Study On In Vitro Culture Of Vetiveria Zizanioides And Physiological Effects Of Salt And Different PH Stresses On The Seedlings

Vetiveria zizanioides (L.) Nash by in vitro culture method can be propagated rapidly. In order to understand the induction differences of in vitro culture of V. zizanioides by different type and concentration of auxin and cytokinin, the experiment based on the node stem of V. zizanioides as explants for callus and adventitious buds induction was conducted. The explants were cultured on MS medium supplemented with different types and concentrations of auxin and cytokinin. The results showed that, MS medium supplemented with the combination of 2,4-D 2.0 mg/L and TDZ 0.5 mg/L was better to callus induction with node stem as explants. The better adventitious buds induction medium was MS medium with IBA 1.0 mg/L and 6-BA 3.0 mg/L, the number of the induced adventitious buds was about 4 to 5 and the inductivity of the adventitious buds was about 28.5% to 37.5%. The better root induction medium was MS medium with IAA 0.5 mg/L and 6-BA 3.0 mg/L.Under different concentrations of salt stress (0-200 mmol/L NaCl), the changes in physiological and biochemical indexes of V. zizanioides seedlings were investigated. The results showed that, with the increase of salt concentration, the chlorophyll content decreased in leaves of V. Zizanioides seedlings, with significant difference in comparison with the control (P< 0.05). Malondialdehyde (MDA) content in leaves and roots were increased, but the increase of MDA content in leaves was more obvious. When the salt concentration was 100 mmol/L, the relative electrolytic leakage and MDA content in roots of V. Zizanioides seedlings did not change significantly. With the concentration increases (200 mmol/L), the proline contents in leaves and roots of V. Zizanioides seedlings both rised, and compared to a significant increase in proline content in leaves and roots of the control group.Under nutritional solution culture, the effects of different pH (2.0-11.0) stresses on plant appearance and physiological characteristics were investigated in V. zizanioides seedlings. The results showed that, under strong alkali (pH11.0, pH10.0) and strong acidic (pH2.0, pH3.0) stresses, the heavy injury on seedlings of V. zizanioides seedlings compared with control (pH6.5) was occurred, which was resulted from the leaf chlorosis, significant decrease of water content and chlorophyll content in leaves, obvious increase of relative electrolytic leakage and MDA content in leaves, and the lower roots activity, maximum roots length, and less fibrous roots; while pH values varied from 4.0 to 9.0, the changes in leaves water content and relative electrolytic leakage were not significantly different in comparison with the control (pH6.5), and the variability in roots morphology and activity were moderate, the stressful phenomenon on V. zizanioides seedlings was relatively slighter.