Effects Of Auxin And Cytokinin On In Vitro Plant Regeneration Of Chinese Water Chestnut(Eleocharis Dulcis)

In this paper,water chestnut(Eleocharis dulcis(Burm.f.)Trin.ex Hensch,"Yuhang Dahongpao")was used as the material to investigate the effects of different concentrations of auxin IAA and NAA on the proliferation of in vitro buds and the leafy shoot growth and root induction of regenerated plants,and to select the optium concentration of auxin for growth of regenerated plants.The effects of combinations of different concentrations of TDZ and IAA on proliferation of regenerated buds,growth of regenerated plants and in vitro corm induction were also investigated.In addition,protein characteristics and evolutionary analysis were performed on the major gene family members that affect endogenous IAA biosynthesis,metabolism and action,as well as starch biosynthesis and metabolism.The results are as follows.(1)The appropriate auxin(IAA and NAA)concentration for bud proliferation was between 0.1 mg/L and 0.5 mg/L.However,it was observed that the addition of auxin alone had no significant effect on the bud proliferation of regenerated shoots.0.1 mg/L auxin was suitable for leaf generation,plant height and root growth of regenerated plants.We observed that the growth of regenerated plants was inhibited when the concentration of auxin exceeded 1.0 mg/L,and the growth of the regenerated plants stopped when the auxin concentration reached 2.0 mg/L.(2)The effect of 0.1 mg/L TDZ on bud proliferation of regenerated shoots was significantly better than the same concentration of 6-BA,and the combination of 0.1 mg/L TDZ and 0.5 mg/L IAA was suitable for bud proliferation.When the concentration of TDZ exceeded 0.5 mg/L,the adventitious buds induced was small,and some adventitious buds diedduring the subsequent growth;The combination of 0.1～0.3 mg/L TDZ and 0.1 mg/L IAA was suitable for leaf generation of regenerated plants,especially with 0.1 mg/L TDZ.We also observed that TDZ showed an inhibitory effect on the plant height,root number and root length of regenerated plants,and the inhibitory effect was strengthened with increasing TDZ concentrations.IAA had no obvious effect on the growth of regenerated plants in prence of TDZ.Overall,combination of 0.1 mg/L TDZ and 0.1～0.5 mg/L IAA showed best results for bud proliferation,growth of regenerated plants.The corm induction was highest with 0.1 mg/L TDZ,and it significantly decreased when TDZ concentration higher than 0.2 mg/L.(3)Among the genes involved in endogenous IAA biosynthesis,metabolism and action,and genes involved in starch biosynthesis and metabolism,most of them have high similarity of amino acid sequence and close relationship with monocots Ananas comosus,Elaeis guineensis,Oryza.sativa,Triticum aestivum,Zea mays.