Effects of low-light supplemental light at night on tomato growth,sucrose transport and related gene expression between source and sink

QIN Yanping; GUO Zhixin

doi:10.16861/j.cnki.zggc.2024.0545

Abstract：Nighttime supplemental light has become an important means of facility vegetable production,but strong light is mostly used,which consumes a lot of energy and has a high cost. However,the effect of low-light supplemental light at night on vegetable production is still unclear. To investigate the effect of low-light supplemental light at night on the growth and sucrose transport between source and sink,Micro Tom tomato was used as the material. From the four-leaf and one-heart stage to the mature green stage,two supplemental light treatments of 15(SL15)and 30(SL30)μmol·m-2·s-1 bellowing the light compensation point for 4 hours were carried out after turning off the light for 1 hour at night every day,with no light supplementation as the control( CK ). The results showed that both SL15 and SL30 treatments significantly increased plant height,stem diameter and fresh mass of tomato seedlings compared with CK. Supplemental light obviously improved root morphology and increased total root length,total surface area as well as root tip number. Supplemental light promoted flowering,manifested by increased the number of flowering plants and the total number of flowering plants. There was no significant difference in the above physiological indexes between SL15 and SL30. Com-pared with CK,SL15 treatment significantly reduced the sucrose content of mature leaves and stems(source),increased the sucrose content of fruits and roots(sink),and up-regulated the expression of sucrose transport genes SUT1,SUT4,SWEET10b,SWEET11b and SWEET14 to varying degrees in leaves,stems,fruits and roots. However,there was no significant difference in the overall sucrose content of leaves,stems,fruits and roots between CK and SL15 treatment. In addition,SL15 treatment significantly increased the content of abscisic acid that was related to sucrose transport,and improved the expression levels of its synthetic and signaling marker genes including NCED1,AAO3 and ABI5 in the leaves,stems,fruits and roots. In conclusion,nighttime low-light supplementation promotes tomato growth and sucrose transport between source and sink,which provides a new idea for promoting low-light supplementation to reduce the cost of supplemental light,and promotes the efficient and green development of facility vegetables.