茉莉酸在橡胶树体内移动的放射自显影研究

Exogenous Jasmonic Acid Transportation Revealed by Autoradiography in Hevea brasiliensis

以巴西橡胶树(HeveabrasiliensisMull.Arg.)无性系ZY7-33-97萌条为材料,采用石蜡切片的放射自显影技术,研究外源茉莉酸在植物体内的移动规律。对3H-JA喂饲的材料采用2%(质量浓度)EDC(1-乙基-3-[3-(二甲胺基)丙基]碳二亚胺盐酸盐)+4%(体积分数)戊二醛(0.1mol/L磷酸盐缓冲液,pH7.2)固定24h,进行石蜡切片的放射自显影。结果表明,在1min内,施用部位的表皮、皮层、韧皮部和木质部中均有3H-JA分布;5￣30min内,在施用部位及其上下5cm和10cm处的茎中,木质部和韧皮部中均含有3H-JA,但在表皮和皮层薄壁细胞中则无。3H-JA分布在筛管、次生韧皮部的薄壁细胞和射线细胞、形成层区以及导管、次生木质部的薄壁细胞和射线细胞,其中,在韧皮部和木质部的射线细胞及筛管、导管壁周围分布最多。JA在橡胶树内可快速通过韧皮部经由形成层径向运输到木质部,同时,JA能通过木质部和韧皮部进行纵向长距离双向运输。

The transportation of exogenous jasmonic acid in Hevea Clone ZY7-33-97 （Hevea brasiliensis Mull. Arg.） was studied by using autoradiography in paraffin section. Samples fed with ^3H-JA were fixed for 24 hours in 2 % EDC [ 1-Ethyl-3-（3-dimethyl aminopropyl）-carbodiimide hydrochloide] ＋ 4 % glutaraldehyde in 0.1 mol/L phosphate buffer at pH 7.2 at a room temperature. In the cross sections of the samples from treated site, ^3H-JA was detected from epidermis to Xylem 1 minute after being fed. In the cross sections of the samples from the upper and lower parts 5 cm and 10 cm from the treated site respectively, ^3H-JA was present exclusively in the phloem and xylem, and no ^3H-JA was found in epidermis and cortex 5 minutes and 30 minutes after feeding. In the phloem and xylem of the treatea sites, a lot of ^3H- JA was detected in the sieve tubes, the secondary phloem parenchyma cells, the secondary phloem ray parenchyma cells, cambium regions, vessel wall, the secondary xylem parenchyma cells and the secondary xylem ray Parenchyma cells, especially in the phloem and xylem ray parenchyma cells, vessel wall and sieve tubes. Our results showed that the transportation of JA from phloem to xylem occurred mainly through ray parenchyma cells and cambium regions, and that JA could be transported rapidly upwards and downwards through vessel tube and sieve tube. JA transportation is likely to be through ray parenchyma cell, vessel tube and sieve tube in H. brasiliensis.