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一个谷子新耐旱性突变体(drm)光合特性与抗旱性能分析

Photosynthesis and drought tolerance analysis of a new drought-resistant mutant (drm) of Setaria italica P. Beauv.

  • 摘要: 谷子(Setaria italica P. Beauv.)作为C4模式植物,具有较强的抗旱性,但干旱仍是制约其生长和产量的重要因素。为探究谷子耐旱性突变体(Drought-resistant mutant)的抗旱生理机制,以野生型‘豫谷28’和其耐旱性突变体(drm1-1)为材料,采用盆栽法分析了干旱胁迫下野生型与drm1-1在孕穗期和花后10 d的光合特性和抗旱性。结果显示,在正常条件下,drm1-1诱导了谷子光合作用相关的磷酸烯醇式丙酮酸羧化酶基因pepc、丙酮酸磷酸双激酶基因ppdk以及苹果酸酶基因nadp-me的表达,显著提高了相应酶的活性,也使得drm1-1的光合速率较野生型显著提高。在干旱胁迫条件下,drm1-1的光合速率和叶绿素荧光参数与正常条件相比,下降幅度显著小于野生型,具有显著的光合优势,同时drm1-1叶片的相对含水量与正常条件相比,下降的幅度显著小于野生型,而渗透调节物含量及抗氧化物酶活性均较野生型显著增加;且drm1-1的持水能力及抗旱性能更强。产量性状分析表明,干旱胁迫条件下drm1-1具有突出的产量优势。

     

    Abstract: Although Foxtail millet (Setaria italica P. Beauv.) is a relatively drought-tolerant C4 model plant, drought is still an important factor restricting its growth, physiology, and production. To explore the physiological mechanism of drought-resistant millet mutants, we used wild-type ‘Yugu 28’ and its drought-resistant mutant (drm1-1) to explore their photosynthesis and drought tolerance characteristics when potted at the shooting stage and 10 d after flowering under drought-stressed conditions. Results showed that drm1-1 induced higher expression of photosynthesis-related genes, such as pepc (phosphoenolpyruvate carboxykinase), ppdk (pyruvate orthophosphate dikinase), and nadp-me (nadp-malic enzyme), and higher enzymatic activity of photosynthesis-related enzymes, which promoted greater photosynthesis under non-drought-stressed condition. Under drought-stress condition, the photosynthetic rate and chlorophyll fluorescence parameters of drm1-1 decreased significantly less than the wild-type plants under non-drought-stressed condition, showing a significant photosynthetic advantage. The leaf relative water content of drm1-1 also showed a significantly lower decrease than the wild-type plants under non-drought-stressed condition, and drm1-1 showed higher osmoregulation substance content and antioxidant enzyme activity than the wild-type plants, suggesting enhanced water holding capacity and drought resistance. Based on yield trait analysis, drm1-1 also exhibited outstanding yield advantages under drought stress condition.

     

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