本文研究了大叶桃花心木(Swietenia macrophylla King)一年生幼苗在经过夜温处理后的光响应曲线和在饱和光强下的CO2反应曲线。结果表明:在大气CO2浓度下,叶片的最佳光合作用温度在25-31℃之间,而在饱和CO2浓度下为31-35℃。在25℃以下光合速率开始降低,主要是由于羧化效率的降低,而当温度超过31℃时,光合速率下降,是因为羧化效率的降低和呼吸速率的增加。CO2浓度对光
关注中国的经济发展,社会发展,信息化建设和工业化进程等这样一些决定着国家与民族命运的深远问题,无论是外国人还是我们自己人,都不能不把目光时时地投向中国的“经济之都”——上海。很大程度上,上海的发展态势决定着中国未来总的发展前景。 “软件地理”关注的焦点是区域信息化建设的问题。就此而言,上海无疑也是国内目前建设状况最好,信息化程度最高发展潜力最大的地区之一。在这个中国现代工业的摇篮里,我们也能够对“
某些植物种类在低温胁迫下积累甜菜碱,适应低温,提高对冰冻的忍受力.外施甜菜碱可以增强一些植物种类,包括天然积累甜菜碱和非积累甜菜碱植物的抗寒性.外施甜菜碱加上低温驯化处理比单独低温驯化处理更能提高植物的抗寒性.把编码甜菜碱生物合成酶的基因转到某些原来非积累甜菜碱植物上,也能产生、积累甜菜碱和提高抗寒性.
This paper proposes a new image restoration technique, in which the resulting regularized image approximates the optimal solution steadily. The affect of the regularization operator and parameter on t
The stability behaviour of unsaturated soil slopes under rainfall conditions is investigated via a parametric finite element analysis, which is a fully coupled flow and deformation approach linked to
The electrical conductivities (ECs) of suspensions containing 25 and 30 g kg-1 solids prepared from the electrodialyzed clay fraction (< 2μm in diameter) of latosol, yellow-brown soil, and black soil,
The increase of phosphorus concentration is a crucial factor causing the eutrophication of water body, while land use has an important impact on agricultural non-point sources (NPS) phosphorus dischar
Suspensions of a latosol with a clay concentration of 30 g kg-1 were prepared from electrodialyzed clay fractions,, less than 2 um in diameter, five nitrate solutions with a concentration of 1 X 10-4/