光强对盆栽芒萁光响应过程与抗氧化酶系统的影响

为研究不同光强处理下盆栽芒萁Dicranopteris dichotoma光合生理参数与抗氧化酶系统的响应特征，以盆栽芒萁为研究材料，通过覆盖不同层数遮阳网模拟3种光环境，并以全光处理为对照，测定光合-光响应进程中的气体交换参数、抗氧化酶活性以及可溶性蛋白质和丙二醛（MDA）等参数。结果表明:①随遮阳程度减弱，盆栽芒萁的最大净光合速率、光补偿点、光饱和点、暗呼吸速率和表观量子效率均呈先增加后下降的变化特征；净光合速率以13.00%全光处理下最大，除对照外，4.75%全光处理下的光饱和点升高，光补偿点和表观量子效率最低。②4个光梯度中，35.96%全光处理是气孔因素向非气孔限制因素转变的转折点，而盆栽芒萁的净光合速率、蒸腾速率、气孔导度均在13.00%全光处理时达最大值。③盆栽芒萁的可溶性蛋白质为722.27 μg·g-1，MDA为7.74 mmol·g-1，均在全光下达最大值，并与抗氧化酶协同作用以维持盆栽芒萁幼苗的正常生长。因此，盆栽芒萁对光的适应可通过光合生理参数、抗氧化酶活性、可溶性蛋白质和MDA的变化获得调节。

Photosynthetic characteristics and enzymatic antioxidant system of Dicranopteris dichotoma with differing light intensity

To study the response characteristics of photosynthetic parameters and the antioxidant enzyme system in Dicranopteris dichotoma, different layers of shade netting in a greenhouse were simulated for four kinds of light environment (shade treatments of 0%, 4.75%, 13.00%, and 35.96% of the full light treatment or zero, one, two, and three layers of netting) to measure the effects of the photosynthetic response process, gas-exchange, antioxidant enzyme activity, soluble protein content, and malondialdehyde (MDA) content of potted D. dichotoma. Results were as follows:(1) when the light intensity increased the maximum net photosynthetic rate, light compensation point, light saturation point, dark respiration rate, and apparent quantum efficiency increased first and then decreased. The net photosynthetic rate was highest at the 13.00% of full light treatment. Compared to the control group, the light saturation point, light compensation point, and apparent quantum efficiency with 4.75% of the full light treatment were the lowest. (2) For the four light gradients, the 35.96% of full light treatment was a turning point from stomatal factors to non-stomatal limiting factors; whereas, the net photosynthetic rate, transpiration rate, stomatal conductance, and stomatal limitation value with the 13.00% of full light treatment was maximum. (3) The soluble protein content was 722.27 μg·g-1, and the MDA content was 7.74 mmol·g-1 with both reaching maximum in full sunlight; moreover, these two parameters synergized well with antioxidant enzymes to keep growth normal. Thus, resistance to light stress with potted D. dichotoma could be enhanced by adjusting the content of soluble protein and MDA, the activities of antioxidant enzymes, and physiological parameters with different light environments.