【作者】 任丽英；

【导师】 朱端卫；

【作者基本信息】 华中农业大学 ， 植物营养学， 2009， 博士

【摘要】 用人工合成的方式,合成了不同形态的含硼针铁矿和含硼水锰矿,通过将它们引入到黄棕壤中,来研究含硼氧化物中硼的植物有效性及含硼氧化物对土壤性质的影响,主要研究结果如下：1、对针铁矿,水锰矿以及它们的含硼氧化物的合成方法进行了论述,并从氧化物的比表面积,扫描电镜照片和氧化物的硼含量等方面讨论了不同氧化物的性质差别,对氧化物特性有一个初步的了解。结果表明：针铁矿的比表面积和水锰矿的变化规律一致,即硼包被态氧化物>普通氧化物>硼吸附态氧化物。并且铁氧化物扫描电镜结果显示硼包被态针铁矿的颗粒明显比普通针铁矿和硼吸附态针铁矿要细,这和硼在氧化物上的结合形式有关。通过不同的提取方式测定了氧化物中硼的含量,发现针铁矿和水锰矿两种氧化物中硼的含量有很大的差别,含硼针铁矿中硼的含量远远高于含硼水锰矿。并且硼吸附态氧化物和硼包被态氧化物的硼含量也有很大的差别,硼吸附态针铁矿中硼的有效性远远高于硼包被态针铁矿,而水锰矿两种负载体中硼有效性的差异相对较小。2、通过在黄棕壤上添加不同量的氧化物,我们研究了含硼氧化物随着添加量的增加对土壤硼含量,土壤酸度变化以及油菜硼含量和油菜生物量的影响。结果发现,随着含硼针铁矿在土壤中添加量的增加,土壤中硼含量和油菜中硼含量也呈现一个逐渐升高的趋势,并且当含硼针铁矿的添加量达到5或10 g kg-1土时,土壤和植物中硼的含量呈现一个急剧的上升现象,但是普通针铁矿随着添加量的增加对土壤和油菜中硼含量却有一个小幅度的降低作用。不同量的含硼水锰矿对土壤和油菜硼含量的影响也呈现一种随添加量增加而增加的趋势。随着含硼氧化物添加量的增加,油菜的生物量呈现逐渐增加的趋势,在氧化物的添加量为3 g kg-1土时油菜生物量达到最大值。含硼铁锰氧化物对土壤酸度的改变呈现明显的剂量关系,含硼铁氧化物对土壤酸度的改变呈现稳定的升高趋势,而含硼水锰矿对土壤酸度的影响在2 g kg-1土时出现一个明显的转折点。综合以上现象,我们将2-3 g氧化物kg-1土的添加剂量作为我们进一步研究的最佳剂量。3、通过盆栽试验的方式,将人工合成的含硼铁锰氧化物引入土壤,研究含硼氧化物对土壤中不同形态硼含量以及油菜硼吸收的影响。结果发现,含硼铁锰氧化物的引入均不同程度地提高了土壤水溶态硼,非专性吸附态硼,专性吸附态硼及铁铝氧化物结合态硼的含量。其中含硼针铁矿对土壤不同形态硼含量的提高作用要远远大于含硼水锰矿。含硼铁锰氧化物的引入也大大促进了油菜对硼的吸收,提高了油菜地上部和根部的硼含量。通过对土壤不同形态硼含量与油菜硼含量进行简单线性回归分析发现,土壤中水溶态硼,非专性吸附态硼,专性吸附态硼及无定形铁铝氧化物结合态硼含量均与油菜地上部和根部的硼含量有很大的相关性。但逐步回归发现只有水溶态硼和无定形铁铝氧化物结合态硼含量与油菜硼含量存在直接的相关关系,这说明不仅土壤水溶态硼含量可以作为诊断植物有效性的指标,而且铁铝氧化物固定态硼在保持植物对硼吸收利用方面也有重要作用。4、含硼氧化物的引入改善了土壤中硼,钙,镁,铁,锰,铜,锌的有效性。并促进了油菜对这些养分的吸收利用,进而提高了油菜生物量。通过对土壤中养分含量与油菜生物量进行回归分析发现,土壤中钙和镁的含量与油菜生物量之间有显著的相关性。但是多重回归的结果则显示只有钙的含量显著影响油菜生物量的累积。可见,含硼氧化物提供植物硼营养只是植物对养分吸收的一个前提,而真正促进油菜生长的原因可能是含硼氧化物的加入为油菜吸收利用养分提供了一个有利的环境。5、通过根箱试验,研究了含硼氧化物的加入对根际土壤性质的影响。结果发现,含硼氧化物的加入对根际土壤性质产生了很大的影响。其中交换性酸,交换性钙和交换性镁的含量均表现出正根际效应,而根际土壤pH和交换性钾的含量却比非根际低。含硼氧化物的加入也刺激了土壤酶活性的变化,其中根际土壤过氧化氢酶和多酚氧化酶的活性比非根际高,而转化酶和酸性磷酸酶的活性却比非根际土壤低。通过WinRHIZO 2.0根系扫描仪对油菜根系形态进行了分析。结果发现,含硼氧化物的加入促进了油菜根系的生长,它们增加了包括总根长,根尖数,根体积和根表面积在内的油菜根系形态指标。6、通过盆栽试验,研究了含硼氧化物在黄棕壤上的添加对油菜生理指标的影响,结果发现含硼氧化物很大程度上提高了油菜的生理适应性。与对照相比,含硼氧化物的加入均提高了油菜叶片叶绿素的含量,可溶性糖含量,以及油菜的根系活力,且降低了油菜叶片中丙二醛和脯氨酸的积累。7、通过将含硼氧化物负载到石英砂上,用砂培的方式获得较单一的氧化物体系,从而清楚地观察到氧化物中硼的释放规律,该规律可以阐明含硼氧化物中硼的释放机理。实际上,氧化物在石英砂上负载之后覆盖了石英砂的大部分表面,但是铁氧化物并不是均匀分布在石英砂表面,而是主要负载在石英砂粗糙的表面或孔隙中。通过扫描电镜/X射线能谱分析,对铁氧化物,石英砂及负载铁氧化物的石英砂中的元素含量进行了分析,结果可以看出,只有Fe, Si和O的信号可以被检测到,B元素的信号没有在图片中显示出来。能谱仪定量分析结果发现,硼包被态针铁矿负载的石英砂中Fe元素的含量达到29.51%,明显高于针铁矿和硼吸附态针铁矿负载的石英砂中铁的百分比。8、通过砂培方式,研究了含硼氧化物随时间的变化硼的释放规律,以及氧化物中硼的释放对营养液中硼含量和油菜硼吸收的影响。结果发现,溶液中硼含量的变化规律与氧化物水溶态硼含量的变化规律非常相似,都是在0-2 d有一个急剧的变化,只是氧化物中硼的含量急剧下降,溶液中硼的含量急剧升高。氧化物中全硼含量的变化相对水溶态硼含量的变化要缓慢很多,没有观察到前两天的突降现象,只是在第6d到第8d有一个相对强烈的下降。氧化物对油菜硼吸收的影响呈现一个单峰曲线变化的规律。氧化物的加入对营养液的酸度起到很大影响。随着时间的变化营养液的酸化呈现一种缓解的趋势,两种氧化物对营养液pH的改变分别从最初的pH 5.02上升到实验结束时的7.97和7.73。为了更好的了解含硼氧化物中硼释放的规律,对含硼氧化物中的硼随时间的释放规律,含硼氧化物对上清液中硼的含量及pH的变化进行了曲线拟合,并做了相应的参数估计。结果发现Elovich方程最能反映氧化物中硼的释放过程,其次是抛物线方程和权函数方程。含硼氧化物对上清液中硼含量影响曲线拟合以零级方程,一级方程和权函数方程的拟合度最高,与含硼氧化物中硼的释放规律不一样,这可能是因为植物对硼吸收的缘故。含硼氧化物对上清液pH的影响与含硼氧化物中硼的释放规律相吻合,而且无论是氧化物中全硼的释放量还是水溶性硼的释放量均与溶液pH的增加量达到极显著的相关性,这说明氧化物中硼的释放量与溶液的酸度变化之间存在一种必然的内在联系。更多还原

