超表达AVP1基因提高转基因百脉根的耐盐性和抗旱性

本研究以超表达拟南芥液泡膜H＋-焦磷酸酶编码基因AVPI的转基因百脉根为材料，对其耐盐性和抗旱性进行了检测。结果显示：在200mmol·L^-1 NaCl下处理或自然干旱7d后，转基因植株的生长虽然受到抑制，但受抑程度明显低于野生型植株，前者叶片相对含水量比后者分别高18％和14％，净光合速率分别高20％和21％，而MDA含量则分别低35％和27％，相对质膜透性分别低28％和27％。此外，随着盐和干旱胁迫的加剧，与野生型植株相比，转基因植株体内积累了更多Na＋、K＋和Ca2＋。以上结果表明，AVPI基因的超表达可能提高了百脉根细胞Na＋区域化能力，既减轻了过量Na＋对细胞质的毒害作用，也提高了植株的渗透调节能力，从而增强了百脉根的耐盐性和抗旱性。

Overexpression of AVP1 Enhanced Salt and Drought Tolerance of Transgenic Lotus corniculatus L.

The Arabidopsis thaliana vacuolar H＋-pyrophosphatase （H＋-PPase） gene （AVP1） was overexpressed in Lotus corniculatus could enhance salt and drought tolerance of transgenic plants. The results indicated that the growth of transgenic lines was inhibited in the presence of 200 mmol.L-1 NaCl or under a water-deprivation condition after 7 days, while the wild-type plants suffered from much more serious growth inhibition. Under 200 mmol.L-1 NaCl or water-deprivation treatments, transgenic plants retained more water in leaves and higher photosynthesis activity compared with wild-type whereas the content of MDA and the relative membrane permeability of transgenic plants was lower than wild-type. Furthermore, under salt or water-deficit stress, transgenic plants accumulated more Na＋, K＋ and Ca2＋ in their leaves and roots. These results demonstrated that overexpression of AVP1 gene might enhance compartmentalization of Na＋ in vacuole, which not only reduced the damage of excess Na＋ in the cytosol under salt stress, but also enhanced the osmoregulation capacity of cells, and therefore improved salt and drought resistance of transgenic L. corniculatus.