低磷土壤条件下菜豆根构型的适应性变化与磷效率

利用分层隔网式土壤盆栽系统结合计算机图像分析技术 ,以基根根长、根表面积等在生长介质各层中的相对分布量为指标 ,定量测定菜豆 (PhaseolusvulgarisL .)根构型在低磷胁迫下的适应性变化及其与磷效率的关系。研究结果表明 :在低磷条件下 ,菜豆根部生物量减少 ,根系总长度变短 ,根总表面积减少 ,磷高效基因型G1 9833、G1 9839的基根根长、根表面积降低较少且在介质表层的相对分布量增加 ;而磷低效品种DOR364的根长、根表面积降低较多而在表层的相对分布量减少 ,说明菜豆根构型特征对低磷胁迫具有适应性变化 ,磷高效基因型在低磷条件下能保持一定的根长、根表面积 ,且根系向地性减弱而形成浅根式的根构型 ,使根系内竞争减少 ,从而能够利用更多的土壤磷     

菜豆叶片特征与磷效率关系初探

大量研究表明,不同菜豆品种对低磷土壤的忍耐能力存在基因型差异[1～7].有研究发现菜豆有两个独立的基因库(MA和AN),其中AN基因库的大粒种菜豆颇具有高磷效率潜力,但对于其耐低磷的形态和生理生化基础的研究还不多.     

低磷胁迫下菜豆根构型性状的QTL定位

在田间和温室筛选的基础上,选取根构型对低磷适应性变化和磷效率均具有显著差异的菜豆基因型ＤＯＲ３６４和Ｇ１９８３３为亲本材料,发展了Ｆ５代重组自交系遗传群体,以基部侧根（以下简称基根）在生长介质中各层的分布、浅根数目以及基根平均生长角度等根构型参数为指标,分析了根构型性状对低磷胁迫适应性变化的遗传特性,发现该性状是一个典型的数量遗传性状。我们进一步应用分子标记技术（ＲＦＬＰ、ＲＡＰＤ、ＡＦＬＰ）对控     

黄土高原旱地长期轮作与施肥土壤微生物量磷的变化

土壤微生物量是土壤中植物有效养分的储备库,在土壤肥力和植物营养中具有重要作用[1].我国北方石灰性土壤微生物量磷为P 12.4～15.5μg/g[2],南方红壤的微生物量磷为P 12.2～31.5μg/g[3].Brookes[4]根据土壤微生物量的周转速率计算英国土壤年周转通量,发现微生物量磷周转足以提供草地所需要的磷素,即使在含量比较低的耕地土壤,微生物量磷也能够提供70%左右作物生长发育所需要的磷.可见,微生物量磷是植物非常重要的磷素营养来源.     

高温焚烧对秸秆灰渣磷、钾养分变化的影响

生物质能是我国仅次于煤炭、石油和天然气的第4位能源资源,是可再生能源的一部分,在能源系统中占有重要地位[1]。农作物秸秆作为一种生物质能,也是我国广大农村中重要能源之一[2]。如何合理利用秸秆这一类生物质能已成为研究的热点[3]。自1988年丹麦建成世界第一座秸秆发电厂后,秸秆发电已成为秸秆能源化利用的新途径[4],目前,秸秆发电技术在发达国家如美国、欧洲、日本等已广泛采用。受世界能源危机的影响,近两年,我国许多省市引进国外技术,开始陆续上马秸秆发电建设项目。然而,秸秆发电过程中,会产生约占秸秆量15%左右的灰渣,由于发电厂秸…     

北方春大豆磷高效基因型的筛选

The selection of spring soybean genotypes with highphosphorus efficiency in Northern ChinaDING Yu-chuan1,2,CHEN Ming-chang1,CHENG Bin1,LI Li-jun1,ZHANG Hai-sheng3(1 Soil and Fertilizer Inst.,Shanxi AAS,Shanxi Key Lab.of Soil Envir.and Nutrient Resou.,Taiy…     

Biofortification of common bean as a complementary approach to addressing zinc deficiency in South Africans

