Effects of nitrogen forms on the development and quality of cherry tomato fruit

and 75% NO3-:25% NH4+. While, under the treatment with 100% NH4+, titratable acidity content is the highest at 7 DAF, and then decreases. Effects of different N forms on fruit anatomy and growth, and contents of metabolites related to fruit quality during the development of cherry tomato（Lycopersicon esculentum Mill.）fruit were studied by using matrix-nutrient solutions co-cultivated with 100% NO3-, 100% NH4+ and 75% NO3-:25% NH4+. The results are as follows: 1) In comparison to the treatment with 100% NO3-, shapes of epidermal cells of the fruits are more regular and have a closer arrangement, and cuticle is distributed evenly under the treatment with 75% NO3-:25% NH4+. While, among all the treatments, shapes of the epidermal cells are irregular and have a looser arrangement, and the cuticle is thinner at young fruit and green-ripe stages and is thicker at the mature stage under the treatment with 100% NH4+. 2) During the development of the fruit, individual fruit weight of the treatment with 75% NO3-:25% NH4+ shows a similar change tendency as that of the treatment with 100% NO3-, and the weight of the treatment with 75% NO3-:25% NH4+ is a little higher than that of the treatment with 100% NO3- at the maturation stage. While, under the treatment with 100% NH4+, the weight is significantly reduced since 14 days after flowering stage (DAF). 3) Content of amino acids of the fruits decreases gradually after 7 DAF under the treatment with 100% NO3-, but it decreases firstly, then increased from 14 to 21 DAF and decreased again in the treatment of 75% NO3-:25% NH4+. However, in the 100% NH4+ treatment, it showed a tendency like W. Total sugar contents under all the treatments increase at beginning, reach to the highest content at 21 DAF, and then decrease. Total sugar content under the with 100% NH4+ is higher that that of the other treatments. The change of titratable acidity content shows a single peak at 28 DAF in the treatments with 100% NO3-