Improving Leaf Photosynthetic Performance of Apple through a Novel Root-Zone Irrigation in the Loess Plateau

As freshwater becomes an increasingly scarce and expensive natural resource, novel water-saving irrigation methods for dwarfing apple orchards are needed in the Loess Plateau. However, studies lacking on effects of root-zone technology leaf-level photosynthesis, which directly determines yield survival ability trees. In this study, leaf gas characteristics water status five-year-old trees Plateau China were monitored during 2016–2017 growing seasons under storage pit (WSPI) surface (SI) treatments. Under WSPI, potential (?m), net photosynthesis rate (Pn), stomatal conductance (gs), chlorophyll content (Chl) significantly higher than those SI (by 12.21–28.36%), while non-photochemical quenching, superoxide dismutase, sucrose lower. Compared with SI, WSPI improved by 25.4% 26.7% 2016 2017, respectively. increased photosystem II (PSII) activity increasing fluorescence features (the quantum PSII (Fv/Fm), actual (?II), photochemical quenching (qP), electron transport (ETR)). Principal component analysis showed that ?m, Chl, (qP, ?II, ETR), Pn, gs could represent photosynthetic difference between Results indicated improve its through enhancing performance, is effective method