蓖麻同源基因组加倍对生长与籽粒性状的影响OA

Castor bean(Ricinus communis L.),an important non-edible oilseed crop worldwide,urgently requires improvement in seed yield to meet the rapidly increasing industrial demand for castor oil.Polyploid breeding is an effective strategy for enhancing plant growth and yield-related traits.Previous studies on the phenotypic effects of whole-genome duplication have mainly focused on allopolyploids,whereas much less is known about variation in growth and yield traits in autopolyploid plants.Here,we inves-tigated growth,physiological,and seed traits in castor bean using a synthetic autotetraploid generated by chromosome doubling of a diploid line,thereby providing a theoretical basis for polyploid breeding and genetic improvement in castor and other oilseed crops.To this end,the diploid castor variety ZB306 and its synthetic autotetraploid counterpart were used as experimental materi-als,and their ploidy levels were verified by flow cytometry and somatic chromosome counting.Morphological,anatomical,pho-tosynthetic,and seed traits were then compared between tetraploid and diploid plants.The results showed that the genome size and chromosome number of tetraploid castor(2n=4X=40)were twice those of diploid castor,confirming that the tetraploid plants were true autotetraploids.Compared with diploid plants,tetraploids exhibited significantly greater plant height,basal stem diameter,leaf area,and leaf thickness.Stomatal length and width were also significantly greater in tetraploid leaves,whereas stomatal density showed a decreasing trend.Anatomical observations further revealed that both cell size and cell number in the lower epidermis,xylem,and parenchymatous tissues,as well as cell size in the palisade tissue,were significantly greater in tetraploid leaves than in diploid leaves.In addition,chlorophyll content,net photosynthetic rate,and transpiration rate were sig-nificantly higher in tetraploids than in diploids.Seed-related traits,including seed length,width,thickness,hundred-seed weight,and endosperm oil content,were also significantly greater in tetraploids than in diploids.Overall,autotetraploid castor plants ex-hibited enhanced vegetative growth and superior yield-related traits compared with their diploid counterparts.These findings not only provide a theoretical basis for polyploid breeding and genetic improvement in castor and other oilseed crops,but also lay the foundation for further studies on the molecular mechanisms underlying trait variation following polyploidization.