Effect of Boron on Dynamic Change of Seed Yield and Quality Formation in Developing Seed of Brassica napus

Abstract

ABSTRACT Rapeseed (Brassica napus) is one of main oil crops in the world and also a potential bioenergy crop. Because of the sensitivity of Brassica napus to boron (B) deficiency and the wide distribution of low available-B soils in main areas of rapeseed production, more and more attention is being paid to the effect of B nutrition on yield and quality of rapeseed and its regulation mechanism. In this study, a field plot trial was conducted to examine the effects of B on dynamic changes of seed yield and quality formation in developing rapeseed. The results showed that B significantly increased seed yield compared with the low B control, which was attributed to an increase in the number of seeds per pod and pods per plant. During the seed development period, dry matter accumulation of seed followed a typical S-shaped curve at the two B treatments, but seed weight accumulated faster in plants supplied with sufficient B than those with low B. The dry weight of the podwall in high B treatment showed rapid increase at the early stage of seed development and decreased rapidly in later periods compared with low B. This suggested that applying B improved the accumulation of seed dry matter in early stages of seed development and substance transport from podwall to seed in later stages, which resulted in high seed yield. No significant effect of B on oil content, erucic acid and glucosinolate contents was found. However, B maintained a lower level of erucic acid and glucosinolate contents at whole seed development process and resulted in a lower ratio of erucic acid (22:1)/oleic acid (18:1) compared with that of low B treatment. These results suggested that application of B could heighten seed yield and improve oil quality for rapeseed in soils with low available B.