In Vitro Culture And In Vitro Flowering And Effects Of Microgravity On Seedling Growth Of Amaranthus Mangostanus L.

Seeds were used to study in vitro propagation and in vitro flowering of amaranth. The effects of environmental factors on the contents of pigment, soluble proteins and MDA were compared. And the effects of microgravity on the seedling growth and the contents of photosynthetic pigment were discussed. The main results were as follows:1 Establishment of in vitro regeneration system of amaranthSeeds were used to study in vitro propagation of amaranth. The results showed that the germination rate reached 87% or more on the MS medium after the sterilization treatment of 75% alcohol for 1min and 0.1% mercuric chloride for 8min. The best medium for adventitious bud induction from the hypocotyl with two cotyledons was MS medium with addition of 3.0 mg/L 6-BA, 0.2mg/L NAA, for propagation was MS medium with addition of 3.0mg/L 6-BA, 1.0mg/L IAA, with the proliferation coefficient of 13.02, for rooting was 1/2MS medium with addition of 0.2mg/L IBA, with the rooting rate of 20.35%. When the plantlets were transferred onto the garden soil, and the survival rate was up to 92.5% at proper temperature.2 In vitro flowering of amaranthThe affecting factors of in vitro flowering were studied on the establishment of efficient regeneration system. Based on the results, the in vitro flowering rate of amaranth had little difference between MS and 1/2MS basal media. Phytohormones had effects on the development of flowering. When either NAA or IBA alone was used, it could promote the in vitro flowering. When the concentration of 6-BA was 1.0mg / L, the in vitro flowering was the best, and the flowering rate was up to 58.7% after 50-60 days. In vitro flowering rate was no significant difference between the green light and white light treatments, but reduced by blue and red light treatments. The in vitro flowering was promoted under the light of 18h/d, and the flowering rate was up to 59.52% after 50-60d. The flowering rate was highest under pH5.8. The in vitro flowering rate was no significant difference when the seedling age of the explants at 15-21days; otherwise it decreased if seedling age was over this range. Without the next generations and continuously cultured for more than 3 months, the flowering rate could reach more than 95%. The flowers induced from the in vitro plantlets developed well and the fertilization and seed development were normal, and sometime the seeds even germinated into seedlings in the culturing bottle.The content of soluble protein, soluble sugar and the amaranth red pigment presented the tendency of increasing firstly, then decreasing during the plantlets transformed from vegetative growth to reproductive growth. The flower bud differentiation of amaranth maybe happened after the first next generations 19-28d.3 The effects of environmental factors on the accumulation of pigment of in vitro amaranth plantletsThe effects of the different environmental factors, such as temperature, pH value, light quality and photoperiod, were studied on the accumulation of pigment of in vitro amaranth plantlets. The results showed that both the chlorophyll synthesis and carotenoid synthesis were increased at 20±1℃, with pH 5.4, white light under 24 h/d. The content of anthocyanin was no significant difference at 20-32℃, higher between pH5.4 and pH5.8, higher through white light treatments, higher and not significant difference between 12 h/d and 18 h/d. The content of amaranth red pigment was higher at 20±1℃.4 The effects of environmental factors on the contents of soluble proteins and MDA of amaranth plantletsThe effects of the different environmental factors, such as temperature, pH values, light quality and photoperiod, were studied on the contents of soluble proteins and MDA of amaranth Test-tube seedlings. The research results showed that the contents of soluble proteins of amaranth plantlets increased at lower temperature and highest at 20±1℃. The content of soluble proteins was higher and not significant difference between pH6.2 and pH6.4. The soluble protein synthesis was promoted through red light treatment. The content of soluble proteins was highest with low-light under 24 h/d. The content of MDA was lowest through blue light treatment, was higher and not significant difference between 6h h/d and 12 h/d, and was highest at pH6.7.5 The simulate microgravity effects on amaranth seedling growthThe effects of simulate microgravity on the growth of amaranth seedlings and the content of photosynthetic pigment were studied. The results showed that the height of amaranth seedlings increased and the content of photosynthetic pigment decreased through the simulate microgravity effects. The content of chlorophyll decreased by 14.12% and carotenoid decreased by 11.68% after 40d simulated microgravity treatment.