模拟干旱胁迫对巴东木莲种子萌发和芽苗生长的影响

Effects of simulated drought stress on seed germination and seedling growth of Manglietia patungensis

关键词:  巴东木莲, 干旱胁迫, 种子萌发, 芽苗生长, 芽苗生理

Key words:  Manglietia patungensis, drought stress, seed germination, bud seedling growth, bud seedling physiology

摘要:

巴东木莲原生种群天然更新差,林下鲜见更新幼苗或幼树。为探究其种子萌发和芽苗在生长期对干旱胁迫的耐受性,该文以巴东木莲种子为材料,采用不同质量浓度的聚乙二醇(PEG-6000)模拟干旱胁迫,分析干旱胁迫对其种子萌发、芽苗生长及其相关的生理生化指标的影响。结果表明:(1)不同质量浓度的PEG溶液对巴东木莲种子萌发和芽苗生长产生显著影响(P<0.05),萌发率和存活率随着PEG质量浓度的增加而逐渐降低,当PEG质量浓度≥301 g·L^-1时,种子萌发受到抑制,且萌发时间明显推迟。(2)随着干旱胁迫程度的增加,巴东木莲芽苗叶绿素含量逐渐降低; 可溶性蛋白含量和超氧化物歧化酶(SOD)活性表现出不同程度的先升高后降低趋势; 而脯氨酸(Pro)和丙二醛(MDA)含量及过氧化物酶(POD)和抗坏血酸过氧化氢酶(APX)活性呈现逐渐升高的趋势。综上分析得出,巴东木莲种子萌发及芽苗的生长对水分需求明显,虽可通过渗透调节和提高保护性酶活性来适应一定程度的干旱胁迫,但在繁育过程中,需防止干旱损伤。该研究结果可为巴东木莲种子繁育更新提供理论依据,有助于巴东木莲种群的扩大。

Abstract:

Native communities of Manglietia patungensis are difficult to regenerate naturally, and seedlings or saplings are rarely found under the forest. To explore the tolerance of seed germination and the growth period of bud seedlings under drought stress, we used the seeds of M. patungensis with different mass concentrations of polyethylene glycol(PEG-6000)to analyze the effects of drought stress on seed germination, sprout growth and related physiological and biochemical indexes under different simulate drought treatments. The results were as follows:(1)The concentration of PEG solution had a significant impact on seed germination and sprout growth of M. patungensis(P <0.05). The germination and survival rate gradually decreased with the increase of PEG mass concentration. When the PEG mass concentration was more than 301 g·L^-1, seed germination was inhibited, and the germination time was significantly delayed.(2)The chlorophyll content of M. patungensis buds decreased gradually with the increase of the degree of drought stress; the content of soluble protein and the activity of superoxide dismutase(SOD)enzyme increased and then decreased; While the contents of proline(Pro), malondialdehyde(MDA)and the activities of peroxide(POD)and ascorbate perixide(APX)enzyme increased. In summary, the water demand for seed germination and bud growth of M. patungensis is obvious. Although it can adapt to a certain degree of drought stress through osmotic adjustment and increase protective enzyme activity, it is necessary to prevent drought damage in the breeding process. The research provides a theoretical basis for seed reproduction and regeneration of M. patungensis, and contributes to the population expansion.