瓶内接种菌根真菌对毛棉杜鹃生长与抗性酶的影响

Impact of Inoculation with Mycorrhizal Fungi in vitro on Growth and Resistant Enzymes of Rhododendron moulmainense

【目的】研究毛棉杜鹃(Rhododendron moulmainense)的接种效应,筛选较佳的菌种,为毛棉杜鹃高效育种提供参考,并初步揭示菌根提高植株抗性的机理。【方法】选用7种从野生毛棉杜鹃中分离并鉴定的杜鹃类真菌回接到毛棉杜鹃无菌组培苗中,定期观察生长情况,测定苗高与生物量增长率、菌根侵染率、病情指数、PAL酶与LOX酶活性。【结果】(1)对照组2周后枯萎,而接菌组均生长良好。(2)7号菌组苗高生长率与生物量增重率均为最高,分别为71.81%与83.62%,其次是17号与14号处理组。(3)16号的菌根侵染率最高,1号菌种最低。7号的病情指数最低,5号、3号病情指数最高。各接菌处理组的PAL酶和LOX酶活性均高于CK组,16号PAL酶、LOX酶活性最高,为4.82与0.88 U/mg,1号、5号、17号PAL酶活性最低,为1.90~2.20 U/mg,1号、3号LOX酶活性最低,为0.29~0.38 U/mg。相关性分析表明,侵染强度与PAL酶活性和LOX酶活性均有显著正相关,而病情指数与侵染强度、PAL酶活性和LOX酶活性均呈负相关。【结论】7种真菌均可与毛棉杜鹃无菌组培苗形成菌根共生体,但不同菌种对宿主植物的生长影响有差异,7号(Bionectria ochroleuca)为最优的菌种,14号(Aspergillus sydowii)与17号(Paecilomyces javanicus)菌种为次优菌种。菌根侵染强度越大更加有益于PAL酶和LOX酶的产生,对植物的抗性与生长可能有一定程度的影响,但与真菌的种类有关。

【Objective】The study of Rhododendron moulmainense inoculation with mycorrhizal fungi was conducted to select the better strains,and to provide the reference for improving breeding efficiency,also to reveal the mechanism of improving plant resistance by mycorrhizal fungi. 【Method】7 kinds ericoid mycorrhizal fungis,separated from wild Rhododendron moulmainense,were used to inoculate Rhododendron moulmainense tissue culture seedling. Growth situation was observed regularly,and height growth rate,biomass growth rate,mycorrhizal infection rate,disease index,PAL and LOX activity were determined.【Result】（ i） Plants of control group were wizened after 2 weeks,but plants of mycorrhizal inoculation treatment were viable.（ ii） Height growth rates and biomass growth rates of No. 7 treatment were the highest,71. 81 % and 83. 62 % respectively,No. 17 and No. 14 treatment fllowed. Mycorrhizal infection rates of No. 16 treatment were the highest,No. 1 treatment were the lowest. Disease indexes of No. 7 were the lowest,No. 5 and No. 3 were the highest. PAL and LOX activity of each mycorrhizal inoculation treatment all higher than control group. PAL and LOX activity of No. 16 treatment were the highest,4. 82 and0. 88 U/mg respectively,PAL activity of No. 1,No. 5,No. 17 were the lowest,1. 90-2. 20 U/mg,LOX activity of No. 1,No. 3 were the lowest,0. 29-0. 38 U/mg. The correlation analysis showed that,colonization intensity were positively correlated with PAL and LOX activity significantly,but disease index were negatively correlated with PAL and LOX activity. 【Conclusion】Each of the 7 kinds ericoid mycorrhizal fungi could form mycorrhizal symbionts with Rhododendron moulmainense,but different fungis had different impact on growth of host plants,the result showed that,No. 7（ Bionectria ochroleuca） was the optimal fungi,No. 14（ Aspergillus sydowii） and No. 17（ Paecilomyces javanicus） were the second choices. Higher mycorrhizal infection rate helped to improve PAL and LOX activity. It may have an impact on resistant and growth of plants,but resistant and growth of plants were more impacted by species of fungi.