Abstract: Physiological and biochemical influences of plant growth regulators(6-BA and GA3) on red-stem Dendrobium officinale seedlings under salt stress were performed. The results showed that low concentration of 6-BA and GA3 remarkably increased stem growth rate of red-stem D. officinale under salt stress, but reduced root growth rate. And GA3 had more effects than 6-BA in root growth rate. With the increase of 6-BA concentration, the chlorophyll contents in leaves of red-stem D. officinale displayed a high-low trend, and the carotenoid contents displayed a low-high-low trend, while high concentration of GA3 increased the contents of chlorophyll and carotenoid; Low concentration of 6-BA increased the content of soluble sugar in leaves of red-stem D. officinale under salt stress, while other concentrations of 6-BA and GA3 reduced the contents of soluble sugar. The results revealed that treatments of appropriate concentrations of exogenous plant hormones can protect the seedlings of red-stem D. officinale from hurt caused by salt stress by improving the photosynthetic pigment synthesis and soluble sugar accumulation.

Key words: red-stem Dendrobium officinale, plant growth regulator, salt stress

摘要： 以红杆铁皮石斛Dendrobium officinale为材料，研究植物生长调节剂6-苄氨基腺嘌呤(6-BA)和赤霉素(GA3)对其幼苗在NaCl胁迫下的生理生化影响。结果表明，盐胁迫下，低浓度 6-BA和GA3处理均可不同程度地提高红杆铁皮石斛幼苗的茎生长率，抑制根的伸长，且GA3抑制效果大于6-BA；随着6-BA浓度增加，盐胁迫下红杆铁皮石斛叶片叶绿素含量降低，类胡萝卜素含量则呈先升后降的趋势，而较高浓度GA3(4.0 mg·L-1)处理同时提高叶绿素和类胡萝卜素含量；低浓度6-BA(2.0 mg·L-1)处理能提高红杆铁皮石斛叶片可溶性糖含量，相同浓度GA3处理则降低可溶性糖含量，但高浓度GA3处理的可溶性糖含量与对照无显著差异。因此，添加适当浓度的植物生长调节剂能提高光合色素及可溶性糖的合成与积累，从而缓解盐胁迫对红杆铁皮石斛植株的伤害。

关键词: 红杆铁皮石斛, 生长调节剂, 盐胁迫