Identifying other suitable and potential indigenous carrageenophytes for commercial cultivation in India

In India, Kappaphycus alvarezii is the only alga being cultivated commercially for kappa carrageenan production and also being utilized for the socioeconomic upliftment of coastal rural population in India in the form of their cultivation and marketing. The production has been substantially increased from 21 dry tonnes to 1490 dry tonnes with increasing market purchase value from US$ 0.061 to 0.469 kg dry wt^?1 during 2001–2013. In India, annual import for carrageenan is 1800–2000 M tons year^?1 and its demand is reported to be increased by 5–6% every year (Mantri et al. 2017). To date, Aquagri Pvt Ltd is the only company in India producing kappa carrageenan from cultivated Kappaphycus alvarezii (Mantri et al. 2017). However, few other marine phycocolloid processing factories are producing kappa carrageenan from Hypnea musciformis and Hypnea valentiae at cottage level. The total annual production of carrageenan in India ranges between 100 and 132 tons. There is tremendous demand for other carrageenan such as iota and lambda carrageenan in food, beverage, and consumer product manufacturing industries. In order to ascertain suitability of unexplored other indigenous carrageenophytes for commercial cultivation in India, several red algal species such as Agardhiella subulata, Ahnfeltiopsis pygmaea, Laurencia caraibica, and Solieria robusta were collected from wild habitats in Kanyakumari (N 08°08′10.36″; E 077°34′28.06″) Tamil Nadu, India, and were evaluated for their mariculture potential and the presence of carrageenan. Preliminary cultivation experiments were carried out by raft culture method (1?×?1 m) for 45 days at two harvest cycles at Thonithurai (N 09°16′53.45″; E 079°11′19.22″), Tamil Nadu, South eastern coast of India. Except Ahnfeltiopsis pygmaea, all other seaweeds investigated showed daily growth rate (DGR) in the range of 1.59 to 3.822% and confirmed its mariculture potential. Phycocolloid was extracted with yield 4.5 to 29.37% from dry seaweed residues obtained after extraction of lipids using both water and aqueous alkali [5% Ca (OH)₂ solution]. Water was found the better solvent in terms of higher yield of the Phycocolloid (29.37%) from Solieria robusta. FT-IR of the extracted phycocolloid indicated presence of characteristic bands for carrageenan in all the samples. However, from the band positions, the presence of iota carrageenan was ascertained in the Agardhiella subulata and Solieria robusta and hybrid iota/kappa carrageenan is expected to be present in Laurencia caraibica and Ahnfeltiopsis pygmaea.

     

Performance of growing rabbits fed concentrate and Stylosanthes (Verano) combinations under tropical conditions

The performance of growing crossbred rabbits fed concentrate and Stylosanthes hamata (stylo) at different ratios was evaluated. The following ratios were used: 25:100, 50:75, 75:50, 100:25 and 125:10 (g : g; weight supplied per day). Total weight gain was lower and the feed : gain ratio (FGR) was higher with the 25:100 combination than with the other combinations. Daily feed intake significantly (P < 0.01) decreased, whereas feed cost and cost per kg intake increased as the concentrate level increased. Cost per kg gain increased with increases in concentrate levels up to 100 g before decreasing at 125 g. Weight gain, cost per kg intake and cost per kg gain had a quadratic relationship with concentrate level, whereas FGR and feed cost had a linear relationship. Time required to attain a market weight of 2.5 kg and total feed required to attain market weight decreased, whereas total cost of feeding increased with increases in concentrate level. Dry matter and ash digestibility were similar for all the treatments. Ether extract digestibility was lower for the 25:100 combination compared with the other treatments. Crude protein, nitrogen‐free extract digestibility and nitrogen retention were significantly lower for the 25:100 combination (0.74, 0.66 and 0.64) compared with the 100:25 combination (0.83, 0.75 and 0.79). The dressing percentage was similar for all treatments, whereas the proportion of live weight represented by the head increased with an increase in concentrate level. This study shows that rabbits are able to utilize leaf protein in stylo for growth even at the lowest level of concentrate.     

Influence of irradiance on water relations and carbon flux during rooting of Shorea leprosula leafy stem cuttings

Single-node leafy stem cuttings of Shorea leprosula Miq. were subjected to a high, intermediate or low irradiance treatment for 16 weeks in an enclosed mist propagation system. Before rooting, maximum photosynthesis of the cuttings occurred at an irradiance of 400 micro mol m(-2) s(-1). Although none of the irradiance treatments affected the number of roots produced per cutting, the numbers of cuttings that formed roots were 50 and 30% in the high irradiance (diurnal range of 0-658 micro mol m(-2) s(-1)) and low irradiance (diurnal range of 0-98 micro mol m(-2) s(-1)) treatments, respectively, compared with 62% in the intermediate irradiance treatment (diurnal range of 0-360 micro mol m(-2) s(-1)). Low rooting frequency of cuttings in the high irradiance treatment was associated with water deficits (maximum leaf-to-air vapor pressure deficit (VPD) = 3.6 kPa), whereas cuttings in the low irradiance treatment had a low rooting frequency because they were below the light compensation point most of the time. In the intermediate irradiance treatment, cuttings withstood a daily maximum VPD of 1-2 kPa and recovered overnight from the previous day's deficit, as indicated by higher relative water content (RWC) and stomatal conductance (g(s)) in the morning than in the previous afternoon and evening. Higher RWC and g(s) of cuttings in all treatments on Days 14 and 21 compared with Day 8 probably indicated recovery from water deficit following severance and insertion of the cuttings in rooting medium. There were negative relationships between stem volume of cuttings and both number of cuttings that rooted and number of roots per cutting.     

