滴灌不同土壤湿润比和施肥量对红豆杉光合特性和叶片结构的影响OA

[Objective]Taxus chinensis has important medicinal,ornamental and ecological value.Its seedling development is sensitive to soil water and nutrient availability.This study experimentally evaluated suitable wetted zone size under drip irrigation and fertilizer application rate for promoting seedling growth and improving water-and fertilizer-use efficiency.[Method]The experiment was conducted during the 2023 and 2024 growing seasons.It involved three irrigation treatments and three fertilization treatments.The irrigation treatments were defined by the ratio of wetted-zone area to total soil-profile area,which was set at 45%,60%,and 75%.Each irrigation treatment had three fertilizer application rates:0,3.0,and 4.2 kg/m3.During the experiment,photosynthetic traits,chlorophyll content and leaf anatomical characteristics were measured in each treatment.[Result]Both the wetted-zone size and fertilizer application rate significantly affected photosynthesis,chlorophyll content,and leaf anatomical development.When fertilizer application was the same,photosynthetic and chlorophyll traits showed a unimodal response to increasing wetted-zone size,initially increasing and then decreasing.When wetted-zone size was the same,fertilization significantly increased photosynthetic and chlorophyll traits compared to the unfertilized control.A moderate increase in fertilizer application rate further enhanced these responses.A wetted-zone coverage of 60%,combined with a fertilizer application rate of 4.2 kg/m3,resulted in the highest net photosynthetic rate,stomatal conductance,transpiration rate,chlorophyll content,midrib development,and palisade tissue thickness among all treatments.These results suggest that optimizing the size of the wetted zone is important for maximizing fertilizer-use efficiency.TOPSIS-based comprehensive evaluation indicated that the combination of a 60%of wetted-zone coverage and 4.2 kg/m3 fertilizer application was optimal for Taxus chinensis seedling growth.[Conclusion]Under the experimental conditions,maintaining a 60%wetted-zone coverage combined with a fertilizer application rate of 4.2 kg/m3 was optimal for promoting photosynthetic performance and leaf structural development in Taxus chinensisseedlings,while improving water-and fertilizer-use efficiency.