RFLPs of chloroplast and mitochondrial DNA in wild soybean, Glycine soja, growing in China

RFLPs of chloroplast (cp) and mitochondrial (mt) DNA have been used to characterize the cytoplasmic genome of wild soybean, Glycine soja, growing in China. We have found from the RFLPs of that the cytoplasmic genomes of most Chinese wild soybeans have a combination of cpIII with mt-a or a combination of cpII with mt-b accompanied by mtIV or mtV according to our classification. CpII was not observed in combination with mt-a and cpIII was not observed in combination with mt-b. The regional distribution of these two types showed clines with opposite directions. The Yangtze River Valley had the greatest diversity in each of cp and two mt profiles detected in this study and the cytoplasmic genome combining these three profiles showed the highest degree of polymorphism in this region. The Yangtze River Valley may be a center of cytoplasmic diversity of wild soybean and may contain various genetic resources of soybean.     

Incongruence between RFLPs of chloroplast DNA and morphological classification in east Asian pear (Pyrus spp.)

Polymorphism of chloroplast DNA of 106 accessions of Pyrus (mainly east Asian accessions) was examined. Four haplotypes were observed with the combination of three independent restriction site mutations digested by EcoO109 I, Sal I, and Xba I, respectively. In the occidental pear accessions only the most plesiomorphic type was observed, whereas all four types appeared in the oriental pear accessions. This suggests that the oriental species of Pyrus and occidental ones may have evolved independently. The distribution of four haplotypes in the east Asian pear was quite incongruent with the species or infrageneric classification using mainly morphological characters. Considering the high crossability and much occurrence of suspected interspecific hybrids in wild populations, this disaccord is inferred to be the results of the hybridization and introgression between species.     

大豆鼓粒期对肥料氮的吸收与分配研究

采用15N分阶段标记的方法,研究了鼓粒期间大豆植株对氮素的同化吸收,尤其是肥料氮在各器官中的积累与分配。结果表明:1)5次标记试验期间积累的氮素总量为291.4 mg/plant,占标记试验Ⅴ结束时(鼓粒末期)大豆植株氮素积累总量的48.9%,说明鼓粒期间的氮素积累对于大豆氮素积累具有重要作用;2)从鼓粒始期到鼓粒末期,大豆植株氮素阶段积累量急剧降低,由标记试验Ⅰ的109.5 mg/plant下降到标记试验Ⅴ的19.6 mg/plant;3)鼓粒期大豆植株所吸收的氮素主要来自根瘤固氮,该部分氮占总同化量的67.4%,而肥料氮只占32.6%;4)根瘤固氮和肥料氮的同化量均随着鼓粒进程的推进而下降,分别由标记试验Ⅰ的67.5和42.0 mg/plant下降到标记试验Ⅴ的10.8和8.8 mg/plant;5)5次标记试验中,不同器官中肥料氮的积累量均表现出一致的规律性,为子粒叶片茎根系荚皮,并且分配到子粒中的肥料氮比例是逐渐增加的,由标记试验Ⅰ的27.9%增加到标记试验Ⅴ的85.0%。     

Effects of Rhizobium inoculation and magnesium application on growth and nodulation of soybean (Glycine max L.)

Abstract

Magnesium (Mg) deficiency is one of the major nutritional problems in tropic and subtropic areas, where the most soils are acidic. In this study, the effects of Mg application and Bradyrhizobium inoculation on growth, nodulation, symbiotic nitrogen (N) fixation as well as N nutrition status in soybean (Glycine max L.) were investigated in hydroponics under greenhouse conditions. With the increase of Mg up to 0.75?mM at low N and up to 0.5?mM at high N solutions, the dry weights of shoots, roots, and pod grain yield in soybean were increased, while further increase in Mg supply inhibited soybean growth. The availability of Mg was found to entail an improved uptake of N by plants and nodulation process in the root by Bradyrhizobium. Inoculation with rhizobial inoculants not only formed many nodules, but also increased soybean shoot, root biomass and yield, as well as plant N nutrient status.     

