两种番茄对缺镁胁迫的光合响应

Photosynthetic Responses of Two Tomato Cultivars to Magnesium Deficiency

镁是植物必需的大量元素之一,具有重要的生理功能。缺镁严重影响作物的生长,降低产量和品质。番茄是最重要的蔬菜作物之一,受土壤pH值降低、强降雨淋溶以及氮磷钾肥量大施用的影响,缺镁已成为番茄生产中的一种常见现象。本研究以2个番茄品种(‘HTS-069’和‘HTS-056’)为材料,从叶片光合的角度研究缺镁胁迫对番茄的影响。结果表明,缺镁降低了番茄的净光合速率、气孔导度和蒸腾速率。且不同品种对缺镁也有不同的响应,缺镁降低了‘HTS-056’的光合能力,加速了叶片的光损伤,抑制了PSⅡ系统的开放及PSⅡ系统的电子传递。在缺镁条件下,‘HTS-069’叶绿素荧光没有显著变化。以上结果表明,在缺镁条件下,不同番茄材料光能转化效率及光保护能力具有显著差异,不同番茄耐缺镁能力不同,叶绿素荧光可作为番茄耐缺镁选择的重要依据。本研究通过比较缺镁处理对不同番茄材料光合及叶绿素荧光的影响,为筛选镁高效利用番茄材料提供理论基础。

Magnesium(Mg) is one of the essential elements in plants and Mg deficiency can affect crop growth,yield and product quality.Tomato(Solanum lycopersicum) is one of the most important vegetables in China.Due to the decreasing soil pH value,heavy rain leaching and excessive nitrogen,phosphorus and potassium application,Mg deficiency is commonly observed in tomato field.This study used two tomato genotypes(’HTS-069’ and’HTS-056’) to detect the effects of Mg deficiency on photosynthesis.The results showed that Mg deficiency reduced photosynthetic rate,transpiration rate and stomatal conductance of tomato seedlings.In ’HTS-056’,photosynthesis were severely reduced,leaves were damaged and the reaction center of PSⅡ were closed with Mg deficiency.While in ’HTS-069’,chlorophyll fluorescence were not significantly changed when compared with that of control.These results indicated that chlorophyll fluorescence might be an important index to screen Mg deficiency tolerant tomato genotypes.In addition,the photosynthetic analysis may also provide a tool for screening tomato elite genotypes.