中图分类号：S792.95 文献标志码：A 文章编号：1673-923X（2025）07-0056-09

Characteristics of SPAD spatial distribution in Ginkgo biloba leaf layers and its relationship with nitrogen content

GAOYubo，ZHOUKai

（Co-Innovatieobletrtigtrity7）

Abstract：【Objective】Accurate，rapidand non-destructive diagnosisof Ginkgo bilobanitrogen status isconducivetonitrogen fertilizationregulationofGinkgobiloba，whichcanefectivelyimproveGinkgobilobagrowthanddevelopment，yieldandquality. 【Method】Thethree-yearoldbig Buddhafinger Ginkgo bilobaseedlings were taken from Baimabaseas theobject，andused SPAD chlorophyll metertostudytheleavesofdifferentlevelsofGinkgobiobasedingsatdifferentperiodsi2O.【Result】1）Withthe growthofGnkgoblobaseedlingswihinayear，theitrogencontentiteleavesgraduallcreasedhilethetrogenotet accumulatedintheplantodyraduallincreasedandthetwotrogenindexesshowedatrendofgadualstabilizationafteJune; 2）TherewasagoodcoelationrelatioshietweenPADindexesandrognnutrionalindexesofGnkgobilobasdigsbut it was notstable，and was greatlyaffectedbytheleavesatdifferenttimesoftheyearandatdiffrentheightlevels.Te moststable relationshipbetweenSPADvaluesandnitrogencontentwasfoundinthemiddleleavesofGnkgobilobasedingleaveswhichwas not limited bythe period，and the correlation coefficient ofdetermination reached the maximum in June （R²=0.56 Plt;0.001 ）;whereas it was moreustablewithitroenaccumulatio，andtecoelationcoefcintofetenationreachdthemaximumineptember （R²=0.60 ）;3） The correlation of the SPAD indexes with the leaf nitrogen content and nitrogen accumulation，the corelationbetweeSADandleafntrogncontentwasmorestableandtusmoresuitableasanefetivetechicalmeansfooen contentestimationinGinkgobilobaseedlings;4）Threesingle-periodmodelsandfourful-periodmodelswereestablishedbasedon therelationsipetweenL2ndLCndallofthcouldachevebeterrogencontentestimationefectsthoughprison and verification.Among them，the single-period models， the April model scriptstyle（R²=0.53 ，RMSE=0.18） and the June to September model （2 （R²=0.37 ，RMSE=0.28）are more reliable;the binaryquadratic regression model ofthe ful-period model has the highest accuracyof modelmeasurement R²=0.62 ，RMSE=0.26）.【Conclusion】The SPAD chlorophyll meter method can be used as a simple method for evaluatingthenitrogennutrionalstatusofGinkgobilobaseedlings，andcanprovideasimpleandfeasibletechnicalwaytomoitor nitrogen fertilisation in forest trees.

Keywords： Ginkgo biloba; SPAD;nitrogen estimation; chlorophyll meter

银杏Ginkgobiloba又名白果树、公孙树、鸭掌树，是源于第四纪冰川运动最古老的裸子植物，也是我国现存的活化石植物种类之一。银杏是一种耐酸、耐旱的喜光树种，可种植在山区、平原和滨海盐碱地，因此被亚洲和西方国家广泛引进。银杏是一种集医用、材用、观赏、生态保护和科研等多功能于一身的生态经济树种[。我国银杏资源丰富，银杏的药用价值和保健价值也随着对其生物学特性和成分的了解的深入而被不断开发[2]。

氮素作为银杏中必不可少的营养元素之一，可以促进林木的生长发育，还可以提高林木产量和品质[3]。氮供应不足会造成叶量稀少，叶绿素含量降低，生物量降低，林木产量及质量下降[4]。相反，过量使用氮会导致水和空气污染等环境问题[5]。氮素作为是银杏生长发育和提高产量所不能缺乏的元素，也是植物体内的氨基酸、蛋白质、核酸、磷脂、叶绿素酶、生物碱、多种苷和维生素合成的主要成分。适宜水平的氮供应可有效促进银杏叶片的生长和黄酮积累，提高银杏的光合效能。

因此，协调植物对氮素营养的需求平衡是银杏管护的一项重要内容。而林木氮肥的精确管控，需要对植株特别是叶片氮营养状况的快速准确诊断和评价。目前常用的现代林木氮素营养诊断技术主要包括外观诊断、化学诊断、机器诊断 [-]。随着相关领域科学技术的进步，许多学者研究了快速、无损、精确的氮素诊断技术，叶绿素仪方法、遥感技术和数字图像技术被发明并广泛应用[9-11]。……