Effects of Saline-Fresh Water Rotation Irrigation on Photosynthetic Characteristics and Leaf Ultrastructure of Tomato Plants in Greenhouse
[Objective]Revealing the mechanisms of saline-fresh water rotation irrigation that affected the leaf ultrastructure and photosynthetic characteristics of tomato plants was benefit to optimize the strategy of saline water irrigation of greenhouse tomatoes.[Method]In this paper,the local conventional tomato variety"Mingzhu"was used as the material to carry out a two-year trial of saline and fresh water irrigation in greenhouses in the southern Xinjiang region from 2022 to 2023.The four treatments consisted of rotation irrigation with four times saline-fresh water(W1),rotation irrigation with two times saline water and two times fresh water(W2),rotation irrigation with two times fresh water,four times saline water,and two times fresh water(W3),and freshwater irrigation as a control(CK).The three rotation patterns had the same amount of saline water and fresh water.The effects of saline and alkaline stress produced by saline and freshwater rotational irrigation on the ultrastructure,chlorophyll content,stomatal characteristics,gas exchange parameters,and yield of facility tomato leaves were mainly investigated.[Result]The results indicated that the saline-alkali stress introduced by saline water significantly reduced the gas exchange parameters of tomato leaves and water use efficiency at the leaf scale,and both stomatal and non-stomatal factors played a key role in limiting leaf gas exchange.Tomato leaves not only adapted quickly to salinity stress by reducing individual stomatal openings,but also improved gas exchange efficiency by regulating stomatal density and stomatal shape through long-term stomatai differentiation and development.Compared with the CK treatment,the stomatal density of the leaves under W1,W2,and W3 treatments increased by 22.8％,43.0％and 13.8％,respectively,and the stomatal width was reduced by 54.6％,77.8％,and 13.7％,respectively;under the influence of soil salinity stress,compared with CK treatment,the chloroplast granular lamellae structure was disrupted in tomato leaves under Wl and W2.Compared with CK,W1 and W2 decreased leaf chlorophyll content by 6.2％and 11.8％,net photosynthetic rate by 16.3％and 26.2％,and yield by 45.3％and 52.5％,and the maximum leaf area index was 20.8％and 27.5％lower than that in the same period of CK treatment,respectively.In contrast,W3 presented a relatively intact mesophyll cell structure and relatively high chlorophyll content and photosynthetic efficiency,W3 only increased the average single fruit weight by 6.5％,fruit diameter by 6.0％and the yield by 0.7％,with no significant differences compared with CK.[Conclusion]By comprehensive analysis of physiological changes and yield of tomato,irrigation of saline water in the flowering and fruiting period-fruit expansion period of tomato,the other reproductive stages of freshwater irrigation,to mitigate the adverse effects of saline water irrigation on the growth of tomato,W3 treatment was recommended as a facility in the southern Xinjiang region of the synergistic use of saline-fresh water irrigation of tomato.
tomato(Solanum lycopersicum L.)rotational irrigation with saline and fresh waterultrastructurephotosynthesisyield
万方数据
