曼地亚红豆杉对自然降温的适应性研究

 以3年生的曼地亚红豆杉（Taxus media cv. Hicksii）为材料，对其在自然降温过程中的适应性进行了研究，结果表明：随着气温的降低，曼地亚红豆杉低温半致死温度不断降低，由秋季的-8.13 ℃降低到冬季最冷的1月中旬的-13.01 ℃；渗透调节物质可溶性总糖、可溶性蛋白质、游离脯氨酸含量均不同程度增加，而淀粉总含量降低；内源激素ABA含量不断升高，与低温半致死温度呈负相关（相关系数为-0.971 06），而ZRs、GA1/3、IAA含量降低，与低温半致死温度呈正相关（相关系数分别为0.949 72、0.813 6、 0.697 5）。综上所述，在自然降温过程中，这些物质的适应性变化导致了曼地亚红豆杉低温半致死温度的降低，从而使曼地亚红豆杉能很好地适应重庆栽培地的低温条件而安全过冬。

STUDIES ON THE ADAPTATION OF TAXUS MEDIA CV.HICKSII TO NATURAL TEMPERATURE REDUCTION

The adaptation of 3-year-old Taxus media cv. Hicksii leaves to natural temperature reduction was studied. The results showed that the semilethal low temperature（LT50）of Taxus media decreased increasingly　with the reduction of air temperature， from -8.13 ℃（in mid November ） to -13.01 ℃（in mid January ）. The contents of osmoregulatory substances such as soluble sugar, soluble protein and free proline increased to the the different degree, but the content of starch decreased. The contents of endogenetic hormones such as ABA rose continuously and negatively correlated to LT50 (the coefficient of correlation was -0.971 06). On the contrary， the contents of ZRs, GA1/3 and IAA reduced ，which the content of ZRs was positively correlated to LT50 (the coefficient of correlation was 0.949 72). In summary, the adaptive changes of these substances including osmoregulatory substances and endogenetic hormones of leaves of Taxus media cv. Hicksii led to the reduction of LT50, thus make Taxus media cv. Hicksii suit the low temperature condition cuitivated in Chongqing and pass the winter safely.