Plant polyploidy often occurs in conjunction with higher yield and superior quality.Therefore,obtaining polyploid germplasms is a significant part of breeding.The oil-tea Camellia tree is an important native woody pla...Plant polyploidy often occurs in conjunction with higher yield and superior quality.Therefore,obtaining polyploid germplasms is a significant part of breeding.The oil-tea Camellia tree is an important native woody plant that produces high-quality edible oil and includes many species of Camellia with different ploidies.However,whether higher ploidy levels in oil-tea Camellia trees are related to better traits remains unclear.In this study,the ploidy levels of 30 different oil-tea Camellia strains in three different species in the Sect.Paracamellia were determined by flow cytometry and chromosome preparation,and the phenotypic characteristics and fatty acid compositions of the fruits were examined by field observations and laboratory analyses.The correlations between the ploidy level of oil-tea Camellia and the main traits of the fruit were investigated.Our results showed that 10 Camellia lanceoleosa strains were diploid,10 Camellia meiocarpa strains were tetraploid and 10 Camellia oleifera strains were hexaploid.Hexaploid C.oleifera had larger fruit size and weight,more seeds per fruit,greater seed weight per fruit,higher oil content and greater yield per crown width than tetraploid C.meiocarpa and diploid C.lanceoleosa,but their fruit peel thickness and fresh seed rate were significantly lower,and these traits were significantly correlated with ploidy level.In addition,in terms of fatty acid composition,hexaploid C.oleifera had a higher oleic acid content than tetraploid C.meiocarpa and diploid C.lanceoleosa,but their linoleic acid,linolenic acid and arachidonic acid contents were lower.The contents of palmitic acid,stearic acid and total unsaturated fatty acids were not significantly correlated with ploidy level.In conclusion,certain correlations exist between the main characteristics of oil-tea Camellia fruit and the ploidy level,and increasing the ploidy level led to an increase in fruit yield with no effect on oil composition.The discovery of variations in the main characteristics of oil-tea Camellia fruit with different ploidies will facilitate germplasm innovation and lay a foundation for ploidy breeding and mechanistic research on fruit traits.展开更多
Oil-tea camellia tree is an important oil plant in China that has long flexible branches.The most challenging feature for the mechanized harvest of oil-tea fruits is that its flower and fruit grow synchronously.In ord...Oil-tea camellia tree is an important oil plant in China that has long flexible branches.The most challenging feature for the mechanized harvest of oil-tea fruits is that its flower and fruit grow synchronously.In order to improve the harvesting efficiency and avoid damaging the flower bud,a hand-held fruit harvesting machine with a variable spacing comb brush was proposed.The harvesting machine can generate three kinds of actuation to detach fruit when it runs.The main actuation results from the brushing of multiple comb fingers.The other two kinds of actuation result from the beating of comb fingers on the fruits and the branches.The finger spacing of the comb brush can be adjusted consequently through moving the spacing adjusting crossbar.Hence,when the finger spacing is smaller than the diameter of the oil-tea fruit,the fruit is brushed off,but the flower bud and leaf pass through the finger gap.When the finger spacing is bigger than the fruit diameter,the fruit stuck between the fingers is loosened to ensure the continuous operation of the machine.Nylon was used as the material of the brush finger to avoid damage,which can also reduce the overall weight.The dynamic simulation of the harvesting machine was carried out with ADAMS,and the acceleration of the front end of the comb finger and the variation of the finger spacing were analyzed.The prototype of the harvesting machine was built and tested in the field.Field experiment results showed that when the speed of the comb finger drive shaft was 480 r/min,the average harvesting percentage of oil-tea fruit was 80%,and the flower bud was seldom detached,which met the working requirements of oil-tea fruit harvesting.展开更多