【Abstract】 Different forms of boron-containing goethite and manganite were synthesized artificially. Through introducing them to the acid yellow-brown soil, the plant availability of the boron contained in the oxides and the effect of the boron-containing oxides on soil proprieties were observed, and the main results were shown as follows:1. The synthesis method of goethite, manganite and their boron-containing oxides were described and the properties of the oxides including surface areas, SEM photos and boron content of the oxides were discussed. The results showed that the changes of the specific surface area exhibited the same trends, that is oxide with occluded boron> ordinary oxide> oxide with adsorbed boron. And scanning electron microscopy results showed that the particles of goethite with occluded boron (i.e. oc-B-goethite) were more fine than ordinary goethite and goethite with adsorbed boron (i.e. ad-B-goethite), which is related to the combination form of boron on oxides.The boron content of the boron-containing oxides were extracted by different methods, it was found that the boron content of the goethite and manganite was greatly different, the boron content of boron-containing goethite is much higher than that of boron-containing manganite. And the boron content between oxides with adsorbed boron and oxides with occlude boron was also different, the boron content of ad-B-goethite was much higher than that of oc-B-goethtie, but the difference between manganite with adsorbed boron (i.e. ad-B-manganite) and manganite with occluded boron (i.e. oc-B-manganite) was relatively smaller.2. The effect of different amounts of the oxides on soil boron content, soil acidity, boron content of rape and rape biomass were investigated. The results showed that with the increasing of the boron-containing goethtie added into the soil, the boron content of the soil and rape was also increased. And when the amount of the boron-containing goethtie reached to 5 or 10 g kg-1 soil, the boron content of the soil and rape showed a dramatic rise phenomenon. But with the increasing of ordinary goethite added into the soil, the boron content of the soil and rape was reduced. The boron-containing manganite also increased the boron content of the soil and rape with the amount increasing.With the addition of boron-containing oxides increasing, the biomasses of rape showed a growing trend. When the amount of the oxides reached 3 g kg-1 soil, the biomasses of the rape reached maximum.The improvement of the soil acidity by the boron-containing iron and manganese oxides showed a clear dose relationship. The boron-containing iron oxides presented a stable increase on improving soil acidity with the amount increasing of the boron-containing goethtie, but it appeared a turning point of 2 g kg-1 soil addition of boron-containing manganite.Based on the above phenomenon, we think when the additive quantity of the oxides was 2-3 g kg-1 soil; it will be the best dose for our further research.3. Through the addition the boron-containing iron and manganese oxides into the soil, the influence of the boron-containing oxides on soil boron fractionation and the uptake of boron by rape was observed in a pot experiment. The results showed that the addition of the boron-containing oxides into