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The performance of rhizobia in soybean nodules under drought stress conditions was analyzed using five Bradyrhizobium strains selected according to the osmotic stress tolerance in liquid medium. The effect of selected rhizobial strains on root and nodule antioxidant response and symbiotic performance was evaluated in a soil pot experiment under different levels of drought stress (0, 3, 5, 7 days withholding water). Drought stress increased the guaiacol peroxidase (POX) and ionically cell wall-bound peroxidase (POD) activity, antioxidant capacity, soluble protein content in roots and nodules, reduced the shoot dry weight (SDW), and increased the nitrogen content in the roots. Under water deficit conditions the highest increase of antioxidative parameters was recorded in the nodules of strain 216, and the lowest in roots and nodules of the plants inoculated with strain 511. Inoculation with strain 511 resulted in significantly lower SDW, root dry weight (RDW) and plant nitrogen content, while application of strain 216 resulted in the highest shoot attributes. Rep-PCR characterization and 16S-23S rDNA intergenic region sequencing emphasized the differences in strains genomic organization, especially for the 216 strain showing the higher tolerance to osmotic stress. The results implicate similarity between strain performance under osmotic stress in liquid medium and in symbiotic association under drought stress. The results also suggested important contribution of rhizobial strains in enhancing antioxidative response under drought stress and in symbiotic effectiveness, indicating more sensitive and tolerant symbioses.

Solanum lycopersicum L. là một loại cây trồng phổ biến trên toàn thế giới với giá trị kinh tế nổi bật cho ngành công nghiệp thực phẩm. Một thí nghiệm trong chậu đã được thực hiện để nghiên cứu độc tính cadmium ở Solanum lycopersicum L. cv Pusa Ruby và khả năng cải thiện độc tính này bằng cách bổ sung α-lipoic acid (ALA) qua lá. Cây được trồng dưới các nồng độ CdCl2 khác nhau (10, 25, 50, 100 mg kg−1 đất) và được phun hai lần với dung dịch ALA 0.1 mM vào ngày 30 và 45 của quá trình sinh trưởng. Sự tích lũy Cd, tăng trưởng cây, chỉ số độc tính, sắc tố quang hợp, chuyển hóa nitơ và các enzyme chống oxy hóa đã được xác định ở những cây 60 ngày tuổi. Kết quả cho thấy sự tích lũy Cd cao hơn đáng kể ở rễ so với thân. Độc tính cadmium đã làm giảm tăng trưởng cây, sắc tố quang hợp và hoạt động của các enzyme đồng hóa nitơ, trong khi nâng cao có ý nghĩa (P ≤ 0.05) sự peroxy hóa lipid và sự tích lũy H2O2 theo hàm lượng. Bổ sung ALA qua lá đã giảm độc tính Cd lên sắc tố quang hợp và chuyển hóa nitơ bằng cách giảm sự tích lũy Cd, các chỉ số độc tính và cải thiện hoạt động của các enzyme chống oxy hóa ở mỗi điều trị Cd tương ứng. Hàm lượng H2O2 và MDA đã giảm lần lượt là 23% và 55% ở nồng độ 10 mg Cd. Trong các điều kiện tương tự, hoạt động của NR, GOGAT, SOD, và APX đã được tăng cường lần lượt là 10%, 21%, 26% và 10% so với nhóm đối chứng. Nghiên cứu kết luận rằng ALA có thể được sử dụng hiệu quả trong việc cải thiện độc tính cadmium ở cây cà chua.

Amaranthus retroflexus seeds were dormant at 25 °C in the darkness and in the light, and also at 35 °C in the darkness. GA3 and ethylene partially removed dormancy at 35 °C in the darkness and at 25 °C in the light. Dormancy was removed by 1–5 days of treatment with nitric oxide or cyanide. The effect of NO and HCN was inhibited by cPTIO, thus the effect of HCN was NO dependent. Dry storage for 16 weeks could partially release dormancy only at 35 °C, but not at 25 °C. Dry storage increased the response to light, GA3 and ethylene. The response to GA3 and ethylene at 25 °C was enhanced with increasing storage temperature. GA3, ethylene and nitric oxide could substitute dry storage and stratification in partially dormant seeds.

