不同Zn2+活度对水稻根和叶生长生理特性的影响

在营养液水培条件下，研究了不同Zn2+活度((pZn2+9.7, pZn2+11.0和pZn2+> 11.5 )对水稻根叶的生长发育和若干生理特性的影响。结果表明：低Zn2+活度下，对水稻秧苗的出叶速度减慢，但不同基因型间存在明显差异，极度缺锌(pZn2+>11.5)时，敏感品种只生长3.5叶，而耐低锌品种生长4.5叶左右；轻度缺锌或缺锌初期叶绿素含量上升和

Fffect of Different Zn~(2 ) Activities on the Growth and Some Physiological Characteristics of Leaf and Root among Rice Genotypes

Six rice genotypes with different Zn efficiency were cultivated at different Zn2 activities (pZn2 9.7, pZn2 11. 0 and pZn2 >11.5) in nutrition solution. Effect of different Zn2 activities on the growth and some physiological characteristics of leaf and root of rice were studied. It was found that the ability of rice tolerance to Zn deficiency significantly differed among the rice genotypes. The growth rate of leaf significantly decreased at low Zn2 activity, and there were obvious differences among the genotypes. The Zn-inefficient rece genotypes could only grow up to 3. 5 leaves and Zn-efficient rice genotypes could grow to 4. 5 leaves at pZn2 >11.5. The chlorophyll content slightly increased at pZn2 from 9. 7 to 11. 0, but decreased at pZn2 >11. 5. Root oxidizing power (ROP) considerably increased at severe Zn deficiency (pZn2 >11.5). At seedling age of 39, it was interesting that ROP decreased about one-fold for the Zn-efficient genotypes but increased markedly for Zn-inefficient genotypes when plants were grown at pZn2 11.0. Dry matter (DM) accumulation of roots increased when Zn2 activities were lower than pZn2 11.5 for all the genotypes tested. However, Shoot DM of Zn-efficient rice genotypes significantly decreased but their root DM significantly increased when pZn2 decreased from 9.7 to 11.0. Shoot DM of Zn-inefficient rice genotypes significantly decreased and no significant increase in root DM were observed when pZn2 decreased from 9. 7 to 11. 0. Therefore, the DM ofwhole plant for Zn-efficient rice genotypes had not significantly decreased while that for Zn-inef-ficient rice genotypes had significantly decreased at relatively low Zn2 activities. At pZn2 > 11. 5, the DM of all rice genotypes significantly decreased, especially for Zn-inefficient rice genotypes. It could be concluded that the growth rate of rice leaf and DM accumulation of shoot at relative low Zn activity could be used as the index for identifying Zn-efficient rice genotypes. Further, pZn2 11.0 might be a critical Zn2 activity to screen Zn-efficient rice genotypes.