the soil increased different forms of boron content including water soluble boron, nonspecifically adsorbed boron, specifically adsorbed boron and boron occluded in Fe and Al oxides. And the effect of boron-containing goethite on increasing soil boron content was greater than that of boron-containing manganite. The introduction of the boron-containing oxides was also increased the boron content of the shoot and root of rape.The simple linear regression analysis between different forms of the soil boron content and boron content of rape was calculated, results showed that the content of water soluble boron, nonspecifically adsorbed boron, specifically adsorbed boron and the boron occluded in amorphous Fe and Al oxides in the soil was all significantly correlated with the boron content of the shoot and root of rape. However, stepwise regression showed that only the water soluble boron and boron occluded in amorphous Fe and Al oxides in the soil was significantly correlated with the boron content of rape, which indicated that not only hot water-soluble boron can be regarded as a suitable index of plant available boron, the boron occluded in amorphous Fe and Al oxides also can play an important role in promoting the boron uptake by plants.4. The introduction of the oxides also enhanced soil available nutrient content and promoted rape seedling uptake of nutrients, and therefore promoted the rape growth. Regression analysis of nutrient content of the soil and rape seedling dry weight showed there was a significant positive correlation between the Ca and Mg content of the soil and rape seedling dry weight. Multiple regression results showed only Ca content in the soil significantly influenced rape seedling dry weight. It is surmised that the boron-containing oxides provided a pre-condition for the absorption of nutrients, i.e., an environment for plants to better utilize Ca and other elements during seedling growth and therefore promoted rape seedling dry weight.5. Rhizobox experiment was conducted to investigate the impact of boron-containing oxides on rhizosphere soil proprieties. The exchangeable acid and exchangeable Ca and exchangeable Mg all showed a positive rhizosphere effect; whereas the soil pH and exchangeable K in the rhizosphere soil was lower than that in the bulk soil. The addition of boron-containing oxides also stimulated soil enzyme activities, of which the catalase and polyphenol oxidase activity in rhizosphere soil was greater than that in the bulk soil, but the invertase and acid phosphatase activity in rhizosphere was lower than that in bulk soi.Rape seedling root morphology were analyzed using a WinRHIZO 2.0 Scanner Instrument, it showed that the rape roots growning on the boron-containing oxides treatments were more developed by increasing the total root length, root area, root tips, root volume and root surface area.6. A pot experiment was conducted to investigate the impact of boron-containing oxides on rape physiological proprieties. Results showed that the boron-containing improved the physiological