Effects of phosphorus amended low phosphorus soil on soybean (Glycine max L.) and wheat (Titicum aestivum L.) yield and phosphorus uptake

A major constraint for crop production on disturbed soils is phosphorus (P). A 2-year field study was conducted on a disturbed soil to evaluate broiler litter ash (BLA) as an inexpensive phosphorus fertilizer for soybean. BLA or super phosphate (SP) was applied at four rates and planted with soybean followed by wheat. At soybean growth stage R3, two plants from each plot were removed for tissue analysis. Soybean tissue P concentration distributions were in the order pods?>?leaves?>?stems?>?roots. At maturity, soybean grain and wheat tissue yields were not significantly affected by P source. Except for the high superphosphate rate for the second crop, P concentrations of soybean grain and wheat tissue were not significant between P source. In this study, BLA was as effective as SP for growth of soybean grain and wheat tissue, suggesting that BLA can be used as an inexpensive P fertilizer on low P disturbed soils.     

Impact of pyrochar and hydrochar on soybean (Glycine max L.) root nodulation and biological nitrogen fixation

The aim of this study was to identify effects of carbonized organic material (“biochar”) on soybean growth, root nodulation and biological nitrogen fixation, and to elucidate possible underlying mechanisms. Soybean (Glycine max L.) was grown in four arable soils amended with carbonized organic material produced from wood or maize as feedstocks, by pyrolysis (“pyrochar”) or hydrothermal carbonization (“hydrochar”). Nodulation by Bradyrhizobium , biological nitrogen fixation (BNF) assessed by ¹⁵N techniques, plant growth, nutrient uptake and changes in chemical soil properties after soil amendment were determined. Data were analyzed by means of a three way ANOVA on the factors soil, carbonization technique and feedstock. It turned out that soybean root nodulation and BNF was influenced by the carbonization technique used to prepare the soil amendment. Hydrochar, in average and across all soils, increased nodule dry matter and BNF by factors of 3.4 and 2.3, respectively, considerably more than pyrochar, which led to 1.8 and 1.2 fold increases, respectively. Nodule dry matter and BNF correlated positively with available soil sulfur and negatively with available soil nitrogen. Hydrochars provided more available sulfur than pyrochars, and hydrochars caused a decrease in nitrogen availability in the soil solution, thereby exerting a positive influence on nodulation and BNF. Pyrochar amendment increased soil pH but had no effect on nodulation and BNF. Plant growth was affected by the soil and by the feedstock used for the “biochar”, and increased slightly more in treatments with pyrochar and hydrochar made from maize, which was richer in nitrogen and potassium. The results show that carbonized organic materials, and specifically hydrochar, have the capacity to increase BNF in soils. We suggest that this enhancement in BNF in response to soil amendments with carbonized organic materials is due to an increase in available sulfur and a reduction of available soil nitrogen.     

Differences in numbers of nodules and lateral roots between soybean (Glycine max L. Merr.) cultivars,Kitamusume and Toyosuzu

Two cultivars of soybean (Glycine max L. Merr .), Kitamusume and Toyosuzu were grown with commercially-purchased granulated soil in a greenhouse. Kitamusume formed a larger number of nodules per g shoot dry weight and its nodules showed a smaller average diameter and average dry weight per nodule than Toyosuzu regardless of plant age or rhizobial strains (Bradyrhizobium japonicum (AI017, J5033, 646, J1B140), B. elkanii (USDA94), and Rhizobium fredii (MAFF210054)) inoculated at the rate of 10⁸-10⁹ cells per 3 L pot. These differences were observed in the nodules formed on both primary and lateral roots. With a lower inoculation dose of rhizobia (10² and 10⁵ cells per pot), Kitamusume formed a smaller number of larger nodules than Toyosuzu inoculated with 10⁸-10⁹ cells per pot. This result indicated that the number of nodules was the factor directly controlled by host, because the size of the nodules was not determined by the genetic background, but changed depending on the number of nodules formed. The number of the first order lateral roots of 21 d old Kitamusume was 1.49 times larger than that of Toyosuzu. The relationship between the number of nodules and the number of first order lateral roots of 14 cultivars showed a significant positive correlation. These results indicated that the formation of nodules and lateral roots may be similarly controlled by a certain factor in different cultivars.     

