| The field experiment was carried out in the agronomy experimental station of Shandong Agricultural University from 2018 to 2019.To explore whether and how source-sink theory was involved in mediating peanut high yield formation,through the method of field measurement and laboratory analysis,the experiment was conducted using 13 major peanut cultivars in North China.Principal component analysis and cluster analysis were used to evaluate natural indicators for the characterization and classification of source-sink types such as leaf area(LA)per plant,number of flowers,and pod rate.According to the classification results of source and sink types,cultivars of different source and sink types are used as test materials,and the mechanism of source and sink differences in the formation of peanut yield and quality is studied by analyzing the differences in source and sink characteristics,assimilate accumulation and distribution differences and proteomics differences between cultivars.Aiming at the problem of the uncoordinated relationship between the source and sink of“more flowers but less pegs”and“more pods but less kernels”in production,which limits the increase of peanut yield,this paper discusses the regulatory effects of two control measures of ethephon on flower control and thick film control of needles on the formation of peanut source and sink.Provide a theoretical basis for the coordinated improvement of peanut yield and quality.The main research results are as follows:1 Classification of peanut cultivars source-bank types1.1 Indicators for measuring source-sink traits of peanutThe source and sink traits of peanuts are divided into four major categories:source traits,sink traits,source-sink comprehensive traits,and yield traits,and 18 sub-categories.Based on dimensionality reduction analysis,the contribution rates of the first five principal components were 28.64%,16.305%,16.197%,14.239%and 13.315%respectively,and the cumulative contribution rate was 88.7%,which could reflect most of the information of the 18 source-sink traits.The maximum value of the feature vector corresponding to each principal component can be used as the main index to evaluate the relationship between the source and sink of peanuts,and they are named as the source factor(leaf area at the pod-setting stage),the yield factor(pod fullness),the sink factor(flowering number),and late source factors(leaf area at full fruit stage)and late sink factors(needle formation rate,fruit rate).1.2 Source library type divisionThe tested peanut cultivars were clustered according to the source and sink trait scores and clustered into 4 categories.The first type is Jihua 5 and Weihua 8,we define this type of source-sink coordination type.Type II include Weihua 16,Jihua 18155,Zhonghua 24 and Yuhua 15,we define it few sufficient source-few sink type.Type III include Fenghua 1,Shanhua 9 and Rihua 1,we define it sufficient source-large sink type.Type IV cultivars are Qinghua 7,Huayu 33,Huayu 36,Yuhua 9326,we define it large source-few sink type.2 Differences in characters of Peanut cultivars with different Source-sink types2.1 The difference of the characteristics of peanut cultivars with different source-sink typesThere were significant differences in leaf area per plant between four types of peanut cultivars.The leaf area per plant of Huayu 36 was 2741 cm2,significantly higher than that of other cultivars.The daily decline rate of leaf area in late growth stage was 47.8cm2·d-1.The leaf area per plant of source-sink coordination variety Jihua 5 was 1468 cm2,while that of source-sink few-type variety Zhonghua 24 and source-sink polymorphism variety Shanhua 9was between them.There were significant differences in flowering quantity and flowering duration of peanut cultivars with different source-pool types.Shanhua 9 had the longest flowering time,followed by Jihua 5 and Zhonghua 24,and Huayu 36 had the shortest flowering time.The number of flowering per plant of Shanhua 9 was significantly higher than that of other cultivars,but the number of flowering per plant of Huayu 36 and Zhonghua 24 was less.Shanhua 9 had the highest needle formation rate,but the lowest fruit rate,the effective proportion and pod plumpness were significantly lower than other cultivars;Zhonghua 24 had the highest effective rate and higher effective proportion;Jihua 5 had higher effective proportion and pod plumpness than other cultivars.2.2 Differences in physiological characters of Peanut cultivars with different Source-sink typesThe content of chlorophyll a and total chlorophyll in the leaves of Huayu 36 was significantly lower than that of the other three cultivars,and the chlorophyll content of Shanhua 9 was lower at full fruit stage and harvest stage,which indicated that Shanhua 9 and Huayu 36 had a fast degradation rate of chlorophyll in the leaves in the late growth stage and a short green time in the later stage.There was no significant difference in the net photosynthetic rate of peanut leaves among different source and sink types at the anthesis stage.The net photosynthetic rate of Jihua 5 and Zhonghua 24 was higher at the pods and fruiting stages,while that of Huayu 36 was the lowest.The degradation rate of chlorophyll in the film was fast,and the green time of leaves in the later stage was short.The nitrate reductase activity of Jihua 5 and Zhonghua 24 at podding stage and full fruit stage was significantly higher than that of Shanhua 9 and Huayu 36.The activities of glutamine synthetase,glutamate synthetase,glutamate dehydrogenase and sucrose phosphate synthase and sucrose synthase of Jihua 5 were the highest,and the carbon and nitrogen metabolic enzyme activity of Huayu 36 was significantly lower than that of other cultivars.2.3 Differences in accumulation and distribution of assimilates among peanut cultivars with different source-sink typesThe population photosynthetic potential of the four cultivars was Huayu 36>Zhonghua24>Shanhua 9>Jihua 5.However,combining with the analysis of yield data,the yield of cultivars with higher photosynthetic potential did not necessarily increase.The total dry matter matter of Huayu 36 was the highest,followed by Shanhua 9 and Zhonghua 24,and Jihua 5was the lowest.However,the dry matter ratio of the pod bank of Jihua 5 exceeded the dry matter ratio of stem and leaf at 50d after flowering,the dry matter ratio of the pod bank of Shanhua 9 and Zhonghua 24 exceeded the dry matter ratio of stem and leaf at 60d after flowering,and the dry matter ratio of the pod bank of Huayu 36 exceeded the dry matter ratio of stem and leaf at 80d after flowering.2.4 Analysis of dominant proteome of source-sink coordination cultivars 36.7%of the differential proteins between Jihua 5 and Huayu 36 were related to the metabolic process,and 51.4%of the differential proteins between Jihua 5 and Shanhua 9 were related to the metabolic process.The differential proteins between Jihua 5 and Huayu 36 were involved in 75 different pathways,and the differential proteins between Jihua 5 and Huayu 36were involved in 92 different pathways.In the metabolic group,the number of differential proteins is mainly involved in energy metabolism systems such as carbon metabolism,glucose metabolism,amino acid metabolism,nitrogen metabolism and defense systems such as fatty acid metabolism,steroid biosynthesis,phenylpropane biosynthesis and so on.Compared with Huayu 36,a variety with large source and few reservoirs,and Shanhua 9,a source foot library multi-type variety,the source-sink coordinated variety Jihua 5 had acyltransferase(EC:2.3.3.8)during the TCA cycle from oxaloacetic acid to citric acid,C-O lyase during the conversion of citric acid to cis-aconitic acid and cis-aconitic acid to isocitrate(EC:4.2.1.3).The expression of dehydrogenase(EC:1.1.1.41)in the process of isocitrate conversion to ketoglutarate was significantly increased,indicating that active sugar metabolism was the physiological basis of high yield and good quality of source-sink coordinated cultivars.2.5 Differences in yield and quality characters of Peanut cultivars with different Source-sink typesIn this study,the yield of four peanut cultivars with different source and reservoir types showed that Jihua 5 had the highest yield,followed by Shanhua 9 and Zhonghua 24,and Huayu 36 had the lowest yield.In terms of yield components,the fruit number per kg of Jihua5 was the least,and that of Shanhua 9 was the most.Jihua 5 and Huayu 36 had higher kernel yield,while Shanhua 9 and Zhonghua 24 had lower kernel yield.Among the four cultivars,Zhonghua 24 had the highest crude lipid content,followed by Jihua 5,and Huayu 36,the lowest crude lipid content.3 Effects of changing source-sink ratio on source-sink characters and yield and quality formation of flowering studentsThere was no significant difference in the leaf area per plant between the control group and the peanut after removing 25%of the leaves,but the leaf area per plant was significantly lower than the control after removing 50%and 75%of the leaves.The leaf area per plant of peanut was higher than that of the control after deflowering,but the leaf area of peanut decreased after deflowering at 75%.The number of peanut pod library changed with the reduction of source.Appropriate reduction of source could reduce the number of ineffective needles and young fruits,and increase the number of effective fruits.However,excessive reduction of source could significantly reduce the total number of fruits and the number of effective fruits.The removal of some flowers will promote the formation of needles and fruit of the remaining flowers,reduce the needles and young fruits at harvest,and increase the effective proportion.Reducing source by 25%or storage by 50%can increase the ratio of storage to storage,pod plumpness and kernel yield of peanut,and thus increase the yield.With the decrease of the number of leaves,the crude lipid content in peanut kernels increased firstly and then decreased.In 2018 and 2019,the crude lipid content of seed kernel after 25%leaves removal was increased by 4.3%and 3.8%,respectively,compared with the control,while the crude lipid content of seed kernel after 75%leaves removal was decreased by 1.7%and 4.4%,respectively,compared with the control.The protein content of peanut kernel increased after source reduction,the soluble sugar content of peanut kernel decreased after25%and 50%leaves were removed,and the soluble sugar content of peanut kernel increased after 75%leaves were removed.The fat content of peanut kernel increased and the content of protein and soluble