不同形态氮素对樱桃番茄果实发育和品质的影响

采用基质营养液共培养法，研究了不同形态氮素及配施对樱桃番茄果实解剖结构、果实生长以及发育过程中与品质有关的生理指标的影响。结果表明:1）与全硝（100% NO3-）处理相比，铵硝配施（75% NO3-∶25% NH4+）处理下果实表皮细胞形状更加规则，排列紧密，且角质层覆盖均匀；全铵（100% NH4+）处理的果实表皮细胞形状不规则，排列疏松，其角质层厚度在幼果期和绿熟期显著低于另两个处理，在成熟期显著增加。2）全硝和铵硝配施处理果实单果重变化一致，成熟期铵硝配施处理单果重略高。花后14 d全铵处理显著降低单果重，抑制植株生长，并缩短生育时期。3）氮素形态显著影响果实发育过程中氨基酸的变化:全硝呈持续下降趋势，铵硝配施先下降后升高又持续下降，全铵则呈W型。不同形态氮素处理下果实总糖含量均先升后降，于花后21 d达到高峰，此时全铵处理的总糖显著高于另两个处理。全硝及铵硝配施处理下可滴定酸度呈单峰曲线，花后28 d达到最高值；全铵处理在花后7 d含量最高，随后逐渐下降。

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

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 solu-tions co-cultivated with 100% NO_3~- , 100% NH_4~+ and 75% NO_3~- :25% NH_4~+ . The results are as follows: 1) In comparison to the treatment with 100% NO_3~- , 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 % NO_3~- :25 % NH_4~+ . 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% NH_4~+ . 2) During the devel-opment of the fruit, individual fruit weight of the treatment with 75 % NO_3~- : 25 % NH_4~+ shows a similar change tendency as that of the treatment with 100% NO_3~-, and the weight of the treatment with 75% NO_3~- :25% NH_4~+ is a little higher than that of the treatment with 100% NO_3~- at the mature stage. While, under the treatment with 100% NH_4~+ , the weight is significantly reduced since 14 days after flowering stage (DAF). 3) Content of amino acids of the fruits decreases grad-ually after 7 DAF under the treatment with 100% NO_3~-, but it decreased firstly, then increased from 14 to 21 DAF and decreased again in the treatment of 75% NO_3~- :25% NH_4~+ . However, in the 100% NH_4~+ treatment, it showed a tenden-cy 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% NH_4~+ 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% NO_3~- and 75% NO_3~- :25% NH_4~+ . While, under the treatment with 100% NH_4~+ , titratable acidity content is the highest at 7 DAF, and then decreases.