Riikonen Johanna, Mäenpää Maarit, Alavillamo Marjo, Silfver Tarja, Oksanen Elina
Department of Environmental Science, University of Kuopio, PO Box 1627, 70211, Kuopio, Finland.
Planta. 2009 Jul;230(2):419-27. doi: 10.1007/s00425-009-0957-8. Epub 2009 May 31.
We studied the effects of slightly elevated temperature (T), O(3) concentration (O(3)) and their combination (T + O(3)) on the antioxidant defense, gas exchange and total leaf area of Betula pendula saplings in field conditions. During the second year of the experiment, T enhanced the total leaf area, net photosynthesis (P (n)) and maximum capacity of carboxylation, redox state of ascorbate and total antioxidant capacity in the apoplast. O(3) did not affect the total leaf area, but P (n) was slightly and g (s) significantly reduced. The saplings responded to elevated O(3) level by closing the stomata and by developing leaves with a lower leaf area per mass, rather than by accumulating ascorbate in the apoplast. The effects of T and O(3) on total leaf area and P (n) were counteractive. Elevated O(3) reduced the saplings' ability to utilize the warmer growth environment by increasing the stomatal limitation for photosynthesis and by reducing the redox state of ascorbate in the apoplast in the combination treatment as compared to T alone.
我们在田间条件下研究了略高温度（T）、臭氧浓度（O₃）及其组合（T + O₃）对垂枝桦幼苗抗氧化防御、气体交换和总叶面积的影响。在实验的第二年，T增加了总叶面积、净光合速率（Pₙ）和羧化最大能力、质外体中抗坏血酸的氧化还原状态以及总抗氧化能力。O₃不影响总叶面积，但Pₙ略有降低，气孔导度（gₛ）显著降低。幼苗通过关闭气孔和发育单位质量叶面积较低的叶片来应对升高的O₃水平，而不是通过在质外体中积累抗坏血酸。T和O₃对总叶面积和Pₙ的影响具有拮抗作用。与单独的T处理相比，在组合处理中，升高的O₃通过增加光合作用的气孔限制和降低质外体中抗坏血酸的氧化还原状态，降低了幼苗利用温暖生长环境的能力。
