干旱胁迫对洋竹草形态、生理及存活率的影响

The growth and survival rate of Callisiarepens under drought stress

摘要:

【目的】明确洋竹草(Callisia repens)对干旱胁迫的响应。【方法】通过盆栽试验，对洋竹草分别在干旱 170、180、190、200 和 210 d 时的水分变化及生理响应进行研究。【结果】(1)随着干旱时间的延长，洋竹草盖度从 170 d 时的 35. 2% 下降到 210 d 时的 10. 3%，具有显著差异(P ＜ 0. 05)，并伴随叶片萎蔫、叶片边缘卷缩、叶片颜色变淡等叶片形态的改变。(2)随着干旱时间的增加，叶片含水量和叶绿素含量均呈现逐步下降的趋势。其中叶片含水量从 170 d 时的 18. 1% 下降到 210 d 时的 16. 6%，叶绿素 a 含量从 170 d 时的 0. 55 mg/g 下降到 210 d 时的 0. 25 mg/g，叶绿素 b 含量从 170 d 时的 0. 30 mg/g 下降到 190 d 时的 0. 20 mg/g，均达到显著差异(P＜0. 05)。而可溶性糖含量和脯氨酸含量则逐步上升，其中脯氨酸含量从 170 d 时的 7. 29 μg/g 上升到 210 d 时的 9. 03 μg/g，可溶性糖含量则从 170 d 时的 3. 48 μg/g 上升到 210 d 时的 4. 87 μg/g。而叶片相对电导率则呈现不规则变化，但 200 d(44. 34%)和 210 d (43. 94%)时的电导率均显著于 170 d(38. 30%)和 180 d(37. 74%)。(3)复水试验表明，干旱 170、180、 190、200 d 时，洋竹草的存活率均高达 100%，干旱 210 d 时存活率达 77. 78%。【结论】洋竹草可通过自身形态与生理机制的调节来提高抗旱性，耐干旱胁迫的时间超过 210 d。本研究为洋竹草在干旱胁迫下的形态及生理响应机制提供理论依据，为进一步认识洋竹草的抗旱性和指导洋竹草屋顶绿化应用和生产实践提供参考资料。

Abstract:

To better understand the responses of Callisia repens to prolonged drought stress，pot experiment was performed to study the changes of water content and physiological responses of C. repens under prolonged drought stress for 170，180，190，200 and 210 d. The results showed that：(1) As the drought persistent，the coverage of C. re- pens decreased significantly (P＜0. 05) from 35. 2% at the 170th day to 10. 3% at the 210th day which was accom‐ panied by morphological changes such as leaf wilting，leaf margin curled and leaf color diminish.(2) Leaf water con‐ tent and chlorophyll decreased as the drought persistent. The leaf water content decreased from 18. 1% at the 170th day to 16. 6% at the 210th day. The content of chlorophyll a decreased significantly (P＜0. 05) from 0. 55mg/g at the 170th day to 0. 25 mg/g at the 210th day，while the content of chlorophyll b decreased significantly (P＜0. 05) from 0. 30 mg/g at the 170th day to 0. 20 mg/g at the 190th day. While the content of proline and soluble sugar in‐ creased as drought persistent，in which proline increased from 7. 29 μg/g at the 170th day to 9. 03 μg/g at the 210th day，and soluble sugar content increased from 3. 48 μg/g at the 170th day to 4. 87 μg/g at the 210th day. Relative con‐ ductivity of C. repens leaf showed irregular changes，however，the relative conductivity of C. repens leaf both at the 200th day (44. 34%) and the 210th day (43. 94%) significantly higher than that at the 170th day (38. 30%) and the 180th day (37. 74%).(3) Rehydration test showed that the survival rate of persistent drought was 100% at 170， 180，190 and 200 days，and 77. 78% at 210 days. In summary，C. repens could improve its drought resistance through the regulation of its own morphology and physiological mechanism，and the longest duration time under prolonged drought were more than 210 days. Our study provides theoretical basis for the understanding of the morphological and physiological responses to continues drought stress. Italso provides a reference for further understanding of the drought resistance of C. repens and for the instruction of the application and practice for green roof.