Growth characteristics,phytate contents,and coagulation properties of soymilk from a low-phytate Japanese soybean (Glycine max (L.) Merr.) line

The phytic acid (myo-inositol hexakisphosphate or InsP₆) content of seed crops is important to their nutritional quality. Since it represents 75?±?10% of the total seed phosphorus (P), phytic acid is also important regarding the management of P in agricultural production. A low-phytate F5 line, No. T-2-250-4-20, was selected from the progeny of a cross between the low-phytate soybean line CX1834 and the Japanese commercial cultivar Tanbakuro. This line and its parents were grown in a field nursery, and the growth characteristics, phytate accumulation, and processing suitability for tofu were evaluated. At full maturity, the weight of seeds per plant of line T-2-250-4-20 was 5.2- and 1.3-fold higher than that of CX1834 and Tanbakuro, respectively. The amount of phytate-phosphorus as a percentage of the total P content in seeds was 23% in line T-2-250-4-20-34, 30% in CX1834, and 69% in Tanbakuro. No significant difference was observed among the three cultivars/lines in their seed magnesium (Mg), potassium (K), crude protein, and sugar. However, the calcium (Ca), crude fat and ash contents in seeds of line T-2-250-4-20-34 and Tanbakuro was lowered compared to that of CX1834. The breaking stress of tofu was estimated employing a rheometer with a decreasing concentration of the coagulant magnesium chloride (MgCl₂), starting at 15.7?mmol?L^?1. In tofu made from Tanbakuro, the concentration of MgCl₂ required to achieve the maximum breaking stress was 12.6?mmol?L^?1; however, it was 9.5?mmol?L^?1 for tofu made from T-2-250-4-20-34 and CX1834. The tofu made from Tanbakuro was soft and broke at 6.3?mmol?L^?1 MgCl₂, but, in line T-2-250-4-20-34, harder tofu was made with lower MgCl₂ concentrations. No difference was observed among the cultivars/lines in the SDS-PAGE patterns of protein in soymilk. These results indicate that we have developed a low-phytate soybean with adequate productivity, and confirmed that tofu made from the low-phytate T-2-250-4-20-34 soybean becomes coagulated and harder at a lower MgCl₂ concentration than that from high-phytate soybean cultivars.     

Analysis of regulation site and manner of abundant nodulation in a soybean (Glycine max (L.) Merr.) cultivar,kitantusunte, using grafting techniques

To characterize the regulation site and manner of the abundant nodulation in the soybean (Glycine max (L.) Merr.) cv. Kitamusume, three grafting eperiments were carried out as follows: reciprocal wedge grafting and inter-cultivar approach grafting between Kitamusume and a normal nodulating cultivar, Toyosuzu, as well as wedge grafting of scions of the supernodulating mutant En6500 onto either Kitamusume or Toyosuzu rootstock. In the reciprocal wedge grafting, the number of nodules per shoot dry weight and average weight per nodule in the grafted plants were consistent with those exhibited by the genotype of their rootstocks. Approach grafting did not affect the number of nodules per shoot dry weight on either side of the inter-cultivar approachgrafted plant. Although grafting of the mutant scion resulted in the loss of the autoregulatory response from the roots of both cultivars, difference in the number of nodules per g shoot dry weight still remained between the two cultivars. These results suggested that the abundant nodulation in Kitamusume is controlled by the root in a non-systemic manner and is independent of the autoregulation mechanism.     

Inoculation with indigenous rhizobial isolates enhanced nodulation,growth, yield and protein content of soybean (Glycine max L.) at different agro-climatic regions in Ethiopia

