Study On Difference Of Cell Membrane Permeability And Uptake And Retranslocation In Rape Cultivars With Different Boron Efficiency

Pot culture and solution culture were conducted to discuss the boron different of the boron efficient rapeseed (Brassica napus L.)cultivar'QY10'and the boron inefficient one 'Ba'in boron uptake, distribution retranslocation and the relationships between boron and the cell membrane composition with grafting techniques and 10B isotope tracer. Main results are as follows:1.Grafting experiments indicated that the yield of rape can be mainly affected by scion, while to some extent by the rootstock under boron deficiency. The boron content and accumulation of the high boron efficiency cultivar was the highest and that of the boron inefficiency cultivar was the least under boron deficient condition. The results suggested that the boron in rape was affected by both stock and scion.2.When boron is sufficient, the boron content and accumulation of all parts and whole plant accumulation of boron inefficient cultivar'Ba'were more than the boron efficient cultivars'QY10',but when the boron was deficiency it appeared opposite trend, especially the upper leaves. It showed that the boron inefficient cultivar 'Ba'needed more boron to grow than the boron efficient cultivar'QY10',and the boron absorption capacity of boron efficient rape cultivar'QY10'was higher than the inefficient one.3.Whether boron deficient or boron sufficient conditions, the proportion of water extractable boron accumulation in different parts of boron efficient rape cultivar'QY10' accounting for the total boron accumulation was higher than boron inefficient cultivar 'Ba'.With the increasing of boron concentration in culture medium, the proportion of water extractable boron accumulation of different parts of two different boron efficiency rape cultivars accounting for total boron accumulation were increased, and the water extractable boron accumulation of upper leaves was significantly higher than the lower leaves and roots.4.There were amount of significant difference in boron distribution proportion between the two different boron efficiency rapeseed cultivars under boron deficiency conditions.The proportion of boron in the upper leaves accounting for the whole plant of the two rape cultivars rose under boron deficiency conditions.The results showed that boron in the two rape cultivars can be retranslocated from the lower leaves to the upper. However, boron in the boron inefficient cultivar'Ba' can be retranslocated just under boron deficiency severely (0.005 mg·L-1),boron in the boron efficient cultivar'QY10'can be retranslocated efficiently under boron deficiency gently (0.05 mg·L-1).5.The 10B can be retranslocated from the soaked leaves to the upper leaves, the lower leaves and the root after boron starvation three day, but the two rape cultivars with different boron efficiency have different boron retranslocation capacity. The capacity of boron retranslocation in efficient rape cultivar'QY10'was better than the boron inefficient one when leaf was immersed in 10B solution one day. The trend was opposite when leaf was immersed in 10B solution three day.6 Compared to supply boron five day, when the root was immersed in 10B solution the newly take-up 10B in upper leaves and lower leaves of the boron efficient rape cultivar 'QY10'was upward, but the root was downward. The boron inefficient rape cultivar'Ba' was opposite. The experiment showed that supply boron after starvation the newly take-up boron in rapes with different boron efficiency give priority to the growth center----top young tissues, and the retranslocation capacity of boron efficient rape cultivar was better than the boron inefficient one.7. With the decreasing of boron concentration in culture medium, the cell membrane relative permeability and ion leakage of different parts of two rape cultivars increased or had upward trend. The increase extent of the cell membrane relative permeability and ion leakage of different parts of boron efficient cultivar'QY10'were significant less than boron inefficient cultivar'Ba',which show that the injury extent of cell membrane of boron efficient cultivar was smaller than the boron inefficient cultivar under boron deficiency conditions, and the ability of enduring boron stress of boron efficient cultivar was better than boron inefficient one.