摘要
针对中国现有设施番茄生产中氮肥施用量过高,利用率低,环境污染严重等问题,该研究面向设施番茄精量施肥需求,提出一种基于叶绿素荧光技术的设施番茄生长氮素浓度适宜区间获取方法。该研究利用不同氮浓度水培液进行番茄栽培,获取叶片荧光参数和干物质等生理指标,采用最大互信息系数值(Maximum Information Coefficient,MIC)筛选叶绿素荧光参数,确定最适的荧光参数进行水培液氮调控研究目的是区间确定。结果表明,叶绿素荧光参数F_(v)/F_(o)(光系统潜在活性)的整体表现效果较优。以F_(v)/F_(o)的响应曲线提出基于U弦长曲率特征点为分界点的适宜氮素浓度区间获取技术。采用此方法的番茄生长的适宜氮素浓度区间为7.2~9.8 mmol/L,同时干物质等生理指标都保持在较高水平,变异系数最小。与日本园试营养液对照组相比,番茄干质量平均提高33.8%,叶片磷浓度平均提高10.2%,叶片钾浓度平均提高11.3%,叶片氮浓度平均降低0.8%,而氮肥用量减少了51.4%。因此,基于U弦长曲率特征点的方法是确定番茄施氮目标区间调控有效的技术。
Artificial nitrogen fertilizer has been one of the most essential supplements for plant growth.Nitrogen can be an indispensable element for chlorophyll synthesis of most crops.However,the high nitrogen application rate in tomato production has posed a serious threat to the nitrogen utilization rate and ecological environment in recent years.In this study,data acquisition was proposed to obtain a suitable range of nitrogen concentration for tomato growth using chlorophyll fluorescence under the requirements of precision fertilization.Seven test groups were set with the nitrogen concentration gradient(3.5,7.0,10.5,14.0,17.5,21.0,and 24.5 mmol/L),according to the nitrogen content in the formula of Japanese garden test nutrient solution(17.5 mmol/L).The contents of other elements were the same as the formula in the experiment.The parameters of chlorophyll fluorescence and dry matter were obtained for the leaves of tomatoes that were treated with seven nitrogen concentrations.A systematic analysis was made to determine the change of dry weight,leaf nitrogen,phosphorus,and potassium concentration with the nitrogen concentration.As such,the nitrogen concentration of the nutrient solution was between 7.0-10.5 mmol/L suitable for the tomato plant growth.A correlation analysis of chlorophyll fluorescence parameters was carried out for the appropriate nitrogen concentration range using the maximum mutual information coefficient.The results showed that there were the most correlated parameters of chlorophyll fluorescence with the nitrogen concentration,including ABS/RC(absorbed flux absorbed by reaction center),PIABS(Performance Index based on ABS),ET_(o)/RC(electron transport flux captured by reaction center),and F_(v)/F_(o) (Potential activity of photosystems),whose Maximum Information Coefficient(MIC)values were all greater than 0.4.The F_(v)/F_(o) was found to be the most suitable chlorophyll fluorescence parameter in the proper nitrogen concentration range for plant growth.The response curve of F_(v)/F_(o) to nitrogen concentration was obtained by the polynomial fitting the discrete points of Fv/Fo response to nitrogen concentration.The curvature curve was calculated using the u-chord curvature of the curve,and the point at which the curvature began to increase was taken as the curvature characteristic point.The curvature characteristic point and the maximum point were used as the lower limit and upper limit for the regulation interval of nitrogen concentration.The suitable nitrogen concentration range was 7.2-9.8 mmol/L for tomato growth.In this case,the dry matter and physiological amounts remained at a high level,and the coefficient of variation was the lowest,indicating that there was little effect of nitrogen concentration on the tomato growth.Specifically,the tomato dry weight,P and K concentration in the leaves increased by 33.8%,10.2%,and 11.3%on average,respectively,the N concentration in the leaves decreased by 0.8%on average,and the nitrogen application decreased by 51.4%,compared with Japan garden test nutrient solution treatment.There was also a higher plant dry weight,as well as the leaf N,P,and K contents,indicating balanced nutrient absorption.Consequently,a reasonable and accurate interval of nitrogen concentration can be achieved for crop growth.This finding can provide a theoretical basis for the accurate regulation of nitrogen application rate,further realizing the long-term monitoring of leaves without destructive physical and chemical testing.
作者
袁凯凯
卢苗
李慧敏
陈丹艳
张明科
胡瑾
Yuan Kaikai;Lu Miao;Li Huimin;Chen Danyan;Zhang Mingke;Hu Jin(College of Mechanical and Electronic Engineering,Northwest A&F University,Yangling 712100,China;Key Laboratory for Agricultural Internet of Things,Ministry of Agriculture and Rural Affairs,Yangling 712100,China;Shaanxi Key Laboratory of Agricultural Information Perception and Intelligent Service,Yangling 712100,China;College of Horticulture,Northwest A&F University,Yangling 712100,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2022年第11期188-196,共9页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家重点研发计划项目(2020YFD1100602)
国家大宗蔬菜产业技术体系岗位专家任务项目(CARS-23-C06)
陕西省重点研发计划项目(2021ZDLNY03-02)
中央高校基本科研业务费专项(2452020292)。
关键词
氮肥
叶绿素荧光
曲率
最大互信息系数
nitrogen fertilizer
chlorophyll fluorescence
curvature
the maximal information coefficient
作者简介
袁凯凯,研究方向为设施氮肥调控。Email:a18309292816@163.com;通信作者:胡瑾,副教授,博士,博士生导师,研究方向为设施光环境调控和智能信息处理。Email:hujin007@nwsuaf.edu.cn。