Abstract

Soybean cultivation in Ethiopia is dominated by smallholder farmers who use little or no inputs, often resulting in low yields. The use of effective rhizobia strains was considered as an ecologically and environmentally sound approach for soybean production. Field experiments were conducted during 2015/16 cropping seasons at two different agro-climatic regions in Ethiopia to investigate the effectiveness of local soybean isolates for improving nodulation, growth, yield and quality of soybean. Ten treatments comprising of seven indigenous rhizobia isolates, one exotic strain, nitrogen fertilized treatment and uninoculated control were arranged in randomized complete block design in three replications. Results of the experiment revealed that nodule number and nodule dry weight significantly increased from nil in the uninoculated control to 14–34 and 110–521?mg plant^?1, respectively due to inoculation with different isolates. Furthermore, inoculation significantly increased shoot dry weight by 24–46%, shoot nitrogen concentration by 20–30%, shoot N content by 29–49%, plant height by 14–41%, pods per plant by 12–38%, seeds per pod by 7–19%, thousand seed weight by 15–24%, grain yield by 22–115% and protein content by 7–39% compared with the uninoculated control. Generally, isolates Jm-1-Bo, As-5-Aw, Bk-3-Aw, Cw-6-Aw and MAR 1495 performed better than the others in most yield parameters at both locations of which Jm-1-Bo and As-5-Aw were the local isolates performing best irrespective of location, and were superior to the effective exotic standard strain. Therefore, isolates Jm-1-Bo, As-5-Aw and Bk-3-Aw could be utilized as candidates for inoculant production at large scale in areas with similar agroecology.     

缺磷胁迫下草甘膦对抗草甘膦大豆幼苗光合作用和叶绿素荧光参数的影响1

为探明缺磷胁迫下草甘膦对抗草甘膦大豆（RR1）幼苗叶片光合作用和叶绿素荧光参数的影响,采用溶液培养方法,在大豆长出真叶时进行缺磷胁迫,第二复叶完全展开时进行草甘膦处理,5d后测定各生理指标。结果表明, 相对于正常供磷条件的清水处理,缺磷胁迫下4.98 mL/L草甘膦处理的大豆叶片净光合速率（Pn）、气孔导度（Gs）、胞间CO2浓度（Ci）、最大荧光（Fm）、PSⅡ最大光化学效率（Fv/Fm）、PSⅡ的有效量子产量［Y(Ⅱ)］、PSⅡ非调节性能量耗散的量子产量［Y(NO)］、最大电子传递速率（ETRmax）和半饱和光强（Ik）均呈下降趋势。而气孔限制值（Ls）、叶绿素a（Chl a）、叶绿素b（Chl b）、叶绿素a/b（Chl a/b）、类胡萝卜素（Car）、总叶绿素（Chl）含量和PSⅡ调节性能量耗散的量子产量［Y(NPQ)］均呈升高趋势。说明缺磷胁迫条件下喷施草甘膦显著降低了抗草甘膦大豆的光合速率。缺磷引起的气孔因素可能是导致RR大豆光合速率下降的主要原因,而光合速率的下降导致其PSⅡ反应中心的开放程度降低,活性减弱,参与CO2固定的电子较少,光化学效率较低。     

Positive correlation between the number of root nodule primordia and seed sugar secretion in soybean (Glycine max L.) seedlings inoculated with a low density of Bradyrhizobium japonicum

Sufficient rhizobium population in the rhizosphere of legume seedlings is required for early and enough setting of root nodules. Potential of seed and seedling root exudates for proliferation of Bradyrhizobium japonicum PNT119 was evaluated in the soybean cvs. Enrei and Tachinagaha. In both cultivars, seed exudates showed a higher potential than root exudates. In the seed exudates, a low-molecular high-polarity fraction including sugars and amino acids showed a higher potential than both high-molecular fraction and low-molecular low-polarity fraction. The correlations between the sugar or amino acid contents of seed exudates and the number of root nodule primordia at 7 d after sowing were investigated among 12 soybean cultivars. When seeds were inoculated with a low rhizobium density, a high correlation coefficient was detected between them. However, there was no positive correlation in the plants inoculated with a high rhizobium density. These results suggest that the amount of low molecular substances in the seed exudates determines the number of root nodule primordia through rhizobium proliferation around seed and young roots when the rhizobium density is the limiting factor. The genetic trait relating to seed coat secretion should be considered as a possible key factor contributing to adequate root nodulation in soybean seedlings cultivated in fields with a low rhizobium density.     

