NO_2^-对水稻生长发育的影响

GROWTH AND DEVELOPMENT OF RICE SEEDLINGS AS INFLUENCED BY NO_2^-

在水培条件下,当NO_2^-浓度低于60mg/kg时,秧苗干重、鲜重及含N量都随NO_2^-浓度升高而增加;当NO_2^-浓度超过60mg/kg,干重、鲜重及含N量则随浓度升高而降低,但这种降低可因Fe^(++)的存在而减弱,在相同施N量下,秧苗干重、苗高、分蘖数和含N量也会因为NO_2^-的施用而下降。NO_2^-显著影响根系呼吸强度和秧苗含水量,根系吸氧量及秧苗含水量随NO_2^-浓度升高而减少。NO_2^-提高亚硝酸还原酶活性,而对硝酸还原酶活性的影响较小。

Rice seedlings were cultured in a deionized water solution to investigate the effects of NO_2^-on their growth and development. Fresh wight, dry weighy and N content of the seedlings increased with NO_2^-concentrations in the range of 0—60 ppm. The three parameters decreased with NO_2^- in the range of 60—100 ppm, but the decrease was slowed down in the presence of Fe^(++). Given equal N rates, dry weight, plant height, tiller number and N content of the seedlings were lower with NO_2^- as N source than with NH_4^+-N or NO_3^--N. Respiratory intensity and water content of the seedlings declined with the rise in NO_2^- concentration. NO_2(56 ppm) raised nitrite reductase activity, but had little effect on nitrate reductase activity.