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为探讨不同强度高温对南高丛蓝莓叶片气孔特征及其气体交换参数的影响,利用人工气候箱设置4个温度处理:对照(25℃)、轻度高温(30℃)、中度高温(35℃)和重度高温(40℃)对两年生南高丛蓝莓(Vaccinium corymbosum L.)幼苗(海岸、奥尼尔及蓝脊)进行为期90 d的光照培养实验。研究结果表明:高温增加海岸和蓝脊叶片的气孔密度,但对奥尼尔的气孔密度无影响。中度高温增大奥尼尔和蓝脊叶片气孔的长度、宽度和面积,但海岸的气孔长度比轻度高温减小23.5%(P<0.05)。高温使奥尼尔的气孔空间分布更加规则,而对海岸和蓝脊的影响不大。3个品种的叶片净光合反应速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)均随高温强度先升高后降低,但其最大值随品种发生变化。研究结果表明,南高丛蓝莓具有调整气孔结构特征和优化气孔空间分布格局提高其气体交换效率的功能,但在品种间存在较大的差异,最终导致气体交换参数对高温产生不同的响应,尤其表现在抵抗极端高温能力方面。结果有助于从叶片气孔特征变化角度深入理解不同高温强度对南高丛蓝莓气体交换产生影响的潜在机理,为蓝莓耐高温胁迫选育及引种栽培工作提供理论支持。
In order to explore the effects of different intensities and temperatures on the stomatal characteristics and gas exchange parameters of blueberry (Brassica napus L.) leaves, four temperature treatments were set up in the artificial climate chamber: control (25 ℃), mild high temperature (30 ℃) and moderate high temperature (Coastal, O’Neill and Blue Ridge) of two-year-old Southern blueberry (Vaccinium corymbosum L.) seedlings were irradiated with light at 40 ℃ for 90 days. The results show that high temperature increases the stomatal density of coast and blue ridge leaves, but has no effect on the stomatal density of O’Neill. Moderately high temperatures increased the stomatal length, width and area of the O’Neill and blue ridge leaves, but the stomatal length of the coast was reduced by 23.5% (P <0.05) compared with that of the mild high temperature. High temperatures make the distribution of O’Neill stomatal space more regular, but have little effect on the coast and the blue ridges. The net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of the three cultivars increased at first and then decreased with the increase of the high temperature, but their maxima varied with the varieties. The results showed that the blueberry of South GA had the functions of adjusting the stomatal structure and optimizing the spatial distribution pattern of stomatal space to improve the gas exchange efficiency. However, there was a big difference among the varieties, leading to different responses of gas exchange parameters to high temperature, especially Performance in the fight against extreme heat capacity. The results are helpful to understand the potential mechanism of different high temperature intensities on the gas exchange of blueberry blueberry from the perspective of leaf stomatal characteristics and provide theoretical support for the breeding and introduction and cultivation of blueberry under high temperature stress.