【作者】 梁宏玲；

【导师】 徐芳森；

【作者基本信息】 华中农业大学 ， 植物营养学， 2005， 硕士

【摘要】 磷是植物生长必需的营养元素之一,而油菜对低磷反应极为敏感,本研究目的在于进一步理解和揭示甘蓝型油菜磷高效的生理机理,为研究甘蓝型油菜磷营养高效的遗传和分子生物学基础提供依据。 本研究利用盆栽试验,根箱试验和水培试验,以甘蓝型油菜磷高效品种97081和磷低效品种97009为材料,研究了两个品种在磷正常和低磷胁迫下,植株生长,根系形态,磷的吸收利用,酸性磷酸酶活性以及根际土和非根际土无机磷分级等方面的内容,主要结论如下: 1.磷高效品种具有适应低磷胁迫的生物学特性 对盆栽试验苗期、蕾苔期和根箱试验两个品种的生长状况进行调查,发现在不同磷水平下,磷高效品种97081的生长状况均优于磷低效品种97009,具体表现为:97081与97009比出叶速度快,叶片数多,生长较快,叶面积大、抽苔较早,而且根系也较97009发达,因而导致97081干物质量高于97009,较早完成其生活史。说明磷高效品种97081具有适应低磷胁迫的生物学特征,表现磷高效。 2.磷高效品种具有较强的磷吸收利用能力 盆栽试验分苗期和蕾苔期不同部位取样,根箱在蕾苔期收获,也分不同部位取样,分析样品磷含量。发现在不同磷水平下,磷高效品种97081植株体内磷含量均低于97009,说明97081单位磷可以建成较多的干物质,有较强的磷利用效率。用磷含量和干物质量的乘积求得磷累积量,发现在不同磷水平下,磷高效品种97081磷累积量高于97009,说明磷高效品种97081比97009有较强的磷吸收能力。苗期两个品种的磷含量和磷累积量差异达到显著和极显著水平,而盆栽试验蕾苔期和根箱试验的结果表现不太一致,可能是由于两个试验的外部环境温度不同的原因,可见外部环境温度是油菜表现磷高效的一个重要因素。 3.磷高效品种具有较强的磷再利用能力 对水培试验的样品分不同部位取样,测定磷组分,发现低磷胁迫下,磷低效品种97009和磷高效品种97081可溶性磷占总磷的比例均表现为,下部叶>上部叶,磷高效品种97081根、上部叶和下部叶可溶性磷占总磷的比例均高于磷低效品种97009。可溶性磷占总磷的比例高,则可移动性磷比例高,供应新生叶片生长所需磷的机会多,磷高效品种97081磷的再利用能力较强。 4.磷高效品种具有较高的酸性磷酸酶活性 对水培样品分不同部位取样,测定植株体内酸性磷酸酶(APase)活性,发现降低营养液的磷浓度,植株体内的APase活性增加,其中叶片APase活性增加达到显著和极显著水平,根部APase活性增加不显著,并更多还原

【Abstract】 Phosphorus (P) is one of the necessary nutrient elements. Brassica napus was sensitive to P deficiency. The aim of this study was to understand and unveil P-efficient physiological mechanism of Brassica napus, and to afford some bases for studying the molecular biology of P-efficiency in Brassica napus.P-efficient cultivar 97081 and P-inefficient cultivar 97009 were used to study oil rape growth, root character, uptake and utilization of P, acid phosphase activity, and inorganic P fraction of rhizosphere and bulk soils with pot culture, root box culture and solution culture, respectively. And the main results were as follows:1. P-efficient cultivar 97081 had the biological character to adapt P deficiency. Growth statuses of the two cultivars in seeding and bolting stage with pot culture and root box culture were investigated, respectively. The growth statuses of 97081 were better than those of 97009 under different P levels. P-efficient cultivar 97081 had more leaves, larger leaf area, root system, higher stem, bolting earlier and accumulated much weightier dry weight than P-inefficient cultivar 97009, and the growth rate of 97081 was faster than 97009, and had shorter growth period. Therefore, 97081 had the biological character to adapt P deficient condition well, and showed P efficiency.2. P-efficient cultivar 97081 had stronger ability to absorb and utilize P. Samples from different parts of the two cultivars in seeding stage and bolting stage with pot culture and bolting stage with root box culture were harvested, and then P content in these samples was determined. The results showed that P content in 97081 was lower than that of 97009, but 97081 can produce more dry biomass production using unit P absorbed than 97009, which suggested that 97081 had higher P utilization efficiency than 97009. Although P content in 97081 was lower than that of 97009, 97081 accumulated more P. The differences in P uptake and accumulation at seeding stage were more significant than at other stage. The results of bolting stage with pot culture and root box culture were different, which probably due to the effect of environment temperature on plant P uptake.It suggested that environment temperature was an important factor for plant to absorb P and grow normally.3. P-efficient cultivar 97081 had stronger ability to reutilize P. Total P in samples from a nutrition solution culture was fractionated into soluble P and insoluble P. Soluble P proportion in total P in old leaves was higher than young leaves in both two cultivars under P deficiency. However, soluble P proportion in total P in roots, young leaves and old leaves of 97081 was higher than of 97009, which suggested that relative mobilizable P in 97081 was more than that in 97009, P in old leaves could recycle to provide P for young leaves. And P-efficient cultivars 97081 had a higher ability to reutilize P.4. P-efficient cultivar 97081 had higher acid phosptase (APase) activity. Samples from solution culture were used to to determine APase activity, and we found that APase activity improved significantly with decreased P level in solution. The activity of different parts in plant was different: APase activity in root was higher than in old leaves, APase activity in old leaves was higher than in young leaves. APase activity in root was highest, which was propitious to excrete into medium in order to hydrolyze and absorb more organic P. APase activity in 97081 was higher than in 97009, and the increased degree of the APase activity in 97081 was higher than that in 97009 from P sufficiency to P deficiency, which suggested that 97081 can more highly improve P mobilization in plant than 97009. These results were coincident with the results of P fractions of plant.5. P-efficient cultivar 97081 had stronger ability to activate and utilize insoluble P in soil. The soil from root box culture was parted into rhizosphere and bulk soil. We determined available P content and inorganic P fractions. The content of available P, Al-P and Fe-P in rhizosphere soil for planting P-efficient cultivar 97081 was lower than that for planting P-inefficient cultivar 97009, respectively, which suggested that 97081 probably had a stronger ability to mobilize and absorb Al-P and Ca-P in soil than 97009. Compare to the results of P accumulation in plants, P-efficient cultivar 97081 had a stronger ability to activate and absorb insoluble P was proved again. But the mechanism and the difference in P fraction in bulk soil were expected to study further.更多还原