Abstract:

In the current study,the pepper（Capsicum annuum L.）cultivar‘Bola Hongshuai’was used to explore the effects of supplemental lighting on the growth,photosynthetic characteristics,carbohydrate accumulation,root colonization by arbuscular mycorrhizal fungi（AMF）,and phosphorus absorption at the seedling stage. The results showed that compared with the control,supplemental red and blue light could significantly increase the biomass and seedling index of pepper seedlings;however,compared with the supplemental blue light,supplemental red light had more profound stimulating effects on the light-saturated photosynthetic rate,the accumulation of photosynthetic pigments,and the proportion of total sugar and sucrose content in the roots. Notably,red and blue light treatments were both conducive to the accumulation of strigolactones in roots but the former was more obvious. Moreover,supplementation of red and blue light during the seedling stage significantly promoted the colonization of roots by AMF and increased the dry weight,the accumulation of strigolactone content in roots,the expression of PT4 and PT5 genes,the phosphorus content and phosphorus concentration in pepper under the following condition of white light and phosphorus deficiency. However,compared with other light conditions,these responses were more profound when supplemented with red light. Taken together,the study revealed that supplementation of red light during the seedling stage was the most beneficial to the growth of pepper seedlings,and the accumulation of carbohydrates and strigolactones in the roots,which in turn promoted the colonization of roots by AMF and the phosphorus absorption in pepper seedlings.

Key words: pepper, supplementary light, carbohydrate, strigolactone, arbuscular mycorrhiza fungi, phosphorus absorption