铝胁迫下大豆根系脱落酸累积与柠檬酸分泌的关系研究

为探讨铝(Al)胁迫条件下脱落酸(ABA)调控植物根系有机酸分泌的机制,进行了ABA与Al诱导大豆根系柠檬酸分泌的关系试验。结果表明:1)外源ABA和ABA合成抑制剂fluridone分别提高和降低了Al诱导的大豆根尖ABA含量的增加,但对根系柠檬酸分泌量均无影响,ABA对根系内源柠檬酸含量和柠檬酸合成酶的活性也没有影响;2)分根试验表明,与Al直接接触的根部(Part A)内源ABA含量发生变化,且有柠檬酸的分泌,而不与Al直接接触的根部(Part B)内源ABA含量也发生变化,但没有柠檬酸分泌;3)Al胁迫下,大豆耐Al基因型柠檬酸分泌量远高于敏感基因型,但二者的内源ABA含量却没有差异;4)30μmol AlCl3处理,在0~12 h柠檬酸分泌速率和内源ABA含量随Al处理时间增加而增加,去除Al胁迫时(12~18 h),柠檬酸分泌速率继续增加,但内源ABA含量则迅速下降。综合以上结果,推测ABA不是通过提高Al诱导柠檬酸分泌来调控大豆耐Al性。     

Influence of lime and phosphorus on soybean (Glycine max (L.) Merrill) yield,leaf and seed composition on a paleudult soil

Abstract

This research was undertaken on a paleudult soil in southern Brazil, 30° south latitude, to quantify lime and P effect upon soybean (Glycine max (L.) Merrill). A lime x P factorial experience with lime treatments of 0, 0.5, 1, and 2 times SMP interpretation to pH 6.5, and 0, 44, 88, 132, and 176 kg P/ha with 3 replications were installed. The experiment was conducted for 2 years (1973–74, 1974–75), with leaf‐N, P, and K; yield; seed‐N, P, and K; Bray P₂ (0.03N NH₄F + 0.1N HC1) avail‐able‐P and soil pH measurements completed each year. Data was evaluated with linear, quadratic, logarithmic, polynomial, segmented line, and multiple regression using the coefficient of determination as goodness of fit.

The best model fit between P treatment and Bray P₂ available‐P was a quadratic equation; the model between relative yield and Bray P_2‐P with 54% of the relative yield attributed to Bray P₂ available‐P, a sigmented line. This model indicated point of maximum yield (91% relative yield) was obtained at 7.4 ppm‐P, with no increase in relative yield with increasing levels of soil available‐P. To calculate the P fertilizer necessary to increase available soil‐P to the level of maximum yield of equation Y_p = [1639(7.4 ‐ x_s)]^1/2, where Y_p = kg P/ha fertilizer needed; and x_s = initial Bray P₂ soil available‐P in ppm's. The lime effect upon soil pH was best described as a linear relationship. Yield increase with lime at this site was not significant at the 5% level.

The leaf‐N, P, and K increased significantly with soil available‐P levels. A second degree polynomial with logarithmic function best defined these relationships. The calculated DRIS indices and sum proved useful to evaluate the plant‐N, P, and K balance of each treatment.

Only seed‐P level was directly related to soil available‐P. Both seed‐N and seed‐K were highly correlated with indirect effects of soil available‐P levels.

Results from this study suggest the segmented line model would best interpret soybean yield response to Bray P₂ available‐P for this soil. To obtain maximum yield using this model rather than the second degree polynomial would require less fertilizer P. Foliar analyses interpretation confirmed adequate plant‐P level would be supplied for maximum yield at this level of fertilization.     

Effects of cropping systems,maize residues application and N fertilization on promiscuous soybean yields and diversity of native rhizobia in Central Kenya

Agriculture intensification has resulted in severe soil nutrient depletion in Africa. Alternative agricultural practices have been promoted to reduce the use of expensive mineral fertilizers and to restore and sustain soil fertility. The use of mineral fertilizer combined with organic inputs (such as crop residues) and different cropping systems (cereal–legume association or rotation) have been particularly promising. Impacts of these agricultural practices on soil communities have been widely studied, yet little is known on the effect on more specific groups such as rhizobia. A field trial was set up in Chuka (Kenya) to assess the impact of different cropping systems (maize and soybean in intercropping, rotation or monocropping) combined with N fertilization and residues application on the genetic diversity of promiscuous soybean rhizobia during two seasons. Soybean yields were severely reduced by moisture stress and the association with maize compared to mono-legume and rotation systems. Nodulation was generally low but was positively affected by residues application. Diversity of native rhizobia was very low (Shannon indices H′ < 0.8) across the experiment and was not affected by the treatments. Only 5 IGS profiles were obtained after RFLP analysis and all isolated rhizobia were identified as Bradyrhizobium elkanii. The distribution of the different IGS groups within the experiment was more affected by season and residues application than by cropping system and nitrogen fertilizer application. These results suggest a limited population and a low diversity of indigenous rhizobia, and emphasize the need of alternative managements to increase and sustain soybean yields in Central Kenya.     

