Co-inoculation of indigenous Pseudomonas oryzihabitans and Bradyrhizobium sp. modulates the growth, symbiotic efficacy, nutrient acquisition, and grain yield of soybean

Soil microbes play a vital role in improving plant growth, crop productivity, and soil health through solubilization of essential nutrients. Present investigation was conducted to access the efficacy of Bradyrhizobium sp. LSBR-3 and the indigenous phosphate-solubilizing Pseudomonas oryzihabitans LSE-3 in improving the symbiosis, nutrient accumulation, and yield of soybean. The isolate LSE-3, selected on the basis of phosphate solubilization, was screened for beneficial traits, antagonistic activities, and pathogenicity. The levels of indole acetic acid production (50.34 ±2.35 μg mL^-1), phosphate solubilization (184.4 ±7.4 mg L^-1), biofilm formation (optical density at 560 mm, 1.389 6 ±0.04), siderophore production (121.46 ±1.61 μg mL^-1), and 1-aminocyclopropane-1-carboxylate deaminase activity (0.51 ±0.07 mmol α-ketobutyrate μg^-1 protein h^-1) were significantly higher with the dual inoculants (LSBR-3 and LSE-3) than with the single inoculant LSBR-3. The plant growth-promoting traits of single and dual inoculants were evaluated for the synergistic effects on soybean under field conditions. Soybean plots treated with LSBR-3 + LSE-3 exhibited improvement in seed germination, plant height, plant biomass, and chlorophyll content compared with the uninoculated control. Dual inoculant treatments resulted in significantly higher symbiotic efficacy evidenced by increased nodulation (40.0 ±0.75 plant^-1), nodule biomass (188.52 ±6.29 mg plant^-1), and leghemoglobin content (11.02 ±0.83 mg g^-1 fresh nodule), and significantly increased activities of phosphatase (75.16 ±3.17 and 58.77 ±6.08 μg p-nitrophenol g^-1 h^-1 for alkaline and acid phosphatase, respectively) and dehydrogenase (32.66 ±1.92 μg triphenylformazan g^-1 h^-1) compared with the control. Dual inoculation with LSBR-3 and LSE-3 enhanced the uptake of macro- and micronutrients, reduced Na content in shoots, and resulted in 10.85% higher grain yield and ca. US$96.80 ha^-1 higher profit compared with the control. This is the first report on the effectiveness of combined inoculation of LSE-3 and LSBR-3 in promoting the growth, symbiotic efficacy, and yield of soybean for sustainable agriculture.     

Effects of various organic amendments on organic carbon pools and water stable aggregates under a scented rice–potato–onion cropping system

Pools of organic carbon are quantified from the soil samples under scented rice crop from different soil layers (0–10, 10–20, and 20–30 cm) under 9 years’ long-term trials with five treatments in scented rice–potato–onion cropping system. These treatments were 100 % NPK (NPK), 50 % recommended NPK through mineral fertilizers + 50 % N as FYM (NPK + FYM), FYM + vermicompost (VC) + neem cake (NC) each equivalent to one-third of recommended N (FYM + VC + NC), 50 % N as FYM + biofertilizer for N + bone meal to substitute phosphorus requirement of crops + phosphate solubilizing bacteria (FYM + BFN + BM + PSB), FYM + vermicompost + neem cake each equivalent to 1/3rd of recommended N + PSB (FYM + VC + NC + PSB). SMBC (479 mg kg^?1), HWEOC (373 mg kg^?1), CWSCHO (235 mg kg^?1), HWSCHO (839 mg kg^?1), and ASCHO (180 mg kg^?1) were found to be the highest in the soil treated with FYM + VC + NC + PSB and the lowest with NPK. The quantity of hot water-extractable carbohydrate content is highest amongst cold water, dilute acid and hot water extractable carbohydrate that decreases with the soil depth irrespective of treatments, except CWEOC. Soil microbial biomass carbon (SMBC) shows significant correlation with CWEOC (r = 0.60**), HWEOC (r = 0.94**), CWSCHO (r = 0.75**), HWSCHO (r = 0.83**), and ASCHO (r = 0.83**) that primed for better aggregate stability irrespective of soil layers up to 30 cm depth. This indicates that labile carbon pools, most specifically water-soluble carbon, carbohydrate, microbial biomass, could be a suitable indicator for evaluation of soil quality, particularly in relation to soil aggregation.     

