| Strawberry(Fragaria× ananassa)has high economic value,and the strawberry industry is one of the most promising industries in facility agriculture.China ranks first in both planting area and yield of strawberries in the world,and current strawberries can be harvested in winter and spring,covering 99% of the existing planting area.Everbearing strawberry can be harvested all year,especially in summer and autumn,only accounting for 1%,there is a huge potential.Everbearing strawberry can fill the gap of fresh fruits market in summer and fall.However,the bottleneck is the lack of everbearing strawberry cultivar suitable for summer and fall in China,and it is difficult to propagate due to the low stolon germination of everbearing strawberry.The strawberry variety ’Zijin Siji’ is released by Jiangsu Academy of Agricultural Sciences and is suitable for planting in most areas of China.This study explored the effects of different photoperiod(8 h/d,14 h/d,20 h/d)and light quality(white,red,blue and yellow green mixed light)in ’Zijin Siji’ stolons,agronomic traits,photosynthesis,chlorophyll fluorescence parameters,physical characteristics and the influence of the anatomical morphology of leaf blade can be detected and identified the optimum photoperiod and light mass,the possible mechanism of stolon germination under optimum photoperiod and photoperiod can be analyzed.The main conclusions are as follows:(1)There were no stolons under 8 h/d and 20 h/d,but an average of 0.19 stolons per plant was found at55 d under 14 h/d photoperiod.Compared with 8 h/ d and 20 h/ d,the index such as the net photosynthetic rate,transpiration rate,stomatal conductance and light absorption index ABS/RC,and promoted the accumulation of chlorophyll A,soluble sugar,soluble protein,total phenols and flavonoids had been significantly increased,while the thickness of mesophyll and palisade tissue,palisade cell length,palisade cell width and midvein thickness were decreased under 14 h/d.14 h/d could be used as a photoperiod parameter to promote stolon propagation in strawberry.(2)The stolon germination time of ’Zijin Siji’ strawberry under yellow-green mixed light was earlier than that of white light from the 95 th day to the 30 th day,the number of stolons increased from 0.13/plant to0.47/plant,and tertiary stolons can be found,while there was no stolon under the single blue or red light.Light treatment did not germinate stolons.The parameter such as the transpiration rate,stomatal conductance and net photosynthetic rate of strawberry plants were significantly lower,but the content of chlorophyll A was the highest,and the contents of total phenols and flavonoids in strawberry leaves were significantly increased.Leaf thickness,mesophyll thickness,upper epidermis thickness,lower epidermis thickness,palisade tissue thickness,palisade cell length,palisade cell width,sponge tissue thickness,midvein thickness,compactness CTR and palisade sea ratio were the highest under yellow-green mixed light.The chlorophyll(a+b)content,net photosynthetic rate,transpiration rate and stomatal conductance of strawberry leaves under single blue light treatment were the highest.The plant height,petiole length and carotenoid content in leaves of single red light treatment were the highest.The yellow-green mixed light could be used as a light parameter to promote stolon production.(3)Transcriptome and metabolome results showed that a total of 1173 differentially expressed genes were screened by yellow-green mixed light,compared with white light,and the differentially expressed genes were enriched in biological processes,cell composition and molecular functions.The five plant hormone signal transduction pathways of ABA,GAs,Auxin,CKs,and JA were enriched with different genes,including transcription factors such as PYL,DELLA,and MYC2.Significantly up-regulated GAs and downregulated ABA metabolism may be the key points of this study.The stolon occurrence of ’Zijin Siji’ was stimulated by the interaction of ABA and GA under yellow-green mixed light. |
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