Sha Jian Chuan, Jia Zhi Hang, Xu Xin Xiang, Hou Xin, Li Bing Yu, Ge Shun Feng, Jiang Yuan Mao
College of Horticulture Science and Enginee-ring, Shandong Agricultural University/State Key Laboratory of Crop Biology, Tai'an 271018, Shandong, China.
Ying Yong Sheng Tai Xue Bao. 2019 Apr;30(4):1373-1379. doi: 10.13287/j.1001-9332.201904.011.
A field experiment was carried out in a six-year old 'Fuji3'/M26/Malus hupehensis Rehd. apple with N and C labeled tracers, to understand C assimilation capability and the characteristics of translocation and distribution of C-photosynthate and N to fruit under different nitrogen application levels (urea 0%, 0.6%, 1.2%, 1.8%, 2.4%, CK, N, N, N, N, respectively) to smear the leaves within 20 cm around the fruit at late stage of fruit enlargement. The results showed that, with the increases of urea application, the chlorophyll content, nitrogen content, net photosynthetic rate, sorbitol and sucrose content, sorbitol 6-phosphate dehydrogenase (S6PDH) and sucrose phosphate synthase (SPS) activities, C assimilation capability of leaves were first increased and then decreased, with the highest value in 1.8% urea smear treatment and the lowest value with the treatment of clear water. The C of self retention (self leaves and self branches) was the highest in clear water (81.6%) and the lowest in 1.8% urea smear treatment (63.5%). The C was mainly allocated to fruit, followed by unlabeled perennial branch, and the lowest in unlabeled leaves. With the increases of urea application, the C absorption of fruit was first increased and then decreased, with the highest value in 1.8% urea smear treatment (1.21 mg·g) and the lowest value in clear water (0.51 mg·g). The N absorption of fruit was enhanced with the increases of urea application. These results indicated that foliage application of urea solution improved translocation and distribution of leaf photosynthate and nitrogen to fruit with varying degrees, which was the highest in 1.8% urea smear treatment and could avoid excessive intake of nitrogen to fruit.
以6年生‘富士3’/M26/湖北海棠苹果为试材，利用N和C标记示踪技术，在果实膨大后期对果实周围20 cm范围内叶片涂抹不同施氮水平（分别为尿素0%、0.6%、1.2%、1.8%、2.4%，即CK、N₁、N₂、N₃、N₄）的尿素溶液，研究不同施氮水平下苹果叶片碳同化能力及光合产物碳和氮向果实的转运分配特性。结果表明，随着尿素施用量增加，叶片叶绿素含量、氮含量、净光合速率、山梨醇和蔗糖含量、山梨醇-6-磷酸脱氢酶（S6PDH）和蔗糖磷酸合成酶（SPS）活性及叶片碳同化能力均先升高后降低，其中1.8%尿素涂抹处理最高，清水处理最低。自身保留（自身叶片和自身枝条）的碳在清水处理中最高（81.6%），在1.8%尿素涂抹处理中最低（63.5%）。碳主要分配到果实，其次是未标记的多年生枝条，未标记叶片中最低。随着尿素施用量增加，果实碳吸收先增加后降低，1.8%尿素涂抹处理最高（1.21 mg·g），清水处理最低（0.51 mg·g）。果实氮吸收随尿素施用量增加而增强。这些结果表明，叶面喷施尿素溶液能不同程度地改善叶片光合产物和氮向果实的转运分配，其中1.8%尿素涂抹处理效果最佳，且能避免果实过量吸收氮。