sugar decreased with the decrease of storage quantity.4 Effects of different regulation measures on the formation of floral source-sink characters,yield and quality4.1 Regulation effect of removal of growing points on the formation of floral source-sink characters,yield and qualityAfter the stem terminal growth,the height of peanut plant can be effectively reduced.30d after flowering and 45 d to stem the growing point can effectively reduce the harvest is not into Tu Guo pin number,and increase the full fruit number and proportion of effective pods,but after spending 15 d to stem the growing point increases not into Tu Guo pin number and the number of young fruit,reduce the number of full fruit,remove stalk end early point,may lead to early the regrowth of the nutrients to supply more in leaf,and reduce the allocation proportion of early in the development of pods,which leads to the early pods develop into full fruit to reduce the number of late flower needle and an increase in the number of young fruit development results,and therefore the yield significantly lower than control.For the cultivars with prosperous stems and leaves,we can choose to remove the stem tip growth point about45 days after flowering,reduce ineffective consumption,promote the transfer of assimilates to pods,improve pod plumpness,increase the number of full fruits,effective proportion and kernel yield,and increase yield.at the same time,because the crude fat content in the kernel is less affected,the oil pressing quality of the kernel can be guaranteed.4.2 Regulatory effects of spraying ethephon on Source-sink characters,yield and quality formation of PeanutThe inhibitory effect of ethephon on the number of peanut flowering was related to the spraying period.Spraying ethephon 10 and 20 days after anthesis could significantly inhibit flowering and reduce the number of peanut flowering per plant,and the inhibitory effect began the next day after spraying ethephon.Spraying ethephon 30 days after anthesis had no significant effect on the total flowering number per plant.The results showed that spraying at the initial flowering stage and full flowering stage could inhibit the number of flowering,but spraying ethephon had little effect on the flowering number of peanut,but spraying ethephon could significantly reduce the needle rate of flower formation,increase the number of chaff fruit and full fruit,and reduce the number of fruit needles at harvest.Spraying at 10 and 20days after anthesis could significantly increase the effective proportion,while spraying at 30days after anthesis had no significant effect on the effective proportion.Spraying ethephon could increase the leaf area per plant of peanut,and the increase of leaf area per plant was the largest 10 days after flowering,and the increase decreased with the postponement of spraying period.Spraying ethephon 10 and 20 days after anthesis significantly increased the photosynthetic rate of peanut leaves,but spraying 30 days after anthesis could only increase the photosynthetic rate in a short time,but had no significant effect on the photosynthetic rate of peanut leaves in the later growth stage.According to the comprehensive characters of source and sink,the source-sink relationship of spraying ethephon 20 days after anthesis was the most coordinated,which was beneficial to promote the transport of assimilates to pods,improve the effective proportion and pod plumpness,and thus increase the yield.Spraying ethephon at 10 and 20 days after anthesis could significantly increase the crude fat content and protein content and decrease the soluble sugar content,especially 20 days after anthesis.Therefore,spraying ethephon is an effective measure to solve the imbalance between source and sink of peanut.Ethephon should be sprayed 20 days after flowering.4.3 Regulatory effect of plastic Film thickness on Source-sink characters,yield and quality formation of PeanutThe fruiting rate and needle forming rate of plastic film thickness 0.01 mm were higher than those of plastic film thickness 0.006 mm treatment.The flowering number per plant and needle formation rate of 0.014 mm and 0.02 mm plastic film treatments were higher than those of other treatments,but the fruiting rate was lower.It shows that properly increasing the thickness of plastic film can increase the needle rate of flower formation and fruit rate,but too thick plastic film thickness will reduce the fruit rate.Increasing the thickness of plastic film can increase the plumpness of peanut pods,and properly increasing the thickness of plastic film can increase the ratio of sink to source,harvest index and kernel yield,which is beneficial to obtain high yield.0.01 mm and 0.014 mm plastic film treatment could increase the content of crude fat and decrease the content of soluble sugar in peanut kernel.0.02 mm and 0.03 mm plastic film treatments decreased the content of crude fat and increased the content of soluble sugar.In this study,plastic film thickness 0.01mm can increase the yield and improve the quality by increasing the fruiting rate,increasing the number of fruit per plant and the plumpness of pods,changing the source-sink relationship and the distribution of assimilates among source-sink. |
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