外源一氧化氮对铁皮石斛原球茎生长和多糖积累的影响

以硝普钠（SNP）为一氧化氮（NO）供体，研究了不同浓度的外源NO对铁皮石斛原球茎生长、叶绿素含量、蔗糖合成酶（SS）活性和多糖积累的影响。结果总体表现为低浓度的SNP有利于铁皮石斛原球茎的生长，而高浓度的SNP可以促进多糖的合成。在添加0.50 mmol·L-1SNP的培养基中培养28 d时其干质量比对照高36.9％，总叶绿素含量在14 d时为对照的1.33倍；在添加1.00 mmol·L-1 SNP的培养基中培养7 d时其多糖含量为对照的1.59倍，同时SS活性显著升高。综合多糖产量来看，0.50 mmol·L-1SNP效果最佳，在处理期间显著高于其他处理，且对其干质量、叶绿素含量、SS活性和多糖积累均有促进作用。添加NO清除剂（cPTIO）后，铁皮石斛原球茎的生长、SS活性和多糖合成受到抑制。

Effects of exogenous nitric oxide on growth and polysaccharide accumulation of protocorm like bodies from Dendrobium officinale

Sodium nitroprusside（SNP） was used as nitric oxide（NO） donor， the effects of different concentrations of exogenous NO on the protocorm like bodies（PLBs） from Dendrobium officinale， including the growth， chlorophyll content， the activity of sucrose synthase （SS） and the accumulation of polysaccharide were studied. The results showed that a low level of SNP was beneficial for the growth of protocorm like bodies， but the high level of SNP could promote the synthesis of polysaccharide. The dry weight of PLBs cultured in 0.50 mmol·L-1 SNP medium was 36.9% more than its control on the 28th day， and the total chlorophyll content on the 14th day was 1.33 times of the control. The polysaccharide content in the treatment of 1.00 mmol·L-1 SNP was 1.59 times of the control， while the activity of sucrose synthetase significantly increased. Taken together， 0.50 mmol·L-1 SNP showed the best effect， which could promote the dry weight， chlorophyll content， sucrose synthetase activity and the content of polysaccharide， and the above indexes were significantly higher than other treatments. While cPTIO， nitric oxide scavenger， was added， the growth of PLBs， sucrose synthase activity and polysaccharide accumulation were all inhibited.