Deficiencies of vitamin A, iodine, iron and zinc (Zn) in humans are caused partly by the consumption of food that has insufficient quantities of these. Their deficiency has a negative impact on the health, wellbeing, social and economic status of human beings. A national survey conducted in 2012 identified deficiencies of vitamin A, Fe, and Zn among other nutrients in South Africans and regarded the deficiencies of vitamin A and Fe as a moderate but not Zn. This review discusses causes of Zn prevalence in low-income South Africans and that it is largely caused by the low content of Zn in their diets. Initiatives to reduce Zn deficiency include fortification of wheat products and maize meal which has failed to address it successfully. Weaknesses of fortification include high cost of fortified food products to low-income populations, poor regulation in ensuring compliance in fortification, non-fortification of sorghum meal, and leaching of fortified nutrients during processing. This review suggests Zn-biofortification of locally-preferred common bean cultivars as an alternative strategy to compliment fortification. The review also discusses advantages of adopting biofortified Nutritional Andean common beans. Furthermore, the review suggests initiatives including evaluation of the common bean genotypes’ adaptation to different agro-ecologies.     

Proton release by nodulated roots varies among common bean genotypes (Phaseolus vulgaris) under phosphorus deficiency

Responses of proton release to phosphorus (P) availability by nodulated roots of common bean (Phaseolus vulgaris L.) were investigated for lines BAT 477 and CocoT, inoculated with Rhizobium tropici CIAT 899 in hydroaeroponic culture under glasshouse conditions. Phosphorus was supplied as KH₂PO₄ at 15 and 60 μmol plant^–1 week^–1 (15P and 60P). Proton release was higher for BAT 477 than for CocoT under both P supplies. However, it was higher for 60P than 15P, whatever the line. The ratio of proton release per unit biomass of nodulated root was higher for BAT 477 than for CocoT, independent of P deficiency. Proton release was correlated with the nodulated‐root respiration for both genotypes and with the nodule respiration linked with nitrogen fixation for CocoT. Thus, the nodulation was more limited by 15P than root and shoot growth and more in CocoT than in BAT 477. It is concluded that independent of symbiotic N₂ fixation, proton release was higher in BAT 477 than in CocoT and that the nodulated legume releases a substantial amount of protons into its rhizosphere that is correlated with its nitrogen fixation that eventually depends upon the nodule permeability to O₂ diffusion.     

铝胁迫下植物根尖细胞壁组成物质变化抑制根伸长的生理机制研究

根伸长受抑制是植物受铝毒害的主要症状,铝诱导的细胞壁组成物质的变化是其主要原因。本文主要对铝胁迫下植物根尖细胞壁组成物质如木质素、 胼胝质、 纤维素、 半纤维素、 果胶、 细胞壁多糖蛋白及相关代谢酶类在铝胁迫下的变化对根伸长的影响及生理机理的研究进展进行了综述,明确了铝胁迫诱导的植物根尖细胞壁组成物质含量、 比例及结构的变化导致细胞壁刚性降低,从而抑制细胞伸长,最终抑制根伸长。本文还指出,鉴于缺乏对同一植物甚至同一个种类的植物根尖细胞壁各主要组成物质铝胁迫下变化的系统研究,不能对造成该植物根伸长受抑制的原因做出全面合理的解释,所以今后应侧重于铝胁迫下各细胞壁组分变化在抑制根伸长中的贡献率的研究,尤其要针对主要粮食作物进行系统研究,以有效解决铝胁迫造成的产质量降低。     

Nodulation and growth of common bean (Phaseolus vulgaris) under water deficiency

Three experiments were conducted in order to investigate the effect of water deficiency on nodulation, rhizobial diversity and growth of common bean. In the first experiment, the effect of water deficiency was studied on two soil samples under glasshouse conditions. A significant decrease in nodulation and shoot dry weight production was observed. The molecular characterization of the root nodule isolates by PCR-RFLP of 16S rRNA and nodC genes showed that the nodulation by Rhizobium etli was severely inhibited. The in vitro analysis of salt tolerance indicated that drought stress favoured nodulation by salt-tolerant strains. In the second experiment, the effect of water deficiency was studied on sterilized sand using Rhizobium tropici CIAT899^T and Ensifer meliloti bv. mediterranense 4H41 as inoculants. The results showed that strain 4H41, which is the more salt tolerant, was more competitive and more effective under water deficiency than strain CIAT899^T. In the third experiment, the strain 4H41 was used to inoculate four fields. A significant increase in nodule number, shoot dry weight and grain yield was observed even in the non-irrigated soils. This work constitutes the first report of a strain enhancing the growth and the grain yield of common bean under water deficiency.     

