低镁胁迫对不同品种柠檬生长、光合特性和镁元素吸收的影响

Effects of low magnesium stress on plant growth,photosynthetic characteristics and magnesium content of different lemon varieties

我国南方地区是柠檬的主产区,柠檬缺镁现象十分明显,不同品种耐缺镁能力有很大差异,通过对比不同柠檬品种对低镁胁迫响应的差异,筛选出耐缺镁的品种,为柠檬种植的品种布局提供理论依据。以费米耐劳、云柠一号尤力克、塔西提莱檬3个主栽的柠檬品种为材料,以沙培的方式在镁缺乏(0 mg/L)、镁不足(6 mg/L)、镁正常(24 mg/L)3个浓度下进行培养,比较研究植株长势、光合特性和镁元素的吸收的差异,初步解析不同柠檬品种对低镁胁迫的生理响应。结果表明,在镁胁迫时植株的生长受到抑制,不同柠檬品种响应有所差异,在供镁浓度为0 mg/L时,费米耐劳和云柠一号老叶呈倒V字型黄化,塔西提则无此现象。低镁胁迫时植株的光合作用受到抑制,费米耐劳、云柠一号、塔西提叶片中的叶绿素含量分别下降16.81%、18.01%、13.95%;镁胁迫下蒸腾速率、净光合速率、气孔导度分别下降9.92%~58.96%、10.70%~37.97%、9.80%~31.71%;不同品种柠檬光合指标下降的幅度从小到大为:塔西提、云柠一号、费米耐劳。镁胁迫下不同柠檬品种各部位的镁含量都减少,费米耐劳、云柠一号、塔西提分别减少22.66%、28.34%、24.32%。综合来看,各品种表现为塔西提最耐镁缺乏,云柠一号和费米耐劳不耐镁缺乏,在镁缺乏地区应根据不同品种合理补充镁肥。

The southern China is the main producing area of lemon and the deficiency of magnesium in lemon is serious.The resistance to magnesium deficiency of various varieties was different.The variety most resistant to magnesium deficiency was screened out through the comparison of responses of various lemon varieties to low magnesium deficiency.It provided a theoretical basis for the variety layout of lemon planting.In this study,Femminello,No.1 Yunning Eureka and Tahiti lemon,which are the three main varieties of lemons in industrial cultivation,were used as materials and cultivated in sands with three concentration treatments including magnesium deficiency(0 g/L),magnesium insufficiency(6 g/L),and magnesium normal(24 g/L).The physiological responses of various lemon varieties to low magnesium deficiency were preliminarily revealed through the comparison of plant growth,photosynthetic characteristics and magnesium content.The results showed that plant growth was inhibited under magnesium stress,however,the response of various varieties was different.When the magnesium was 0 mg/L,the old leaves of Ferminellao and No.1Yunning showed inverted V-shaped yellowing,but Tahiti did not.Photosynthesis of plants was inhibited under low magnesium stress.Contents of leaf chlorophyll decreased by 16.81%,18.01%,13.95%,respectively,in Femminello,No.1 Yunning Eureka,Tahiti.The transpiration rate,net photosynthetic rate and stomatal conductance of lemons decreased by 9.92%~58.96%,10.70%~37.97%,9.80%~31.71%.The decreasing amplitude depended on varieties,the photosynthetic physiology order from small to large was Tahiti,No.1 Yunning Eureka,Femminello.Magnesium content in different parts of different lemon varieties all decreased under low magnesium stress,and the reduction of Femminello,No.1 Yunning Eureka,Tahiti was 22.66%,28.34%,24.32%,respectively.Based on the above indicators,Tahiti was the most resistant variety to low magnesium deficiency,No.1 Yunning Eureka and Femminello was not resistant to low magnesium deficiency.Magnesium fertilizer should be supplemented according to different varieties in magnesium deficiency areas.