adaptability of rape. Compared with the control, they all raised the chlorophyll and soluble sugar content of the leaves, as well as the root activity of rape. Also the addition of boron-containing oxides reduced malondialdehyde and proline accumulation in the leaves of rape.7. The release mechanism of the boron from the boron-containing oxides was investigated by loading the oxides onto quartz sand. Sand culture experiment was undertaken to investigate the release of the boron from the oxides clearly. It was found that the iron oxide in the quartz sand surface is not uniformly distributed, it mainly concentrated on the rough surfaces and pores of the quartz sand. The element content of the iron oxides, quartz sand and iron oxide coated quartz sand was investigated through scanning electron microscopy/X-ray energy analysis. The results showed that only Fe, Si and O signals can be detected, B element was not detected. EDS quantitative analysis found that the Fe content in oc-B-goethtie coated quartz sand reached 29.51%, which significantly higher than ordinary goethite or ad-B-goethite coated quartz sand.8. Sand culture experiment was conducted to investigate the boron release of the boron from boron-containing oxide and its effect on the boron content of the nutrient solution and rape. It was found that the changes of boron concentration in solution and the changes of water soluble boron content of the oxide is very similar, they all showed a drastic changes at 0-2 days, which was not same is the boron content of the oxides was sharply declined and the boron concentration in the solution was increased. The change of the total boron content of the oxide was relatively eased, it just showed a decline at 6-8 days. The influence of the oxides on the boron content of rape showed a single peak curve pattern. The oxides influenced the nutrient solution pH greatly, the pH of the solution in the two oxides treatment was changed from 5.02 at the initial of the experiment to7.97 and 7.73 at the end of the experiment, respectively.In order to better understand the release of boron from the boron-containing oxides, the curve fitting was conducted and the corresponding parameter was estimated. It was found that the highest correlation between boron release content of the boron-containing oxides and the changes of time is the Elovich equation; the second is parabolic diffusion equation and power function equation. Whereas, the changes of the boron content of the solution was not the same with the boron release content of the boron-containing oxide, which may be due to the absorption of the boron by rape seedling. The influence of the boron-containing oxides on solution pH was similar with the boron release content of the boron-containing oxides. Moreover, the total boron release content and the water soluble release content were all significantly correlated with the increase of the solution pH, which indicated that it must has exist an inherent relationship between the boron release content of the oxides and the changes of the solution pH.更多还原