基金supported by the Special Funds for Construction of Innovative Provinces in Hunan Province,China(2021NK1007)the Hunan Provincial Innovation Foundation for Postgraduate,China(CX20230779)the Scientific Innovation Fund for Post-graduates of Central South University of Forestry and Technology,China(2023CX01009)。
文摘Plant polyploidy often occurs in conjunction with higher yield and superior quality.Therefore,obtaining polyploid germplasms is a significant part of breeding.The oil-tea Camellia tree is an important native woody plant that produces high-quality edible oil and includes many species of Camellia with different ploidies.However,whether higher ploidy levels in oil-tea Camellia trees are related to better traits remains unclear.In this study,the ploidy levels of 30 different oil-tea Camellia strains in three different species in the Sect.Paracamellia were determined by flow cytometry and chromosome preparation,and the phenotypic characteristics and fatty acid compositions of the fruits were examined by field observations and laboratory analyses.The correlations between the ploidy level of oil-tea Camellia and the main traits of the fruit were investigated.Our results showed that 10 Camellia lanceoleosa strains were diploid,10 Camellia meiocarpa strains were tetraploid and 10 Camellia oleifera strains were hexaploid.Hexaploid C.oleifera had larger fruit size and weight,more seeds per fruit,greater seed weight per fruit,higher oil content and greater yield per crown width than tetraploid C.meiocarpa and diploid C.lanceoleosa,but their fruit peel thickness and fresh seed rate were significantly lower,and these traits were significantly correlated with ploidy level.In addition,in terms of fatty acid composition,hexaploid C.oleifera had a higher oleic acid content than tetraploid C.meiocarpa and diploid C.lanceoleosa,but their linoleic acid,linolenic acid and arachidonic acid contents were lower.The contents of palmitic acid,stearic acid and total unsaturated fatty acids were not significantly correlated with ploidy level.In conclusion,certain correlations exist between the main characteristics of oil-tea Camellia fruit and the ploidy level,and increasing the ploidy level led to an increase in fruit yield with no effect on oil composition.The discovery of variations in the main characteristics of oil-tea Camellia fruit with different ploidies will facilitate germplasm innovation and lay a foundation for ploidy breeding and mechanistic research on fruit traits.
基金This work was supported by the Zhejiang Provincial Key Research&Development Plan(Grant No.2019C02065)the National Natural Science Foundation of China(Grant No.31971798)+1 种基金the National Key Research and Development Program of China(Grant No.2019YFD1001602)the 521 Talent Plan of Zhejiang Sci-Tech University,and the Cultivation Project for Youth Discipline Leader in Zhejiang Provincial Institute.
文摘Oil-tea camellia tree is an important oil plant in China that has long flexible branches.The most challenging feature for the mechanized harvest of oil-tea fruits is that its flower and fruit grow synchronously.In order to improve the harvesting efficiency and avoid damaging the flower bud,a hand-held fruit harvesting machine with a variable spacing comb brush was proposed.The harvesting machine can generate three kinds of actuation to detach fruit when it runs.The main actuation results from the brushing of multiple comb fingers.The other two kinds of actuation result from the beating of comb fingers on the fruits and the branches.The finger spacing of the comb brush can be adjusted consequently through moving the spacing adjusting crossbar.Hence,when the finger spacing is smaller than the diameter of the oil-tea fruit,the fruit is brushed off,but the flower bud and leaf pass through the finger gap.When the finger spacing is bigger than the fruit diameter,the fruit stuck between the fingers is loosened to ensure the continuous operation of the machine.Nylon was used as the material of the brush finger to avoid damage,which can also reduce the overall weight.The dynamic simulation of the harvesting machine was carried out with ADAMS,and the acceleration of the front end of the comb finger and the variation of the finger spacing were analyzed.The prototype of the harvesting machine was built and tested in the field.Field experiment results showed that when the speed of the comb finger drive shaft was 480 r/min,the average harvesting percentage of oil-tea fruit was 80%,and the flower bud was seldom detached,which met the working requirements of oil-tea fruit harvesting.