Legumes as an important functional group of land plants are recognized to grow in water-deficient and low-nutrient environment because of their ability to form symbiosis with nitrogen fixing rhizobia and arbuscular mycorrhizal (AM) fungi, which improve nutrient acquisition from the soil and help plants to be well established. Aim of the present study was to evaluate the symbiotic potential of AM fungi, Glomus intraradices alone and/or in combination with two Bradyrhizobium japonicum strains MN-S and TAL-102 in Vigna radiata. Field experiment was conducted to investigate the influence of different microbial symbiotic associations on growth and yield of V. radiata. Dual inoculation of G. intraradices and both bacterial inoculants showed better potential of plant growth promotion over single inoculation of G. intraradices or bacterial inoculants. Both bacterial inoculants in combination with AM proved best with 3.78, 30.17 and 46.80 g plant−1 dry weight at 25, 45 and 90 days after sowing (DAS), respectively. Maximum grain yield of 1,506.87 kg ha−1 as well as phosphorus contents of 1.981 mg g−1 root, 3.830 mg g−1 shoot and 4.935 mg g−1 grain were observed with mix bacterial inoculants and AM at 90 DAS. The interactive effect of bacterial inoculants and AM was synergistically significant which improved the nitrogen contents by 68, 20 and 17% in root, shoot and grain, respectively, compared to uninoculated control at 90 DAS. The present study suggests the suitability of G. intraradices and B. japonicum having synergistic or additive interaction to be used as composite inoculum for enhancing crop production of V. radiata.

Triterpenic saponins represented in Calendula officinalis L. by oleanolic acid (OA) glycosides are pentacyclic triterpene compounds with a wide range of biological and medicinal properties. This report demonstrates nitrogen source impact on growth, saponin accumulation, and secretion in hairy root and suspension cultures of marigold. Hairy roots preferred nitrate as a mineral source of nitrogen, but its impact on growth, OA glycosides accumulation, and secretion were line-dependent. The best productivity of OA glycosides was found in CC16 line (74.86 mg flask−1) in ½ MS medium modified by 2.5× KNO3 and ammonium elimination with 2.5 g l−1 peptone. Organic nitrogen source at 27.5-g l−1 impairs the growth rate of hairy roots. Its effect on saponin accumulation and secretion to the surrounding medium depended on line and media composition. Nitrate:ammonium ratio of 4:2 for CC16 resulted in 5.7-fold increment of saponin secretion comparing to the standard medium. Embryo roots, apical bud, and hypocotyls explants were crucial for induction of suspension culture synthesizing saponins; however, effect of mineral form of nitrogen in cultivating medium had to be considered. The highest OA glycosides level (171.97 μg g−1 of dry weight) was recorded in the root derived culture with nitrate as a sole mineral form of nitrogen. Peptone from lactalbumin decidedly inhibited the saponin formation; however, it was essential for culture initiation, proliferation, and organ differentiation.

Columnar apples are a labor saving and productive tree form that has long been of interest to apple breeders and producers. MdCo31, which encodes a putative 2OG-Fe(II) oxygenase, is a potential candidate gene involved in controlling the internode length of columnar growth of apple. In this study, a putative regulation in internode length was conducted by exogenous application of GA3 and paclobutrazol. The results showed that the MdCo31-GFP fusion protein was specifically localized in the cytoplasm. Heterologous over-expression of MdCo31 in tobacco produced stunted phenotypes with high chlorophyll content in leaves, and delayed the timing of seed germination and flowering. The over-expression tobacco plants were more sensitive to exogenous application of GA3 but insensitive to paclobutrazol, and their growth correlated to lower concentrations of endogenous GA1 and lower expression levels of the gibberellin-regulated family gene NtGASA6. The higher the MdCo31 expression levels were identified in more dwarf transformants with the shorter internodes. This research proposed that the decrease in endogenous GA1, resulting from high MdCo31 expression, induced dwarf phenotypes and shorted internodes, which indicated that MdCo31 is responded to gibberellins’ deficiency conferring the internodal growth of columnar apples.

In this study, aqueous extracts of Calliandra haematocephala Hassk. leaves and inflorescences were tested on seeds of quinoa (Chenopodium album L.) and rice (Oryza sativa L.), and on some of the most noxious-associated weeds, Chenopodium album L. and Holcus lanatus L. in quinoa, and Echinochloa crus-galli (L.) P. Beauv., Echinochloa colona L., Eclipta prostrata L. and Rottboellia cochinchinensis (Lou.) W.D. Clayton in rice. The objectives were to identify extract concentrations at which 50 and 90% of germination (GR$$_{[50,90]}$$) and radicle elongation (RR$$_{[50,90]}$$) were inhibited, to fractionate inflorescence extracts for facilitating identifying the chemical group causing allelopathic effects, and to evaluate the fraction showing the stronger weed suppression effects and the least crop damage. Increasing extract concentration rates (0, 6.25, 12.5, 25, 50 and 100% crude extract) were applied to seeds of target crops and weeds. Flower extracts at rates $$< 0.30$$ produced GR$$_{[50]}$$ and RR$$_{[50]}$$ on H. lanatus, and GR$$_{[90]}$$ and RR$$_{[90]}$$ in C. album, while quinoa seeds were not affected. Rice and its target weeds were minimally affected by flower extracts, whereas radicle elongation of all species was significantly reduced. A concentration rate $$> 0.52$$ caused the RR$$_{[50]}$$ on rice and all its target weeds. Fractions were quantitatively and qualitatively analysed to detect phytochemical groups, using specific chemical reagents and thin-layer chromatography (TLC). The fraction F3 from aqueous flower extract showed a high content of flavonoids, assumed as the potential allelochemical substance. Total flavonoid content in F3 was quantified as 2.7 mg of quercetin per g F3, i.e., 12.8 mg of quercetin per g of inflorescence material. Additionally, field equivalent extract rates obtained from the harvested fresh inflorescence biomass could be determined. These rates ranged between 90 and 143 mL l−1 of F3 aqueous fraction, while for ethanol F3 were 131 mL l−1. Our results are encouraging for finding sustainable and ecologically friendly alternatives for weed management in crops of high nutritional value, contributing also to counteract the growing problem of herbicide resistance.