From scientific obscurity to conservation priority: Research on angler catch rates is the catalyst for saving the hump‐backed mahseer Tor remadevii from extinction

1. The mahseer (Tor spp.) fishes of South and Southeast Asia are iconic megafaunal species that are highly valued by recreational anglers. Knowledge on their populations is limited owing to the challenges associated with sampling these large‐bodied fishes (>50 kg) in remote monsoonal rivers.
2. Despite its global iconic status among recreational anglers, the hump‐backed mahseer of the Cauvery River (South India) lacked a valid scientific name and was on a trajectory towards extinction until its rapidly declining population status was established by analyses of angler catch records.
3. Angling records from 1998 to 2012 showed that mahseer catch rates had increased in this period. The resulting publication in Aquatic Conservation (AQC) highlighted the positive role of catch‐and‐release angling in providing information on data‐poor species. However, further analyses showed that these catches comprised not one but two distinct phenotypes.
4. Before 1993, all mahseer captured were hump‐backed; since then, a blue‐fin phenotype appeared in catches and subsequently dominated them. These results triggered further studies indicating that the hump‐backed mahseer was the endemic Tor remadevii and that the blue‐fin was the invasive Tor khudree, introduced in 1976 and then stocked periodically from hatcheries.
5. The initial AQC publication successfully demonstrated the high value of organized angling as a monitoring tool for data‐poor fishes and its application to assessing the temporal population patterns of large‐bodied fishes in monsoonal rivers. It was also the catalyst for initiating subsequent studies on T. remadevii that, together, enabled its recent assessment as ‘Critically Endangered’ on the International Union for Conservation of Nature (IUCN) Red List. In the absence of the AQC paper, and the subsequent studies that it triggered, it is highly probable that the species would have remained on a trajectory towards rapid extinction. Instead, the first major steps to safeguarding its future have been taken.

     

Effects of Nandrolone and TGF-β1 in growing rabbits with osteopenia induced by over-supplementation of calcium and vitamin D3

The study was undertaken to find out the effects of over supplementation of dietary calcium and vitamin D3 on the mineralization of growing skeleton, taking rabbit as an animal model; further to study the effects of Nandrolone deconoate and TGF-β1 on the mineralization of osteopenic bones. Twenty four New Zealand White rabbits of either sex, 60 day old, were randomly divided in 4 equal groups, A, B, C and D. The animals of groups B, C and D were administered with oral supplementation of calcium (2000 mg/kg of standard rabbit feed) and vit-D3 (1000 IU/kg of standard feed) for 60 days. The animals of group A were given standard ration without any supplementation. After 60 days, the Ca-vit.D3 supplementation was discontinued; and the animals of group C were administered with TGF-β1 (10 ng, i.m.) once in every three days and animals of group D were given Nandrolone deconoate (10 mg, i.m.) once every week for 30 days, whereas in animals of group B, no treatment was given. All the animals were evaluated based on different observations like body weight, radiographic observations, circulating biochemical and hormone profile (plasma Ca, IP, AP, OC and iPTH) every 15 days up to 60 days after initiation of treatment. The results indicated that the body weight of rabbits in different groups increased gradually and steadily at different intervals till the end of observation period, however, the increase was non-significantly more in group D. The CI in group A increased gradually at different intervals; whereas in groups B, C and D, there was no appreciable increase in the CI during the period of Ca-vit.D3 supplementation, suggesting development of osteopenia. Treatment with TGF-β1 did not increase the CI significantly, whereas Nandrolone treatment resulted in significant increase in the CI on days 45 and 60. The plasma Ca levels showed slight but gradual increase from day 0 to 60 in almost all groups. Subsequently also, there was no marked change at different intervals in groups A and B; however, significant reduction in plasma Ca was noticed in group C on 15^th day and in group D on 60^th day after initiation of treatment. Plasma IP levels in groups B and C showed a decreasing trend up to day 60. After discontinuation of Ca-vit.D3 supplementation, in group B, it further decreased to remain significantly lower on 15^th day, and in groups C and D, it increased significantly on 60^th post-treatment day. There was no significant change in the AP activity during the entire period of study in group A; whereas significant reduction in AP activity was measured on 30^th and 60^th days of treatment in groups B and C, and on 15^th day of treatment in group D. Plasma iPTH values did not show any significant change at any interval during the first 60 days in all groups. On 30^th and 60^th days of treatment, the mean iPTH level remained significantly lesser in group B. In all groups treated with over supplementation of Ca and vit.D3, there was a non-significant increase in the plasma OC levels up to day 60; however, there was no significant difference between the groups. It can be concluded that additional supplementation of Ca and vit.D3 results in osteopenia in growing rabbits. Administration of Nandrolone helps to increase the mineral density in osteopenic bones, whereas TGF-β1 does not seem to have positive effect on the skeletal mineralization.