Mitigation of Eutrophication in a Shallow Lake: The Influences of Submerged Macrophytes on Phosphorus and Bacterial Community Structure in Sediments

Remediating water eutrophication is critical for maintaining healthy and sustainable development of lakes. The aim of this study was to explore the seasonal variation in phosphorus (P) speciation and bacterial community structure in sediments of Qin Lake (Taizhou, Jiangsu Province, China) associated with the growth of submerged macrophyte Vallisneria natans. The differences in sediment bacterial diversity and community structure between V. natans growing and control areas were analyzed over a period of one year. The results showed that V. natans growth reduced the total P and organic matter contents of the sediments and increased the bioavailable iron (Fe) and Fe-bound P contents. The α-diversity of sediment bacteria was significantly higher in the presence of V. natans than in the controls during the vigorous plant growth stage. In the presence of V. natans, there was a higher relative abundance of Proteobacteria and lower relative abundances of Chloroflexi and Acidobacteria. The Fe(II) content in the sediment had a larger influence on the spatial distribution of bacterial communities than sediment Fe-bound P, organic matter, and Fe(II) contents. V. natans growth could reshape sediment bacterial community structure in the shallow lake, which, in turn, enhanced P immobilization in the sediments and thereby improved the water quality.

Sinorhizobium medicae WSM419 genes that improve symbiosis between Sinorhizobium meliloti Rm1021 and Medicago truncatula Jemalong A17 and in other symbiotic systems

Some soil bacteria called rhizobia can interact symbiotically with legumes in which they form nodules on the plant roots where they can reduce atmospheric dinitrogen to ammonia, a form of nitrogen that can be used by growing plants. Rhizobia/plant combinations can differ in how successful this symbiosis is—Sinorhizobium meliloti Rm1021 forms a relatively ineffective symbiosis with Medicago truncatula Jemalong A17 but Sinorhizobium medicae WSM419 is able to support more vigorous plant growth. Using proteomic data from free-living and symbiotic S. medicae WSM419, we previously identified a subset of proteins that were not closely related to any S. meliloti Rm1021 proteins and speculated that adding one or more of these proteins to S. meliloti Rm1021 would increase its effectiveness on M. truncatula A17. Three genes, Smed_3503, Smed_5985, and Smed_6456, were cloned into S. meliloti Rm1021 downstream of the E. coli lacZ promoter. Strains with these genes increased nodulation and improved plant growth, individually and in combination with one another. Smed_3503, renamed iseA (increased symbiotic effectiveness) had the largest impact, increasing M. truncatula biomass by 61%. iseA homologs were present in all currently sequenced S. medicae strains but were infrequent in other Sinorhizobium isolates. Rhizobium leguminosarum bv. viciae 3841 containing iseA led to more nodules on pea and lentil. Split root experiments with M. truncatula A17 indicated that S. meliloti Rm1021 carrying the S. medicae iseA is less sensitive to plant induced resistance to rhizobial infection, suggesting an interaction with the plant’s regulation of nodule formation. IMPORTANCE The legume symbiosis with rhizobia is highly specific. Rhizobia that can nodulate and fix nitrogen on one legume species are often unable to associate with a different species. The interaction can be more subtle—symbiotically enhanced growth of the host plant can differ substantially when nodules are formed by different rhizobial isolates of a species, much like disease severity can differ when conspecific isolates of pathogenic bacteria infect different cultivars. Much is known about bacterial genes essential for a productive symbiosis, but less is understood about genes that marginally improve performance. We used a proteomic strategy to identify Sinorhizobium genes that contribute to plant growth differences that are seen when two different strains nodulate M. truncatula A17. These genes could also alter the symbiosis between R. leguminosarum bv. viciae 3841 and pea or lentil, suggesting that this approach may identify new genes that may more generally contribute to symbiotic productivity.

Management of Wilt Complex of Chickpea with Seed Biopriming and Soil Application of Trichoderma spp.

Background: Chickpea wilt complex caused by several soil-borne pathogens is a serious biotic constraint for chickpea production.Methods: To find out the effective management of the disease through seed biopriming and soil application of biocontrol agents under in vivo and in vitro conditions experiments were carried out during rabi 2018-19 and 2019-20 at Anand Agricultural University, Anand, Gujarat.Result: Seed biopriming showed a positive impact producing vigorous plant shoot and root system, besides disease control during in vitro conditions. While under in vivo conditions, the pooled results of two years revealed that seed biopriming for 10 h with the suspension of talc-based formulation (2 x 108 CFU/g) of Trichoderma viride or T. asperellum @ 50 g in 250 ml of water/kg of seed followed by soil application of T. viride or T. asperellum enriched FYM (10g/kg FYM) @ 100 g/m2 of soil found significant for the disease management as well as higher yield. The seed biopriming alone control the disease in the range of 23-34% and increased the yield of chickpea by 23-29%. However, combined applications of seed biopriming as well as soil application significantly control the disease in the range of 51-70% and increased the grain yield by 41-51% over untreated control.

Mussaenda erythrophylla (red flag bush).

Mussaenda erythrophylla is a popular ornamental plant grown in parks and gardens across tropical and subtropical regions of the world. Their showy and colourful inflorescences (from bright crimson to deep red) make this plant attractive for horticulturalists. It has also escaped from cultivation and can be found naturalized in forest edges, secondary forests, riverbanks, shrubby savannahs, and in thickets along roadsides. Plants in cultivation usually do not produce fruits, but spread vegetatively by layering. M. erythrophylla is a species of environmental concern because it is a vigorous plant that can form dense thickets up to 10 m high that can easily outcompete and displace other vegetation including native plant species.

