Effects of Different Submergence Stresses from Winter to Spring on the Growth of Mulberry Saplings and Trees

The effects of different submergence stresses from winter to spring on the growth of one and two-year old saplings of mulberry varieties Nongsang 14 and Qiangsang 1 were investigated.The result showed that,saplings completely submerged(CS)until the early leaf expanding period didn't sprout and died.Saplings submerged completely before the leaf expanding period sprouted more slowly with the increase of submergence time.When roots submerged(RS)or roots and half stem submerged(HS)for at most 90 days until 30days after leaf expanding,the saplings could sprout and grow.The submergence tolerance ability of Qiangsang 1 was a little stronger than Nongsang 14.And the submergence tolerance ability of two-year old saplings was a little stronger than one-year old ones.Spring leaf yield of 22 varieties submerged from winter to spring were also investigated.The results showed that,108 days submergence of root from winter to spring,15th Jan to 1st May,would affect the spring leaf yield to some extend,but had no significant affection on the survival and growth of mulberry trees.