水稻免疫育苗的抗性研究

MECHANISMS OF IMMUNIZATION OF RICE SEEDLINGS

将稻田土和病稻苗上分离的Ｆｕｓａｒｉｕｍｅｑｕｉｓｅｔｉ，Ｆ．ｏｘｙｓｐｏｒｕｍ，Ｆ．ｇｒａｍｉｎｅａｒｕｍ和Ｒｈｉｚｏｃｔｏｎｉａｓｏｌａｎｉ，接种在免疫育苗法和普通旱育苗法培育的秧苗上。免疫育苗的秧苗提高抗病力９５．５％～９７．８％。测定其秧苗接种病原菌后防御酶系的动态表明：１．过氧化物酶活性峰比对照提前３６ｈ，且峰值高；２．超氧化物歧化酶活峰比对照提前４ｈ；３．苯丙氨酸解氨酶的活力比对照高１倍多。同时免疫育苗秧苗新陈代谢旺盛、生理活性高。表现在：１．叶片叶绿素含量高（３．１２ｍｇ／ｍｌ）、光合作用强度大（８８７ｍｏｌＯ２／ｇ．ｈ），因而干物质积累多；２．根系发达，单株根数比普通旱育秧苗多３．９条／株；３．根系色白有弹性，活力强，对α－萘胺氧化力达６０μｇ／ｇ．ｈ，提高３０％；４．束缚水含量达６４．８９％，显著高于普通旱育苗；５．根冠比比普通旱育苗高２８％。

The rice seedling disease causal agents: Fusarium equiseti, F. oxysporum, F. graminearum and Rhizoctonia solani isolated from paddy rice soil and diseased rice seedlings, were used to inoculate the Immunization of Rice Nursery (IRN) seedlings and Paddy Soil Land Nursery (PSLN) seedlings (control). It was indicated that the disease resistance of IRN seedlings was 95.5～97.8% higher than that of PSLN seedlings. By testing the dynamics defensive enzyme systems in both IRN and PSLN seedlings after inoculation with the causal agents, the results showed that under the elicitment by the causal agents the enzyme activity peaks of peroxidase (PO) and superoxide dismutase (SOD) in IRN seedlings appeared 36 hrs and 4 hrs earlier than those in PSLN seedlings, respectively, and that the ratio activity of phinylalaminase in IRN seedlings was 2 times more than that in PSLN seedlings. In addition, IRN seedlings metabolized faster and showed higher physiological activity. The physiological traits of IRN seedlings were as follows: (1) the higher amount of chlorophyll (3.12mg/ml), strong photosynthetic ability (887.0 mol O 2/g.hr), thus dry matter accumulation was much faster. (2) Dense root system (11.5 roots per plant), there was 3.9 roots per plant more than that of control. (3) The α Naphthylamine oxidation was 60.0 μg/g.hr which was 30% higher than that of control.