The bigger the better? Vigour of the exotic host plant Calotropis procera (Apocynaceae) affects herbivory

The Plant Vigour Hypothesis states that herbivores preferentially feed on the most vigorous plants within a plant population and/or the most vigorous modules within a plant. The goal of this study was to evaluate how shoot size (as an indication of module vigour) affects leaf herbivory in the host plant Calotropis procera, an exotic xerophyte perennial milkweed shrub. We predicted that the proportion of leaf area removed by insect herbivores would be positively related to shoot size. Eight patches were selected containing a varied number of C. procera individuals (5, 8, 29, 31, 55, 79, 116, and 172 individuals/patch) in the Brazilian seasonally dry vegetation (Caatinga), of which five individuals were randomly selected for further analysis. From each individual, three to six shoots were randomly selected, measured and had their leaves collected, for a total of approximately 200 leaves per patch. At the regional scale, the proportion of leaf area removed was positively affected by shoot size. In addition, this pattern was also found for the majority of the studied patches (29, 31, 55, 116, and 172 individuals/patch). Among the insect herbivores associated with C. procera, larvae of Danaus spp. (Lepidoptera: Nymphalidae) were commonly observed feeding on all patches. These herbivores present a specialized behaviour to circumvent the presence of latex in the host leaves. Although more vigorous plant modules should be better defended compared with the less vigorous modules, Danaus species were able to bypass host defences, and feed on healthy, rapidly growing and vigorous plant modules of C. procera, hence causing more damage to these modules.

Evaluating an Interspecific Helianthus annuus × Helianthus nuttallii Line for Use in Sunflower Breeding Program

Interspecific cross was made between the common sunflower inbred line HA89 and an accession of wild Helianthus nuttallii (2n=2x=34) resistant to the most harmful disease complex and tolerant to drought and high temperature. The recombinant inbred line was a BC1F15 progeny. The most remarkable feature observed was the vigorous plant habit that manifests itself in measurable morphological characters such as increment plant height, stem diameter and diameter of the head. The line was non-branched (monocephalic) without anthocyanin pigmentation and possessed good agronomic characteristics. Along with the morphological and reproductive traits, some biochemical characteristics related to antioxidant activity were associated to wide hybridization. The overall characteristics of HA-Hnutt line make it a useful plant material for research on interspecific hybridization in Helianthus genus.

Novo híbrido de orquídea Cattleya

The hybrid, obtained by back crossing between (Cattleya labiata x Cattleya forbesii) x Cattleya labiata is a vigorous plant, bi- or unifoliate, features slender and cylindrical pseudobulbs and leathery dark-greenish leaves, with oblanceolate shape format of blunt tips with the first flowering four years after sowing. In Londrina, flowering occurred twice a year, between the months of April and May and October and November with 2-4 flowers per pseudobulb and durability ranging from 15 to 20 days. The flowers of the new hybrid were purple with a labellum with a yellow center and purple stripes.

Effect of phosphate solubilizing bacteria and arbuscular mycorrhizal fungi with and without rock phosphate on four forest tree seedlings

The effect of phosphorus solubilizing bacteria Bacillus polymyxa and AM-mycorrhizal fungi Rhizophagus fasciculatus with and without rock phosphate treatments on growth of Terminalia paniculata and T. tomentosa were studied in nursery. The results showed that the combined inoculation of both PSB, AM fungi and rock phosphate produced vigorous plant growth of tree seedlings for quick planting. The experiments clearly demonstrated that the combined inoculation of PSB and AM fungi brought marked increase in plant growth, dry matter, and P uptake when, compared to individual inoculants or non-inoculated plants. The increase in growth was attributed to the increase in P uptake in shoots of the seedlings. The results indicated that both organisms have synergistic effect with additional 250 mg RP/kg rock phosphate treatment for T.paniculata Roth. and 150 mgRP/kg for T.tomentosa W.& A. in green house conditions.

Morphological studies and development of Ex-situ protocol for rehabilitation of threatened Rheum species under nursery conditions

<p><em>Rheum</em> is a strong vigorous plant and can live long even in tough conditions. The <em>Rheum</em> species have been domesticated as medicinal plants for human consumption. <em>Rheum</em> species are perennial stout herbs. Rhubarb is a common English name of the genus <em>Rheum</em>. Rhubarb is a plant name for the many different species of <em>Rheum</em>, distributed in the temperate and sub tropical regions of Himalaya from Kashmir to Sikkim and growing wild in the mountains of the Western and North-western provinces of China and adjoining Tibetan territory. It is cultivated much in Europe and the United States. In Kashmir Himalaya, it ranges from an altitude of 1700 - 5500m. It is famous for its medicinal uses. Roots are long and stout. Stem is erect, hollow, sulcate, glabrous or strigose. It is native to Asia-Temperate to Asia – Tropical, from China to India, Nepal and Pakistan. In India, its found in Himachal Pradesh Jammu &amp; Kashmir and Uttar Pradesh. In Jammu and Kashmir, it grows on open slopes and shrubberies in Kashmir, Leh and Zanaskar valley between 3000-5000 m, where <em>R.webbianum</em> is found. The <em>Rheum spiciforme</em> is also one of most known medicinal plant and is found on high altitudes of Gurez valley(3000m 5000m). <em>Rheum</em> also prefers a full sunny location and thrives in a moist, fertile soil. Most <em>Rheum</em> species can handle heavier clay soils better than many other herbs and makes a striking addition to the spring landscape. Rhubarb is propagated from seeds, seedlings, or pieces of rhizome. </p>