Effects of Exogenous Melatonin on Photosynthetic Characteristics of Lettuce Seedlings under NaCl Stress

Abstract

Abstract.A pot experiment was conducted to study the effects of spraying melatonin(MT) on photosynthesis of lettuce seedlings under NaCl stress. The results showed that net photosynthetic rate(Pn), stomatal conductance(Gs), light use efficiency (LUE)and transpiration rate (Tr) were improved, especially when the concentration of melatonin was 100μmol·L -1 , increased by 31.85%(P<0.05), 55.82% ( P <0.05), 31.85% ( P <0.05) and 48.64% ( P <0.05) compared withcontrol,respectively.Therefore, exogenous MT could efficiently increase resistance oflettuce seedlings toNaCl stress, and theMT concentration of 100 μmol·L -1 was the best.

Exogenous melatonin enhances salt stress tolerance in tomato seedlings

“…The protective role of melatonin pretreatment has been proved under salinity in many plants. Many studies reported that photosynthesis and chlorophyll content were improved in tomato seedlings (Zhou et al 2016, Yin et al 2019, watermelon seedling (Li et al 2017a), lettuce seedling (Yan et al 2016), and cucumber seedling (Wang et al 2016a, Zhang et al 2020. Under drought, it has been reported by Liu et al (2015a) that antioxidant capacity and photosynthesis of tomato seedlings are enhanced by melatonin treatment.…”

Comparative Analysis of Italian Lettuce (Lactuca sativa L. var. ramose) Transcriptome Profiles Reveals the Molecular Mechanism on Exogenous Melatonin Preventing Cadmium Toxicity

“…Under Cd stress, the fresh and dry matter yield of leaves and roots was significantly reduced in lettuce, and both roots and leaves show an increase in H 2 O 2 content while the superoxide dismutase SOD was stimulated [ 13 , 38 , 39 ]. After melatonin treatment, the photosynthetic rate, stomatal conductance, and light-use efficiency were more improved than those of the control [ 40 ]. Additionally, exogenous melatonin could eliminate the excess nitrate stress in lettuce tissues and enhance the photosynthesis [ 41 ].…”