文心兰原球茎形态发生与可溶性物质及抗氧化酶的关系

Soluble Substance and Antioxidase Activities Changes during Protocorm-like Body Morphogenesis in Oncidium

以文心兰切花品种‘南茜’无菌苗为材料,取其茎尖通过组织培养诱导形成原球茎和幼苗,观察并分析了原球茎各形态发生阶段的特征及其可溶性糖和蛋白质含量、抗氧化酶(POD、CAT和SOD)活性以及相关同功酶(POD、EST和SOD)的变化。结果显示:(1)文心兰原球茎形态发生可分为外植体期、外植体膨大期、愈伤组织期、原球茎形成期、原球茎成熟期、叶鞘伸展期、顶端腋芽发育期及幼苗期8个阶段。(2)可溶性糖和蛋白质含量均在叶鞘伸展期出现最大峰值;POD活性在外植体膨大期、CAT和SOD活性在愈伤组织期分别出现最大峰值。SOD同工酶的2条酶带在愈伤组织期到幼苗期交替出现;EST同工酶在原球茎形成期有2条特异酶带。研究表明,可溶性糖和蛋白质的含量以及POD、CAT、SOD活性的特异变化与文心兰茎尖脱分化及原球茎再分化的实现密切相关,不同类型的同工酶在原球茎同一发生阶段表现出较大差异,EST同工酶的2条特异酶带可作为原球茎形成的标志。

As the explants, the shoot tips of Oncidium ＇Gower Ramsey＇ plantlets in vitro were induced to produce protocorm-like bodies （PLBs） and regenerated plantlets. PLBs morphogenesis in different development stages was conducted, and soluble sugar and protein contents, POD, CAT and SOD activities and POD,EST and SOD isozymes during PLB morphogenesis were examined. The results showed that PLB morphogenesis was divided into eight stages including explant stage, expanding explant stage, callus stage, PLBs formation stage, mature PLBs stage, PLBs with one sheath-leaf stage, well-developed shoot apex stage and shoot developed stage. Soluble sugar and protein contents get the maximum in the PLBs with one sheath-leaf stage. POD activity get its maximum in expanding explant stage. Both CAT and SOD activities get their maximum in callus stage. Two bands of SOD isozymes happened from callus stage to shoot developed stage in turn,two specific bands of EST isozyme could be found in PLBs formation stage. The con- tents of soluble sugar and protein and the specific changes of POD,CAT and SOD activities were correlated with of shoot tips dedifferentiation and PLB redifferentiation. The different types of isozymes showed great difference at the same stage of PLBs. Two specific bands of EST isozyme could be regard as the marker of PLBs formation.