Growth attributes,xylem sap composition,and photosynthesis in common bean as affected by nitrogen and phosphorus deficiency

The effects of nitrogen (N‐) and phosphorus (P‐) deficiency, isolatedly or in combination, on growth, nitrogenous fraction, and inorganic phosphate in xylem exudade, and photosynthesis of common bean (Phaseolus vulgaris L. cv. Negrito) were investigated. Plants were grown in nutrient solution adjusted daily to pH 5.5 and aerated continuously. Ten days after emergence mineral deficiency was imposed. Plants were then supplied with high N (7.5 mol m^‐3) or low N (0.5 mol m^‐3), and also with high P (0.5 mol m^‐3) or low P (0.005 mol m^‐3). All sampling and measurements were made 28 days after emergence. N‐ or P‐deprivation brought about large decreases in total leaf area by inhibiting the emergence of new leaves and primarily the expansion of the leaves. The specific leaf area did not change under N‐ but decreased under P‐limitation. The decreased shoot to root ratio in all deficiency treatments was a consequence of a lowering mass of above‐ground organs, especially of leaves.

The content of chlorophylls declined significantly only under N‐deficiency alone; carotenoids declined under both N‐ and combined N‐ and P‐limitation. No alteration in amino acid concentration in xylem exudate occurred in plants experiencing N‐starvation, while ureides increased by 79%, and nitrate and inorganic phosphate decreased greatly. Under P‐deprivation, amino acids and nitrate in xylem sap dropped by about half; ureides were held relatively constant, and phosphate was severely depressed. Total upward translocation of N through xylem was estimated to be about 16% higher in N‐deficient plants than in plants without mineral limitation, but leaf N levels in the former were lower as compared to control plants. The net carbon (C) assimilation decreased similarly regardless of the imposed deficiency treatment. Such a decrease was mainly determined by non‐stomatal factors. In general, no additive effect between N‐ and P‐limitation on any of measured parameters was observed.     

13N-nitrate uptake sites and rhizobium-infectible region in a single root of common bean and soybean

The positron emitting tracer-imaging system (PETIS) was used to determine whether it was possible to obtain on image of ¹³N-distribution in common bean in which a single root was fed with a liquid medium containing nitrate at different concentrations with different ¹³N specific activities. The distribution of the images of the ¹³N atoms in the root could be obtained over a wide range of nitrate concentrations and ¹³N specific activities in the medium. As for nitrate stress on leguminous root nodulation, the positional relationship between the nitrate uptake sites and root hair just elongating area, where rhizobia capably initiate their infection, was studied in common bean and soybean. PETIS gave direct evidence that single roots of both common bean and soybean showed one or two dense ¹³N-distribution areas after 2 min pulse-feeding of ¹³N0₃ ^-. These areas remained stable over 30 min, and the first dense site, which was common in all the examined roots, extended over ca. 1 cm above the root apex. Microscopic observation revealed that this area covered both sites of rhizobium infection and of early nodule development in a common bean and soybean single root.     

低氮胁迫下水稻根系的发生及生长素的响应

采用水培实验,研究了5个氮(N)浓度下(0.01～5 mmol L-1)水稻的生物量、体内氮浓度、根系发育、体内生长素浓度以及生长素外流蛋白OsPIN家族基因的表达情况。结果表明,与正常供氮水平(2.5mmol L-1)相比,低氮(0.01 mmol L-1)胁迫下水稻根冠比增加28%,地上部全氮浓度降低约20%,根系全氮浓度降低约33%,种子根长度增加25%,种子根上的侧根密度降低26%,倒一叶中的生长素含量增加140%,而根茎结合处和根系的生长素浓度分别下降22%和60%;RT-PCR的结果表明,低氮(0.01 mmol L-1)胁迫下水稻根系中OsPIN1a-b、OsPIN2、OsPIN5a-b和OsPIN9基因表达显著下调;而外源生长素α-萘乙酸(NAA)和生长素极性运输抑制剂1-萘氨甲酰苯甲酸(NPA)的施加均能影响到水稻种子根长和种子根上的侧根密度。由此推论,低氮胁迫下水稻体内生长素从倒一叶到根系极性运输减少是水稻根系对低氮胁迫响应的生理机制之一。