Effects of machine transplanting density and panicle nitrogen fertilizer reduction on grains starch synthesis in good taste rice cultivars

Authors:
  • KLKun Liu
    Kun Liu
  • HZHong-Lu Zhang
    Hong-Lu Zhang
  • JWJia-Li Wei
    Jia-Li Wei
  • HZHao Zhang
    Hao Zhang
  • JGJun-Fei Gu
    Jun-Fei Gu
  • JYJian-Chang Yang
    Jian-Chang Yang
Open Access
Publisher website
Google Scholar
Abstract
The effect of machine transplanting density on grain starch synthesis in good taste rice cultivars (GTRC) is still unclear. In the experiment, three representative GTRC of Nanjing 9108, Nanjing 5055, and Nanjing 46 in Jiangsu province were used as materials. Five machine transplanting densities of 33.3 × 104, 27.8 × 104, 23.8 × 104, 20.8 × 104, and 18.5 × 104 hills hm-2 were formed with the row spacing at 30 cm and the plant spacing of 10, 12, 14, 16, and 18 cm, respectively. The effects of machine transplanting density on yield and grain starch synthesis in above three rice cultivars were studied, and the regulation mechanism of halving normal nitrogen (N) rate of panicle nitrogen fertilizer on the starch synthesis was also observed. The results were as follows: (1) The grain yield of the three GTRC were highest at the transplanting density of 27.8 × 104 hills hm-2. The amylose content at mature stage of the three GTRC decreased first and then increased with the increase in machine transplanting density, while the amylopectin content continued to decrease. When the machine transplanting density was controlled at 27.5 × 104-29.9 × 104hills hm-2, it was beneficial to improve the taste value of the above-mentioned GTRC. (2) With the increase in machine transplanting density, the activities of granule-bound starch synthase (GBSS) and ADP-glucose pyrophosphorylase (AGP) were increased in the early and middle stages of grain filling (8-20 days after heading), and were decreased rapidly at later grain filling stage. Machine transplanting density had no significant effect on starch branching enzyme (SBE) activity. Among them, the activities of GBSS and AGP in grains at 12-16 days after heading were significantly and positively correlated with the contents of amylose and total starch. (3) Compared with normal N rate of panicle nitrogen fertilizer, half normal N rate could significantly decrease the activities of GBSS and AGP in grains during the early and middle stages of grain filling, reduce the amylose content of rice, and further improve the taste value of GTRC. These results indicated that machine transplanting density could regulate the amylose content due to the activities variations of key enzymes involved in starch synthesis (GBSS and AGP) in the grains during the early and middle stages of grain filling, thus resulting in the difference of rice taste value. Reasonable machine transplanting density and panicle nitrogen fertilizer rate are helpful to further improve the eating quality of GTRC.

This publication has 32 references indexed in Scilit: