热带植物海巴戟抗寒株系选育

为了选育海巴戟（Morinda citrifolia）抗寒株系，拓宽种植范围，在云南元江选择8株海巴戟，采用石蜡切片法观察叶片解剖结构，并测量叶片的过氧化氢酶（CAT）、过氧化物酶（POD）、超氧化歧化酶（SOD）活性和丙二醛（MDA）含量，对抗寒株系的甘油-3-磷酸酰基转移酶（GPAT）活性和GPAT表达进行定量分析。结果表明，叶片解剖结构表明有4株海巴戟叶片的栅海比较高，细胞结构紧密，确定为抗寒性优良的候选株系（5、6、8和12号）。5号植株叶片经低温处理后的CAT、POD、SOD活性较高，MDA含量较低，确定为抗寒株系，且低温处理后5号植株叶片的GPAT活性和GPAT基因表达水平均高于不抗寒材料。因此，海巴戟叶片通过增加栅海比和细胞结构紧密度，同时GPAT基因迅速应答来提高抗寒性。

Selective Breeding of Cold-resistant Strain for Tropical Plant Morinda citrifolia

In order to select cold-resistant lines of Morinda citrifolia for widen the range of planting, the leaf anatomic structures of eight plants growing in Yuanjiang, Yunnan, were observed by paraffin section method, and the activities of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and malondialdehyde (MDA) content were measured, and then, glycerol-3-phosphate acyltransferase (GPAT) activity and GPAT gene expression in cold-resistant lines were quantitatively analyzed. The results showed that the leaves of 4 lines (No. 5, 6, 8, 12) had high ratio of palisade tissue to spongy tissue (P/S) with compact cell structure and low porosity, showing a certain cold resistance. The activities of CAT, POD, and SOD of No. 5 leaves were high, and the content of MDA was low after treated at low temperature, indicating that No. 5 was a cold-resistant line. After low temperature treatment, the GPAT activity and GPAT gene expression in No. 5 were higher than those in other plants. Therefore, the cold resistance of M. citrifolia leaves was improved by increasing P/S and cell structure tightness, as well as the rapid response of GPAT gene.