、过氧化氢酶（CAT）和超氧化物歧化酶（SOD）的活性均高于小种子幼苗，而仅在某些干旱胁迫处理下，大种子幼苗中丙二醛（MDA）、可溶性蛋白、游离脯氨酸和总叶绿素的含量高于小种子幼苗。除根冠比外，所有生长参数均随干旱胁迫的增加而降低。与CK相比，HDS处理使大、小种子幼苗的总干质量分别下降了19.4%和20.0%。随着干旱胁迫的增加，POD、CAT和SOD的活性在最初升高后下降。MDS处理下大、小种子幼苗的POD活性分别比CK高126.7%和142.1%，而CAT分别比CK高170.0%和151.9%。然而，HDS处理下大、小种子幼苗的MDA含量分别比CK高86.5%和68.9%。可溶性蛋白、游离脯氨酸和总叶绿素的含量随干旱胁迫的增加先升高后降低，MDS处理下大、小种子幼苗的可溶性蛋白含量分别提高了320.7%和352.7%。这些结果表明，由于其生长和生理优势，[植物名称]的大种子幼苗比小种子幼苗具有更强的耐旱性。具有更强抗旱胁迫能力的大种子幼苗应应用于退化次生[植物名称]人工林的更新。
