Department of Horticulture, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, Jiangsu, PR China.
Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, Japan.
Ann Bot. 2020 Jul 24;126(2):315-322. doi: 10.1093/aob/mcaa094.
Dutch tomato cultivars tend to have a greater yield than Japanese cultivars even if they are grown under the same conditions. Factors contributing to the increased yield of the Dutch cultivars were a greater light use efficiency and greater leaf photosynthetic rate. On the other hand, the relationship between tomato yields and anatomical traits is still unclear. The aim of this study is to identify the anatomical traits related to the difference in yield between Dutch and Japanese cultivars.
Anatomical properties were compared during different growth stages of Dutch and Japanese tomatoes. Hormone profiles and related gene expression in hypocotyls of Dutch and Japanese cultivars were compared in the hypocotyls of 3- and 4-week-old plants.
Dutch cultivars have a more developed secondary xylem than Japanese cultivars, which would allow for greater transport of water, mineral nutrients and phytohormones to the shoots. The areas and ratios of the xylem in the hypocotyls of 3- to 6-week-old plants were larger in the Dutch cultivars. In reciprocal grafts of the Japanese and Dutch cultivars, xylem development at the scion and rootstock depended on the scion cultivar, suggesting that some factors in the scion are responsible for the difference in xylem development. The cytokinin content, especially the level of N6-(Δ 2-isopentenyl) adenine (iP)-type cytokinin, was higher in the Dutch cultivars. This result was supported by the greater expression of Sl-IPT3 (a cytokinin biosynthesis gene) and Sl-RR16/17 (a cytokinin-responsive gene) in the Dutch cultivars.
These results suggest that iP-type cytokinins, which are locally synthesized in the hypocotyl, contribute to xylem development. The greater xylem development in Dutch cultivars might contribute to the high yield of the tomato.
即使在相同条件下种植，荷兰番茄品种的产量往往高于日本品种。导致荷兰品种产量增加的因素是更高的光能利用率和更高的叶片光合速率。另一方面，番茄产量与解剖结构特征之间的关系尚不清楚。本研究旨在确定与荷兰和日本品种产量差异相关的解剖结构特征。
在番茄不同生长阶段比较荷兰和日本番茄的解剖结构特性。在 3 周龄和 4 周龄植株的下胚轴中比较荷兰和日本品种下胚轴的激素谱及其相关基因表达。
荷兰品种比日本品种具有更发达的次生木质部，这使得更多的水分、矿质养分和植物激素能够输送到地上部分。3 周至 6 周龄植株下胚轴中木质部的面积和比例在荷兰品种中较大。在日本和荷兰品种的相互嫁接中，接穗和砧木的木质部发育取决于接穗品种，这表明接穗中的某些因素是木质部发育差异的原因。细胞分裂素含量，特别是 N6-（Δ2-异戊烯基）腺嘌呤（iP）型细胞分裂素的水平，在荷兰品种中较高。这一结果得到了荷兰品种中 Sl-IPT3（细胞分裂素生物合成基因）和 Sl-RR16/17（细胞分裂素响应基因）表达较高的支持。
这些结果表明，在下胚轴中局部合成的 iP 型细胞分裂素有助于木质部发育。荷兰品种中较大的木质部发育可能有助于番茄的高产量。
