Eco-physiology of Primula farinosa Linn,: and some allied species

Ecological and physiological comparisons were made mainly between two populations of Primula farinosa Linn, from northern England and some of their closely related arctic-alpine species:- P. frondosa, P. darialica, P. halleri, P. laurentiana, P. modesta, P. scotica, P. scandinavica, and P. stricta, which have contrasting habitats and natural distribution. The germination of primulas showed a negative or neutral response to the density of seeds sown. They also showed intrinsic seed-dormancy which can be overcome by chilling treatment. Most of the species tested had significantly higher percentage germination in a diurnally fluctuating temperature regime than at 15ºC constant temperature. The results from analyses of leaf characteristics showed significant variation between species studied. Significant correlations were found between chromosome numbers of the species studied and some leaf characteristics, e.g. cell size, stomatal index. Plant growth analyses were investigated along an altitudmal gradient in the north of England. Both vegetative and reproductive growth was clearly affected by microclimate. The primulas showed more sensitive responses to drought than frost as regards to their survival. They responded to water stress by accumulating proline as well as increasing their total protein contents. Photosynthesis measurements showed optimum temperature for O(_2) evolution at warm temperatures of 20-25ºC. The difference in physiological performances of the primulas is discussed in relation to their leaf characteristics, ploidy levels and habitats of origin. This study demonstrates clearly that the two populations of P. farinosa differed in a number of morphological and physiological characteristics; some of which could make it possible for the different races to occupy different ecological habitats

Acute effect of Kineslo Taping on Knee Joint Blornechanics during Drop Vertical Jump In Anterlor Cruclate ligament-Deflcient Knee

Kinesio tape (KT), an elastic therapeutic tape, is useful for prevention and treatment of sport injury, but their efficacies remain unclear on mechanical change. The purpose of this study was to analyze the acute effect of KT on knee joint biomechanics during drop vertical jump in individuals with ACL injuries. Seven participants with partial ACL tears performed drop vertical jump (DVJ) with and without ACL KT taping technique. Peak knee joint angles and moments, and knee joint angle at initial contact were obtained from 3D motion analysis system. Paired t-test did not reveal significant differences of knee joint biomechanics between the 2 conditions. In conclusion, KT did not produce any biomechanical change in participants with partial ACL tears

Growth, symbiotic, and proteomics studies of soybean Bradyrhizobium in response to adaptive acid tolerance

Bradyrhizobial inoculated soybean often performs poorly on acid-soil because of the acid sensitivity of their associated root nodule bacteria. Acid tolerance in rhizobia has been considered as a key phenotypic characteristic in that it enables the bacteria to perform well under the restrictive conditions of excessive acidity. Since bacteria could develop acid tolerance to a more acid condition by using adaptive acid tolerance response (ATR), it is interesting to investigate whether bradyrhizobia could have this response and what proteins are involved in ATR. Bradyrhizobium sp. DASA01007 was selected for this study based on its ATR ability and symbiosis efficiency with soybean under acid condition. To establish an ATR in bradyrhizobia, late log phase culture of cell grown in mild acid condition was subsequently used as inoculum to more acid conditions. The 2D-gel and proteomic analyses were used to investigate the proteins response during ATR compared with non-adaptive conditions. The 29 identified proteins were grouped into 8 categories based on category orthologous group (COG) and one group of unknown categories. Hypothetical protein, transport and binding proteins, and translation protein were up-regulated at pH 4.5N (non-adaptive condition). While up-regulated proteins found during growth at pH 4.5A (adaptive condition) consisted of proteins in cellular processes, translation, energy metabolism, regulatory functions, interconversions and salvage of nucleosides and nucleotides, and conserved hypothetical proteins group. However, transport and binding proteins were absent in adaptive condition. At pH 5.5A, proteins involved in cellular processes were also detected. Several proteins overproduced in adaptive condition may be involved in ATR of bradyrhizobia. An importance of ATR in root nodule bacteria would support a better chance of survival in low pH soils than those conventionally grown in neutral pH. These results suggest that the use of ATR condition could provide an improvement in the production of inoculants.Keywords: Adaptive acid tolerance, Bradyrhizobium, Soybean, 2D-gel electrophoresi

Characterization and monitoring of selected rhizobial strains isolated from tree legumes in Thailand

Tree legume rhizobia were isolated from five tree legumes; Acacia auriculaformis Cunn., A. mangium Willd., Milletia leucantha Kurz., Pterocarpus indicus Willd., and Xylia xylocarpa Taub. grown in Thailand.Forty four highly effective rhizobial strains were selected on the basis of nitrogenase activity, number of nodules and plant biomass. The selected strains were characterized in both terms of physiology andgenetics. Most of the strains are slow grower and able to nodulate cowpea rather than soybean. In addition, IAA production could be detected only from few strains. When almost complete 16S rRNAsequences were analysed, the results indicated that most of the selected strains most likely belong to Bradyrhizobium elkanii and Bradyrhizobium sp. except strains AA67 and PT59 which most likely belong to B. japonicum. The nodule occupancy of selected strains in forest soil condition was investigated by using GUS reporter gene. The nodule occupancy is in the range of 63 - 100%. This suggests theappropriate strains should be produced as inoculum for further application in reforestation programmes in Thailand

A simple and highly efficient protocol for somatic embryogenesis and plant regeneration from proembryonic mass suspension culture in 'Autumn Royal Seedless'

Research Not

Co-inoculation effects of Bradyrhizobium japonicum and Azospirillum sp. on competitive nodulation and rhizosphere eubacterial community structures of soybean under rhizobia-established soil conditions

