Characterization of the growth and fruit quality of tomato grafted on a woody medicinal plant, Lycium chinense

Abstract

Grafting has been widely used in vegetables, particularly in the plants of Solanaceae and Cucurbitaceae families because of its many significant advantages. Substantial studies have revealed that grafting can affect the yield and fruit quality of tomato through the vigorous rootstocks as reported previously. The selection of rootstocks plays an important role in improving the fruit yield and quality of scions. Lycium species (popularly known as goji or goji berry), also belonging to the Solanaceae family, is widely used as the functional fruits and vegetables, as well as traditional Chinese herbs. Goji plants also exhibit the excellent salt-tolerant ability. The intergeneric grafting across different genera, importantly with tomato and plant from different genus is little described. In this study, two commercial cultivars of tomato, Zhongshu 5 (ZS5) and TA209 as scions were grafted on goji plants (L. chinense Mill.), and the growth and fruit quality of tomato were investigated. The ungrafted self-rooted tomato plants were used as the control plants. The results showed that the growth of the grafted tomato plants was slightly depressed by grafting at the early development, but was restored like the self-rooted plants during the late development, and the net photosynthetic rate and chlorophyll content were higher in the grafted plants’ leaves at the fruit ripening stage. The size, shape, fresh weight and pigmentation pattern of tomato fruits were remarkably affected by grafting. Grafting produced smaller tomato fruit with lower fresh weight. An interesting observation was noticed that the pigmentation pattern of tomato fruits was close to that of goji berry. Some traits associated with fruit quality were improved by grafting approach, including total soluble solids (TSS), titratable acidity (TA), ratio of TSS/TA and vitamin C (Vc). The natural amino acids and nine mineral elements in tomato fruits were also affected by grafting. It was suggested that the increase of fruit quality may be attributed to the reduction of fruit water content and the effect of rootstock. This is the first report on intergeneric grafting between tomato and goji plants. The grafting procedure had a remarkable influence on the growth and fruit quality of tomato plants. With the perspective of high salt-tolerance of goji rootstocks, it is well worthy to study the performance of grafted tomato under saline condition in future.