An efficient and improved in vitro propagation method has been developed for Terminalia bellirica, a medicinally important tree from nodal explants of 10-year-old mature tree. Shoot multiplication was influenced not only by cytokinin types, their concentrations and their interaction with auxin but also by successive transfer of mother explants for different passages, subculture of excised shoots on fresh medium and different medium composition. MS medium containing 2.22 μM BAP was found to be the best for shoot multiplication in a single step. After excision of newly formed shoots, mother explants successively transferred to the same medium produced maximum shoots per explant after IV passage. Further enhancement in morphogenetic response occurred when excised shoot clumps (2–3 shoots) were subcultured on MS medium supplemented with 2.22 μM BAP, 1.16 μM Kn and 0.57 μM IAA. Half-strength MS medium supplemented with 24.60 μM IBA and 100 mg l−1 AC was most effective for rooting of the shoots. To reduce labor, cost and time, an experiment on ex vitro rooting was also carried out and it was observed that highest percent shoots rooted ex vitro when treated with 2,460 μM IBA for 5 min. Plantlets rooted in vitro as well as ex vitro were acclimatized successfully under the green house conditions. In comparison to plantlets developed from in vitro rooted, percent survival of plants those rooted ex vitro was significantly higher. Use of ex vitro rooting technique for plant production serves as a more economical option; therefore, present method can be used for large-scale commercial production of this medicinally important tree.

Các kinase phụ thuộc vào canxi (CDPKs hoặc CPKs) là những cảm biến Ca2+ quan trọng trong thực vật, liên quan đến phản ứng của thực vật đối với các yếu tố stress vô sinh và hữu sinh, chẳng hạn như sự đóng khí khổng do hạn hán hoặc sản xuất stilbene do tác nhân gây bệnh. Chúng tôi đã phát hiện ra rằng gen VaCPK9 của Vitis amurensis bị xử lý sau phiên mã bất thường thông qua các vị trí cắt ghép điển hình dẫn đến việc sản xuất ba isoform mRNA mà thiếu các miền kinase xúc tác quan trọng. Chúng tôi cũng phát hiện nhiều cDNA VaCPK9 và VaCPK3a không điển hình mang các chuỗi lặp ngắn trực tiếp thay vì các vị trí cắt ghép điển hình và gợi ý rằng các cDNA này là các bản sao thay thế giả được tạo ra bởi sự chuyển đổi mẫu của lặp lại phiên mã ngược in vitro. Nghiên cứu hiện tại đã được tiến hành để xác định liệu các CDPKs dài đầy đủ và được cắt ghép có vai trò trong việc điều chỉnh sự phát triển của cây nho, tổng hợp stilbene và thích nghi với stress vô sinh hay không. Chúng tôi đã tạo ra các văn hóa callus V. amurensis chuyển gen biểu hiện quá mức các bản sao VaCPK9 và VaCPK3a thật và giả khác nhau dưới sự kiểm soát của promoter CaMV 35S. Việc biểu hiện quá mức các bản sao dài đầy đủ VaCPK9 và VaCPK3a chỉ làm tăng nhẹ sự tích lũy sinh khối nhưng không ảnh hưởng đến khả năng chống chọi với stress vô sinh cũng như tổng hợp resveratrol (3,5,4'-trihydroxy-trans-stilbene) trong các callus. Việc biểu hiện quá mức các bản sao thay thế thật VaCPK9SF1, VaCPK9SF2, và VaCPK9SF3 đã cải thiện đáng kể sự phát triển của các callus chuyển gen, trong khi việc biểu hiện quá mức các bản sao thay thế giả VaCPK3aSF1, VaCPK3aSF2, và VaCPK3aSF3 không ảnh hưởng đáng kể đến điều này. Kết quả cho thấy rằng các gen VaCPK9 và VaCPK3a thực hiện chức năng trong việc điều chỉnh sự phát triển của V. amurensis nhưng không tham gia vào quá trình tổng hợp stilbene và khả năng chịu stress vô sinh. Việc cắt ghép thay thế của VaCPK9 có thể đóng vai trò củng cố tác động tích cực của sự biểu hiện VaCPK9 lên sự tích lũy sinh khối.