Bradyrhizobial inoculants used for soybean seed inoculation to maximize the benefit of N2-fixation should include bradyrhizobial strain with high N2-fixation rates and ability to compete with the indigenous rhizobial populations. In this study, co-inoculation of plant growth promoting rhizobacteria (PGPR) Azospirillum sp. with either of Bradyrhizobium japonicum CB 1809 or USDA 110 increased shoot and root dry weight of soybean over non-inoculated control under pot condition with no indigenous soybean nodulating bradyrhizobia. Moreover, competition for nodulation and the effects on rhizosphere soil eubacterial community structures by using single or co-inoculation of B. japonicum and Azospirillum sp. under rhizobia-established Myanmar and Thailand soils were investigated. By inoculation of gus-marked USDA 110 singly or its co-inoculation gave 93.21 to 94.75% and 74.21 to 100% in nodule occupancy, and 23.50 to 41.95% and 50.37 to 73.24% promotion in biomass dry weight over non-inoculated control in Myanmar and Thailand soil samples, respectively. Each of all the tested inoculum levels, that is 106, 107 and 108 cfu/ml of Azospirillum sp. enhanced nodulation in combination with USDA 110 with a corresponding increase in 73.8, 62.25 and 95.34%; and 51.52, 62.38 and 79.46% over non-inoculated control, respectively in Myanmar and Thailand soil, respectively. In addition, soybean rhizosphere soil eubacterial community structures were not shifted by bacterial inoculation. Therefore, Azospirillum sp. could be used in co-inoculant production with B. japonicum for soybean.Keywords: Bradyrhizobium, plant growth promoting rhizobacteria (PGPR), soybean, co-inoculation, competition, rhizosphere eubacterial community structureAfrican Journal of Biotechnology Vol. 12(20), pp. 2850-286

Selection and evaluation of Bradyrhizobium inoculum for peanut, Arachis hypogea production in the Lao People’s Democratic Republic

The interaction between leguminous plants and Bradyrhizobium is limited, known as host specificity. Therefore, the selection of an appropriate Bradyrhizobia for use as biofertilizer inoculum for legumes is necessary. The Arachis hypogea L. is the most popular legume produced in the Lao People's Democratic Republic (PDR). Therefore, this research aimed to obtain the appropriate Bradyrhizobia that provides high efficiency in A. hypogea production in the Lao PDR. The 14 isolates were obtained from root nodules of A. hypogea L. trapped with Lao PDR soil samples. Three were the top isolates PMVTL-01, SMVTL-02, and BLXBL-03 showing high efficiency for peanut growth promotion. Strains PMVTL-01 and SMVTL-02 were closely related to the Bradyrhizobium geno sp. SA-3 Rp7b and B. zhanjiangense, respectively, whilst strain BLXBL-03 was closely related to Bradyrhizobium sp. CCBAU51745 and B. manausense BR3351. The competitiveness of these strains with Bradyrhizobium sp. SUTN9-2::GFP was analyzed, and only Bradyrhizobium sp. SMVTL-02 performed a number of occupied nodules higher than SUTN9-2::GFP. In addition, the competitiveness of the selected strain Bradyrhizobium sp. SMVTL-02 in a soil sample from the Lao PDR in the pot level was employed by tagging the SMVTL-02 with the DsRed gene. The results demonstrated that the DsRed-expressing tagged strain showed higher nodule occupancy than indigenous strains. Moreover, the results of the acetylene reduction assay (ARA), nodule number, nodule dry weight, and total plant dry weight from the pot experiment that inoculated with the SMVTL-02::DsRed were presented as having high potential to promote peanut growth as compared to non-inoculation. Thus, Bradyrhizobium sp. SMVTL-02 could be considered a potential biofertilizer inoculum for A. hypogea production in the Lao PDR

Type 3 Secretion System (T3SS) of Bradyrhizobium sp. DOA9 and Its Roles in Legume Symbiosis and Rice Endophytic Association.

The Bradyrhizobium sp. DOA9 strain isolated from a paddy field has the ability to nodulate a wide spectrum of legumes. Unlike other bradyrhizobia, this strain has a symbiotic plasmid harboring nod, nif, and type 3 secretion system (T3SS) genes. This T3SS cluster contains all the genes necessary for the formation of the secretory apparatus and the transcriptional activator (TtsI), which is preceded by a nod-box motif. An in silico search predicted 14 effectors putatively translocated by this T3SS machinery. In this study, we explored the role of the T3SS in the symbiotic performance of DOA9 by evaluating the ability of a T3SS mutant (ΩrhcN) to nodulate legumes belonging to Dalbergioid, Millettioid, and Genistoid tribes. Among the nine species tested, four (Arachis hypogea, Vigna radiata, Crotalaria juncea, and Macroptilium atropurpureum) responded positively to the rhcN mutation (ranging from suppression of plant defense reactions, an increase in the number of nodules and a dramatic improvement in nodule development and infection), one (Stylosanthes hamata) responded negatively (fewer nodules and less nitrogen fixation) and four species (Aeschynomene americana, Aeschynomene afraspera, Indigofera tinctoria, and Desmodium tortuosum) displayed no phenotype. We also tested the role of the T3SS in the ability of the DOA9 strain to endophytically colonize rice roots, but detected no effect of the T3SS mutation, in contrast to what was previously reported in the Bradyrhizobium SUTN9-2 strain. Taken together, these data indicate that DOA9 contains a functional T3SS that interferes with the ability of the strain to interact symbiotically with legumes but not with rice