Photosynthetic responses of Monarch birch seedlings to different timing of free air ozone fumigation
Photosynthetic responses of Monarch birch seedlings to different timing of free air ozone fumigation
复制标题
帝王桦幼苗对不同时间自由空气臭氧熏蒸的光合反应
DOI：
10.1007/s10265-013-0622-y
复制
发表时间：
2014
影响因子：
2.8
通讯作者：
T
中科院分区：
文献类型：
--
作者：
Watanabe;M.;Hoshika;Y. and Koike;T
为了研究不同时期的臭氧（O3）熏蒸对帝王桦（Betula maximowicziana）叶片光合作用的影响，我们在白天对帝王桦幼苗进行了浓度为60 nmol mol−1的自由空气O3熏蒸。植物在生长季节的早期、晚期或两个时期都暴露于O3。 7 月和 8 月的光饱和净光合速率 (Asat) 因 O3 暴露而降低最大羧化速率 (Vc,max)。另一方面，在 9 月初，尽管 Vc,max 减少，但由于气孔导度的增加而抵消 O3 的影响，Asat 并未减少。通过实验，成熟叶片和成熟叶片对O3的敏感性没有差异。我们分析了Asat、Vc、max与累积气孔O3通量（AFst）之间的关系。而Vc、max随着AFst的增加而降低，但由于气孔导度对O3的响应受季节影响，Asat与AFst的相关性较弱。我们得出帝王桦对 O3 暴露的光合反应随季节变化的结论。这是由于气孔对 O3 的反应不稳定，而不是由于叶绿体生化同化能力的反应。
To study the effects of different periods of ozone (O3) fumigation on photosynthesis in leaves of the Monarch birch (Betula maximowicziana), we undertook free air O3fumigation to Monarch birch seedlings at a concentration of 60 nmol mol−1during daytime. Plants were exposed to O3at early, late or both periods in the growing season. The light-saturated net photosynthetic rate (Asat) in July and August was reduced by O3exposure through a reduction in the maximum rate of carboxylation (Vc,max). In early September, on the other hand, despite a reduction inVc,max,Asatwas not reduced by O3due to a counteracting increase in the stomatal conductance. Through the experiment, there was no difference in sensitivity to O3between maturing and matured leaves. We analyzed the relationship betweenAsat,Vc,maxand accumulated stomatal O3flux (AFst). WhereasVc,maxdecreased with increasing AFst, the correlation betweenAsatand AFstwas weak because the response of stomatal conductance to O3was affected by season. We conclude photosynthetic response of Monarch birch to O3exposure changes with season. This is due to the inconstant stomatal response to O3but not due to the respose of biochemical assimilation capacity in chloroplasts.