[Objective] The aim of the present study was to investigate the characteristics of calcium （Ca）, magnesium （Mg） and iron （Fe） subcellular distributions in oilseed rape （Brassica napus L.） leaves during cold acclimatization. [Method] A field experiment was conducted at two contrasting environments with three replicates and included a freezing sensitive variety （cv. Zhongshuang No. 11, ZS） and a freezing tolerant variety （cv. Ganyouza No. 1, GY）. [Result] The concentrations of Ca, Mg and Fe were significantly increased in plants roots, and the concentrations of Ca and Mg were significantly decreased but the Fe concentration was significantly increased in plants shoots. In leaves, the Ca concentration stored in soluble fraction was significantly increased and the Ca concentration of organelle-contained fraction and cell wall-associated fraction were significantly decreased with experiment time. The Mg concentrations stored in soluble fraction, organelle-contained fraction and cell wall-associated fraction were decreased with time. In contrary, the Fe concentration stored in soluble fraction, organelle-contained fraction and cell wall associated-fraction was significantly increased with time. Meanwhile, the changes of these measures of ZS were much higher than those of GY during cold acclimatization, which might be due to the GY is a freezing tolerant variety but ZS is not. [Conclusion] These results suggested that increasing the concentrations of Ca, Mg and Fe in plants shoots might increase the cold resistance of oilseed rape.
[Objective] The paper was to explore the impact of 5-aminolevunic acid（ALA）treatment on growth of winter oilseed rape（Brassica napus L.）seedlings and its mechanism.[Method] The effects of ALA on abscisic acid（ABA）contents in plant organs and xylem saps were investigated through hydroponic experiment.Four treatments including seed soaking with 0,25,50 and 75 mg/L ALA solutions（CK,A1,A2 and A3）for 6 h were set in the test.[Result] In addition to A3 treatment which made the dry weights of oilseed rape seedlings slightly decrease,after seed soaking with ALA,dry weights,net photosynthetic rate（Pn）,transpiration rate（Tr）and stomatal conductance（Gs）of plants significantly increased compared with control.ABA concentrations in plant shoots and xylem saps increased in different levels after seed soaking with ALA.[Conclusion] The increasing endogenous ABA contents might be an explanation for promotion effect of ALA application on the growth of winter oilseed rape seedling.
[Objective] The aim of this paper is to investigate the influences of exogenous 5-aminolevulinic acid （5-aLA） application on the growth and mechanism of winter oilseed rape （Brassica napus L.） before winter. [Method] For this purpose a split-plot experimental design with four treatments of seed soaking with 0,25,50 and 75 mg/L ALA solution （CK,A1,A2 and A3） was carried out from October 2009 to January 2010 in order to observe the influences upon the growth and relevant physiological indexes of Zhongshuang 9. [Result] Seed soaking with ALA solution significantly promotes the growth of double-9 before winter,which is probably due to the fact that ALA application enhances its photosynthesis,absorption of nutrients,and its anti-oxidation abilities. The research also finds that ALA treatment notably increases its photosynthetic pigment contents,root activities,leaf nitrate reductase activities,soluble sugar contents,antioxidase activities,and significantly decreases malondialdehyde（MDA） content. [Conclusion] These results indicate that seed soaking with 50 mg/L ALA solution might have a potential application in increasing the productivity of winter oilseed rape in agricultural management.
