摘要
【目的】探究红核桃与绿核桃光合特性的差别,为红核桃资源的开发利用和新品种培育提供参考。【方法】以红核桃和绿核桃(品种为‘中林1号’)为试材,通过切片观察和pH示差法对光合色素进行定性和定量的比较,并采用LI-6400 XT便携式光合测定仪对自然光照下的净光合速率、气孔导度、胞间CO2浓度、蒸腾速率、水分利用率及空气相对湿度等指标进行测定分析。【结果】两种核桃叶片的解剖构造无差异,但切片能够观察到红核桃中红褐色的花青苷的存在,pH示差法显示绿核桃总叶绿素含量以及类胡萝卜素含量高于红核桃,红核桃花青苷含量高于绿核桃;全天净光合速率为绿核桃大于红核桃,绿核桃的净光合速率为明显的双峰曲线,在12:00出现"光合午休"现象,红核桃的净光合速率为不规则型,在14:00出现了"光合午休"现象。绿核桃和红核桃气孔导度、胞间CO2浓度、蒸腾速率、水分利用率等差异不大。【结论】红核桃和绿核桃相比叶绿素含量较低,花青苷含量高,净光合速率较低。
【Objective】In this research,red-and green-leafed walnuts(’Zhonglin 1’)were used as the materials for comparing the photosynthetic parameters between two types of walnuts under field conditions.The purpose of the study was to explore the differences in photosynthetic characteristics between red-and green-leafed walnuts,so as to provide a reference for the development and utilization of redleafed walnut resource.Therefore,in this experiment,the diurnal variation of photosynthetic parameters and the difference in photosynthetic pigment contents were studied.【Methods】4-year-old red-and green-leafed walnut trees were grown at a space of 2 m×3 m in north-south row and cultivated with conventional management.Total chlorophyll,carotenoid and anthocyanin contents in leaves during fruit setting period(April 25,2019)and seed enrichment period(June 27,2019)were determined using UV-visible spectrophotometer(L5,Shanghai).Determination of photosynthetic parameters was carried out during the walnut fruit growth period(July 6,2019).Photosynthetic parameters were determined under natural conditions with a portable photosynthetic analyzer(Li-6400 XT,USA).The healthy and consistent leaves from the middle compound leaves on the branches were selected as the samples.The photosynthetic parameters were measured at two hours interval from 6:00 to 18:00,including net photosynthetic rate(Pn,μmol·m^-2·s^-1),transpiration rate(Tr,mmol·m^-2·s^-1),intercellular CO2 concentration(Ci,μmol·mol-1),stomatal conductance(Gs,mol·m^-2·s^-1),atmosphere relative humidity(RH,%)and water use efficiency(WUE,mmol·mol-1).All the test data were analyzed using Microsoft Excel 2010 and Origin pro 8.【Results】The photosynthetic activity of red-leafed walnut was lower than that of green-leafed one.The diurnal changes of net photosynthetic rate of green-leafed walnut showed an obvious"bimodal curve"and the"photosynthetic noon break"appeared at 12:00.The diurnal variation of net photosynthetic rate of red-leafed walnut was irregular with a clear"photosynthetic noon break"around 14 o’clock.The Pmax in green-leafed walnut and red-leafed walnut were 15.3 and 12.67μmol·m-2·s-1,respectively.The GSin both leaves exhibited a bimodal curve and kept consistent with changes in net photosynthetic rate.The Ciin both leaves had the same trend.They all decreased first,then rised slowly,and then decreased again after 14:00.Because the Gsof red-leafed walnut was lower than that of green-leafed walnut,the Tr was lower than that of green-leafed walnut.The Trin both leaves still showed a bimodal curve,and the highest peak appeared at 14:00.The total chlorophyll and carotenoid contents in leaves of green-leafed walnut were higher than those of red-leafed walnut,while the contents of anthocyanin in leaves of the red-leafed walnut were higher than those of green-leafed walnut during fruit setting period,and the content of anthocyanins of red-leafed walnut decreased rapidly during fruit growth period,but still higher than those of green-leafed walnuts.Many studies have shown that the photosynthetic efficiency of colorful plants is lower than green-leafed plants.However,the photosynthetic capacity of some colorful plants did not decreased,but instead was higher than green-leafed tree species.The photosynthetic efficiency of red-leafed walnut was lower than that of green-leafed walnut in this test.This may be due to the presence of anthocyanins.It is possible that anthocyanins absorbed and dissipated a part of the light energy,resulting in a decrease in the light energy available for photosynthesis.【Conclusion】The photosynthetic capacity of red-leafed walnut was weaker than that of green-leafed walnut,which may be related to the presence of anthocyanins in the leaves of red-leafed walnut.When growing red-leafed walnuts,we should create conditions conducive to photosynthesis as much as possible,such as reasonable pruning,excellent ventilation and light transmission;appropriate irrigation in summer to increase the humidity in walnut orchards,reducing temperature and transpiration,shortening the time of photosynthetic noon-break,and improving photosynthetic levels.
作者
杨莹
王磊
刘永辉
吴文江
孟海军
赵伟
李琳
吴国良
YANG Ying;WANG Lei;LIU Yonghui;WU Wenjiang;MENG Haijun;ZHAO Wei;LI Lin;WU Guoliang(College of Horticultural Science,Henan Agricultural University/Henan Key Laboratory of Fruit and Cucurbit Biology,Zhengzhou 450002,Henan,China;College of Food Science and Technology,Henan Agricultural University,Zhengzhou 450002,Henan,China)
出处
《果树学报》
CAS
CSCD
北大核心
2020年第8期1175-1183,共9页
Journal of Fruit Science
基金
河南省二〇一九年科技发展计划(科技攻关)(192102110041)。
关键词
红核桃
绿核桃
光合
花青苷
Red-leafed walnut
Green-leafed walnut
Photosynthetic
Anthocyanins
