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本文研究了低温、高温、紫外线和暗培养对二倍体、三倍体和四倍体大花蕙兰类原球茎(PLBs)增殖和分化的影响。结果表明,10℃下培养,四倍体PLBs增殖率最高;35℃下培养20 d,三倍体和四倍体PLBs死亡率显著低于二倍体,表明多倍体PLBs具有更强的抵御低温和高温能力。紫外灯下培养30 d,PLBs的增殖率大小依次是四倍体>三倍体>二倍体,与日光灯下相反,说明多倍体PLBs对紫外线耐受力比二倍体强。暗培养30 d,二倍体PLBs增殖率和芽分化率明显提高,而三倍体和四倍体增殖率没有明显变化,其芽分化率明显降低。在黑暗条件下继代培养30 d,二倍体PLBs增殖率降低,但降幅小于三倍体和四倍体,芽分化率则进一步提高,而三倍体和四倍体PLBs芽分化率进一步降低,表明多倍体PLBs对黑暗的耐受力变弱。多倍体PLBs中SOD、POD和CAT的活性均高于二倍体,MDA含量低于二倍体,抗氧化酶系及MDA的变化是导致多倍体PLBs抗性增强的重要原因。
In this paper, the effects of low temperature, high temperature, UV and dark culture on the proliferation and differentiation of diploid, triploid and tetraploid Cymbidium protocorms (PLBs) were studied. The results showed that tetraploid PLBs had the highest proliferation rate at 10 ℃. The mortality of triploid and tetraploid PLBs was significantly lower than that of diploid at 20 ℃ for 35 d, indicating that polyploid PLBs have stronger resistance Low temperature and high temperature capability. Under UV light for 30 days, the proliferation rate of PLBs was tetraploid> triploid> diploid, which was the opposite of fluorescent light, indicating that polyploid PLBs are more resistant to ultraviolet light than diploid. Under dark culture for 30 days, the proliferation rate and bud differentiation rate of diploid PLBs increased obviously, but the proliferation rate of triploid and tetraploid did not change obviously, and the rate of bud differentiation was significantly decreased. The proliferation rate of diploid PLBs decreased in the dark for 30 days, but the decline rate was smaller than that of triploid and tetraploid, and the rate of bud differentiation was further increased, while the differentiation rate of triploid and tetraploid PLBs buds was further reduced , Indicating that polyploid PLBs are less resistant to darkness. The activities of SOD, POD and CAT in polyploid PLBs were higher than those in diploid, and the content of MDA was lower than that in diploid. The changes of antioxidant enzymes and MDA were the important reasons leading to the increase of polyploid PLBs.