不同磷营养油菜品种根系形态及生理特性差异研究

DIFFERENCES OF ROOT MORPHOLOGY AND PHYSIOLOGICAL CHARACTERISTICS BETWEEN TWO RAPE GENOTYPES WITH DEFFERENT P EFFICIENCY1

研究不同磷营养油菜对磷素的反应及其根系形态特征、生理特性等方面的差异，结果表明：磷高效油菜需磷量较小，而在缺磷时吸磷量较大；缺磷时两种油菜品种根冠比增加，且磷高效品种增加幅度大于磷低效品种；缺磷时，磷高效品种具有较长的根系，较大的根体积、根表面积与根活跃吸收表面积，而加磷时，两品种差异不大。油菜缺磷时，磷高效品种磷外渗率小于磷低效品种，加磷时两品种磷外渗率差异不大。缺磷时磷高效品种对磷的亲和力大于磷低效品种，加磷时磷高效品种中磷进入根系的最大净流量小于磷低效品种。

The two rape ( Brassica napus L) genotype with different P efficiency (HB:higer P efficiency, SH:lower P efficiency) were selected from 32 rape cultivas Further studies were carried out to the ability of P absorption; the root morphology such as root/shoot ratio, root length, root volume, root surface area and active absorb surface area; the physiological characteristic such as root membrane permeability, P efflux rate and kinetic parameters between two rape genotype under P deficiency and P adequate conditions The results showed that HB can take in more P from soil than SH The reason was that when P was deficient, HB maintained higher ratio of root to shoot, bigger root system, larger root surface area, higher root activity, stronger affinity to P, so it's uptake efficiency was higher; meanwhile, its root cell membrane permeability and P efflux rate decreased, so the net uptake rate was higher Under the P adequate conditions there was very little difference between two genotype of rape in ability to P absorption