Kaur Narinder, Kaur Harpreet, Gupta Anil K
Department of Biochemistry and Chemistry, Punjab Agricultural University, Ludhiana 141 004, India.
Indian J Biochem Biophys. 2005 Oct;42(5):295-300.
Addition of exogenous sucrose and mannitol in the growth medium decreased the germination and growth of cowpea (Vigna unguiculata L. cv C-88) seedlings. The reduced seedling growth appeared to be due to the decreased acid invertase activity in growing parts of the seedlings. An exogenous supply of sucrose upregulated the sucrose phosphate synthase (SPS) activity in different parts of seedlings. Decreased amylase activity in cotyledons and the mobilization of starch from cotyledons to the growing axis was observed in the presence of exogenous sucrose and mannitol. High sucrose content observed in different tissues in the presence of exogenous sucrose and mannitol was possibly due to high SPS and low acid invertase activities and reduced conversion of sucrose to starch. It appears that exogenous sucrose acts mainly as an osmoticum, rather than a source of carbon for the growing seedlings.
在生长培养基中添加外源蔗糖和甘露醇会降低豇豆（Vigna unguiculata L. cv C - 88）幼苗的萌发和生长。幼苗生长减缓似乎是由于幼苗生长部位的酸性转化酶活性降低所致。外源供应蔗糖会上调幼苗不同部位的蔗糖磷酸合酶（SPS）活性。在存在外源蔗糖和甘露醇的情况下，观察到子叶中淀粉酶活性降低以及淀粉从子叶向生长轴的转运。在存在外源蔗糖和甘露醇的情况下，不同组织中观察到的高蔗糖含量可能是由于高SPS活性、低酸性转化酶活性以及蔗糖向淀粉转化减少所致。看来外源蔗糖主要起渗透剂的作用，而不是生长中幼苗的碳源。
