温室栽培西瓜座果期冠层光合作用日变化研究

在兰州春季塑料日光温室条件下研究了‘宝冠’和‘新金兰’两个品种西瓜(Citrullus lantus(Thunb．) Mansf．)冠层光合作用日变化特性。结果表明,日光温室两个西瓜品种间冠层光照分布和单叶光合作用日变化模式存在明显的差异,冠层光照条件影响各叶层的光合强度及其日变化态势。两品种冠层整体光合速率日动态呈单峰型,‘宝冠’的光合生产力高于‘新金兰’。‘宝冠’西瓜单叶光合速率较高,高效光合时间较长,且表现出午休特征。‘新金兰’西瓜单叶光合速率低,高效光合维持时间较短,未表现出明显午休特征。‘宝冠’光合作用的瞬时水分效率 (WUE)高于‘新金兰’,两品种上午的WUE高于下午,上层叶的WUE高于下层叶。

Diurnal Photosynthetic Change in the Canopy of Greenhouse Watermelon at the Fruit-setting Stage

The diurnal photosynthetic changes in the canopies of two watermelon varieties Citrullus lantus (Thunb.)Mansf.],'Baoguan' and 'Xinjinlan' ,were studied in greenhouse in Lanzhou in spring. The results showed that the two varieties significantly differed in canopy light distribution and diurnal photosynthetic pattern in individual leaves and the canopy light distribution affected the photosynthetic rates in the canopies of the two varieties varied in a single-peak curve and the photosynthetic rate of 'Baoguan' was higher than that of 'Xinjinlan'. In 'Baoguan' ,the photosynthetic rates of individual leaves were higher,the high-efficiency photosynthesis lasted longer and midday depression occurred. In 'Xinjinlan' ,the photosynthetic rates in individual leaves were lower,the high-efficiency photosynthesis lasted shorter and obvious midday depression took place. The transient water use efficiency in the photosynthesis of 'Baoguan' was higher than that of 'Xinjinlan' and the water use efficiencies of the two varieties were higher in the morning than in the afternoon and higher in their upper leaves than in their lower leaves.