Antimicrobial activity of Leucas aspera flowers

The methanol extract of Leucas aspera flowers, its fractions, the alkaloidal residue and the expressed flower juice, tested for antimicrobial activity, showed good antibacterial activity for methanol extract and methanol fraction with maximum activity for the alkaloidal residue.     

Interspecific hybridisation of soybeans and perennial Glycine species indigenous to Australia via embryo culture

Summary Five sterile hybrids (2n=59) between a synthetic amphiploid of Glycine tomentella (2n=38) and G. caneseens (2n=40) as female and soybean cultivars Lincoln and Hark as males have been produced by embryo or ovule culture using transplanted endosperm. The hybrid plants are twining perennials like the female parent but possess a number of morphological characters which reflect the presence of the soybean genome. Indophenol oxidase isozymes from leaf extracts also provide good evidence of the hybrid nature of the cultured plants. These hybrids open the way for the exploitation of the diverse germplasm resources of the perennial Glycine species in soybean breeding.     

Long-term soil management effects on crop yields and soil quality in a dryland Alfisol

A long-term experiment was conducted with the objective of selecting the appropriate land management treatments and to identify the key indicators of soil quality for dryland semi-arid tropical Alfisols. The experiment was conducted using a strip split–split plot design on an Alfisol (Typic Haplustalf) in southern India under sorghum (Sorghum vulgare (L))-castor (Ricinus communis (L)) bean rotation. The strip constituted two tillage treatments: conventional tillage (CT) and minimum tillage (MT); main plots were three residues treatments: sorghum stover (SS), gliricidia loppings (GL), ‘no’ residue (NR) and sub plots were four nitrogen levels: 0 (N₀), 30 (N₃₀), 60 (N₆₀), and 90 kg ha⁻¹ (N₉₀). Soil samples were collected after the sixth and seventh year of experimentation and were analyzed for physical, chemical and biological parameters. Sustainable yield index (SYI) based on long-term yield data and soil quality index (SQI) using principal component analysis (PCA) and linear scoring functions were calculated. Application of gliricidia loppings proved superior to sorghum stover and no residue treatments in maintaining higher SQI values. Further, increasing N levels also helped in maintaining higher SQI. Among the 24 treatments, the SQI ranged from 0.90 to 1.27. The highest SQI was obtained in CTGLN₉₀ (1.27) followed by CTGLN₆₀ (1.19) and MTSSN₉₀ (1.18), while the lowest was under MTNRN₃₀ (0.90) followed by MTNRN₀ (0.94), indicating relatively less aggradative effects. The application of 90 kg N ha⁻¹ under minimum tillage even without applying any residue (MTNRN₉₀) proved quite effective in maintaining soil quality index as high as 1.10. The key indicators, which contributed considerably towards SQI, were available N, K, S, microbial biomass carbon (MBC) and hydraulic conductivity (HC). On average, the order of relative contribution of these indicators towards SQI was: available N (32%), MBC (31%), available K (17%), HC (16%), and S (4%). Among the various treatments, CTGLN₉₀ not only had the highest SQI, but also the most promising from the viewpoint of sustainability, maintaining higher average yield levels under sorghum–castor rotation. From the view point of SYI, CT approach remained superior to MT. To maintain the yield as well as soil quality in Alfisols, primary tillage along with organic residue and nitrogen application are needed.     

Remediation of Acid Rock Drainage by Regenerable Natural Clinoptilolite

Clinoptilolite is investigated as a possible regenerable sorbent for acid rock drainage based on its adsorption capacity for Zn, adsorption kinetics, effect of pH, and regeneration performance. Adsorption of Zn ions depends on the initial concentration and pH. Adsorption/Desorption of Zn reached 75% of capacity after 1–2 h. Desorption depended on pH, with an optimum range of 2.5 to 4.0. The rank of desorption effectiveness was EDTA?>?NaCl?>?NaNO₃?>?NaOAc?>?NaHCO₃?>?Na₂CO₃?>?NaOH?>?Ca(OH)₂. For cyclic absorption/desorption, adsorption remained satisfactory for six to nine regenerations with EDTA and NaCl, respectively. The crystallinity and morphology of clinoptilolite remained intact following 10 regeneration cycles. Clinoptilolite appears to be promising for ARD leachate treatment, with significant potential advantages relative to current treatment systems.     

Mycorrhizal fungi of Pseudotsuga menziesii in the North Island of New Zealand

Attempts were made to isolate mycorrhizal fungi of a timber species, Pseudotsuga menziesii (Mirb.) Franco which is exotic to New ZeaLond. Over 2000 pieces of mycorrhizal roots were plated out on Hagem medium and modified Melin-Norkrans medium; 14% of these yielded Rhizopogon vinicolor A. H. Smith, 6% gave rise to Amanita muscaria (L. ex Fr.) S.F. Gray, and 7% to unidentified basidiomycetes, 21% yielded dark sterile mycelia, 13% were sporing Fungi Imperfecti presumed to be contaminants, and 39% remained free of fungal growth.Eleven basidomycetous fungi were tested for their mycorrhiza-forming ability on P. menziesii seedlings. Under the test conditions R. vinicolor, Hebeloma crustuliniforme (Bull, ex St. Am) Quel., A. muscaria, Scleroderma bovista Fr., Laccaria laccata (Scop, ex Fr.) Berk. & Br., Inocybe corydalina (?), I. jurana (?), and I. maculata (?) formed mycorrhizas.