不同氮素水平下玉米及高粱幼苗营养的研究

本试验结果表明:1、玉米在第2叶、高梁在第1叶期便对外源养分有较大的吸收,且随供氮水平提高,吸氮增加,吸磷、钾在2N范围内也增加。2、外源养分及适当的供氮水平明显地提高了二作物1叶后的根系生长和干物质积累速度。3、供外源养分时,玉米离乳叶龄增大,高粱3叶后不再消耗胚乳养分,故认为其自养生长的建立不应完全以胚乳物质的消耗来衡量。4、二作物幼苗期的供氮浓度以40—80ppm为佳,高氮(120ppm)是不利的。且应保证1叶期左右有外源养分的供应。

STUDY ON THE SEEDLING NUTRITION OF MAIZE AND SORGHUM AT VARIOUS NITROGEN LEVELS

By means of the sand culture, the growth, absorption of nitrogeu (N), phosphoru(P)and potassium (K), consumption of endosperm and the endosperm-exhaustion of maize and sorghum seedlings at various N levels were studied. The results are as follows: 1) Maize and sorghum seedlings absorbed much nutrients from culture medium respectively at the 2-and 1-leaf-stage, and the absorption of N was promoted by increasing N levels and that of P, K was also promoted by increasing N levels at 2N. 2) And because of the supplying of the exogenous untrients and the proper N concentration th development of the roots and the accumulation of the dry matter of the two erops'after the period of the 1-lear-stage were obviously improved, and the growth of the seedlings was doing well. 3) while supplying the exogenous nutrients, the matter of endosperm was no longer consumed after the 3-lear-stage in sorghum seedlings. So the ability to carry cut autotrophic nutrition is not measured only by the consumption of endosperm. 4) The optimum concentration of exogenous N for the seedlings was 40-80ppm, and the supplying of the exogenous nutrients was ensured at abcut 1-lear-stage peried. The high level N (120ppm) was unfavourable.