Molecular phylogeny of the apterygotan insects based on nuclear and mitochondrial genes

Basal hexapodan orders (Apterygota) are traditionally divided in two well defined taxonomic groups, Entognatha and Ectognatha. Entognathy (the enclosed mouthparts condition) is considered the most distinctive character joining the Ellipura (Protura+ Collembola) with the order Diplura, whereas the presence of exposed mouthparts (ectognathy) is the feature shared by Microcoryphia and Zygentoma with the pterygote insects. In spite of the growing interest for the evolutionary history of the Apterygota, there is no complete agreement among the general phylogenetic hypotheses based on the study of morphological characters. In this study we analyzed the DNA sequence of segments of the nuclear Elongation Factor-1α(EF-1α) and of the mitochondrial 12S rRNA genes, and used different methods of phylogenetic reconstruction. The 12S gene seems to be more suited than the EF-1α to resolve some of the most outstanding systematic disputes, whereas the lack of resolution at the deeper nodes does not allow to assess the phylogenetic relationships within Microcoryphia and between ectognathan orders. We have obtained a fairly high support for the monophyly of the orders Diplura and Zygentoma. In the 12S analysis, the Ellipura and the Entognatha form monophyletic assemblages. In addition, the study of the distribution of introns in the EF-1α suggests a relationship between Collembola and Diplura.     

Estimation of the root colonization of soybean by an arbuscular mycorrhizal fungus,Gigaspora rosea,based on specific fatty acid profiles

Root colonization by arbuscular mycorrhizal (AM) fungi has traditionally been analyzed by microscopy. However, this method is time consuming and it is often difficult to distinguish between AM and non-AM fungi. In this study, we analyzed the fatty acid profiles in soybean roots colonized by AM fungi to determine if specific fatty acids derived from AM fungi can be used as markers for the intensity of the AM fungal colonization. The wild-type Enrei and hypernodulating Kanto100 soybean cultivars were inoculated with an AM fungus (Gigaspora rosea) alone or with Bradyrhizobium diazoefficiens, which nodulates soybean roots. Fatty acids 20:1ω9, 20:4ω6, and 20:5ω3 were specifically detected in the lateral roots of AM fungus-inoculated and dual-inoculated soybean plants. In the second lateral roots, the percentage of AM-specific fatty acids (i.e., 20:1ω9, 20:4ω6, and 20:5ω3) derived from AM fungi was closely correlated with the intensity of the AM fungal colonization. We propose that the AM-specific fatty acids represent useful markers for estimating the degree of AM fungal colonization. The percentage of AM-specific fatty acids was more than twofold higher in the second lateral roots than in the first lateral roots. Thus, the degree of AM fungal colonization is probably twofold higher in the second lateral roots than in the first lateral roots.     

Effect of some fungicide seed treatments on the survival of Bradyrhizobium japonicum and on the nodulation and yield of soybean [Glycine max. (L) Merr.]

Several commercial fungicide seed treatments were evaluated for their possible effect on the survival of Bradyrhizobium japonicum on seeds and on the nodulation and yield of soybeans in a greenhouse and a field experiment. quinolate Pro (carbendazim and oxine copper), Vitavax 200FF (carboxin and thiram), and Monceren (pencycuron) had a small effect or no effect on the survival of B. japonicum and on the nodulation and yield of soybeans. They can thus be considered compatible with soybean seed inoculation. Germipro UFB (carbendazim and iprodione), Apron 35J (metalaxyl), and Tachigaren (hymexazol) decreased B. japonicum survival and the nodulation and yield of soybeans and thus cannot be considered compatible with soybean seed inoculation.