Active root distribution pattern of <Emphasis Type="Italic">Hevea brasiliensis</Emphasis> determined by radioassay of latex serum

The active root distribution pattern of mature rubber (Hevea brasiliensis Muell. Arg.) up to a lateral distance of 250 cm from the tree and to a soil depth of 90 cm was studied in an oxisol by employing ³²P soil injection technique in Kerala, the state which accounts for 83% of rubber cultivation in India. The trees were aged 18 years and grown at a spacing of 4.9 × 4.9 m. The extent of absorption of applied ³²P by the tree from various placements was assessed by radio assay of leaf and latex serum. Latex serum registered higher counts and variability was less compared to leaf indicating the suitability of latex serum as a potential source for radio assay for ³²P studies in rubber. The results revealed that rubber is a surface feeder with 55% of the root activity confining to the top 10 cm of soil layer. Root activity declined with increasing depths and the concentration of physiologically active roots at 90 cm depth was only 6%. A more or less uniform distribution of root activity was noticed with respect to lateral distance indicating more extensive spread of lateral roots. Concentration of physiologically active roots in the surface layer suggests the possibility for competition under intercropped situation in mature plantations.     

Possibilities of diverse rubber based agroforestry systems for smallholdings in India

Rubber growers in South East Asian countries are facing acute crisis due to the price volatility, sharp increase in cost of cultivation, increasing drought and declining soil fertility. With an objective to generate additional income and improve small-holder welfare by integrating diverse crops in rubber ecosystem, three experiments were conducted in Rubber Research Institute of India during 2001–2014 period. In one experiment, coffee, vanilla on Glyricidia standards, Garcinia and nutmeg were cultivated along with rubber without altering the planting design and density of rubber trees. Growth of rubber was significantly higher under mixed planting and yield was not influenced. Soil moisture status during summer and microbial population were higher in mixed planting system and soil nutrient status was maintained. Yield of all the intercrops was good during initial years. As the shade from rubber canopy intensified, Garcinia perished but vanilla and coffee continued to yield reasonably well. In another experiment, nine shade tolerant medicinal plants were evaluated in mature rubber plantation. All the medicinal plants established well and produced reasonable biomass, but the performance of Strobilanthes cuspida and Alpinia calcarata were comparatively better. In another study, it was observed that short duration vegetables like amaranthus and salad cucumber can be cultivated during the annual leaf shedding period in mature rubber plantations to meet part of the household requirement. The results showed that diverse crops can be integrated with rubber without any adverse effect on growth and yield of rubber. Crop diversification generated additional income, mitigated drought and sustained soil fertility.     

Effect of dietary supplemental ascorbic acid and folic acid on the growth performance,redox status,and immune status of broiler chickens under heat stress

This experiment was conducted to investigate the effects of dietary supplemental L-ascorbic acid (AA) and folic acid (FA) on broiler chickens under heat stress (HS) conditions when supplemented either alone or in combination. For this aim, the effect of these supplements on the broilers’ growth performance, some blood parameters, antioxidant, and immune status were evaluated. Hatchling Cobb-500 broilers (total = 240) were fed either corn and soybean meal-based diet (control group) or basal diet supplemented with 200 mg AA/kg diet, 1.5 mg FA/kg diet, or 200 mg AA plus 1.5 mg FA/kg diet, for 35 days during the summer months (n = 6 replicates/group, 10 birds/replicate). The minimum and maximum average temperatures ranged from 84.5 to 96.2 °F, and the relative humidity ranged from 68.5 to 76.5%. Supplemented vitamins either alone and (or) in combination increased (P < 0.01) broilers’ growth performance, thyroid hormones levels, insulin growth factor1, blood hemoglobin, total protein, albumin, globulin, heat shock protein70, total antioxidant capacity, catalase enzyme activity, superoxide dismutase enzyme activity, antibody titer against Newcastle disease virus, and decreased (P < 0.01) heterophil/lymphocytes. The effects (P < 0.01) of the supplemented vitamins on the analyzed parameters were better when they were added in combination. In conclusion, the combination of AA and FA at 200 and 1.5 mg/kg, respectively, increased the broilers’ antioxidant status with coordinated improvement in the growth performance and health status under HS.

     

Marker‐trait association analysis for postharvest needle retention/abscission in balsam fir (Abies balsamea)

Balsam fir the principal tree species of the Christmas tree industry, is a major export commodity of Atlantic Canada region. However, postharvest needle abscission poses a main concern leading to low consumer satisfaction and a shift in preference towards artificial trees. The search for diverse balsam fir lines with high needle retention is very crucial for quality improvement programmes. In this regard, a panel of 75 balsam fir genotypes exhibiting diversity for needle retention traits were randomly selected from a set of 220 genotypes evaluated for needle retention characteristics for two consecutive years (2012 and 2013) and genotyped with 41 bi‐allelic single nucleotide polymorphism (SNP)/insertion/deletion markers. The cluster analysis and population structure identified four and seven subpopulations. We observed an SNP marker with significant association (p < 0.05) with the needle retention/abscission trait by using general linear model and mixed linear model approaches. The present study lays the foundation for analysing the genetic mechanisms underlying needle retention/abscission, as well as the use of molecular markers to target specific traits in balsam fir.     

Curcumin analogue inhibits lipid peroxidation in a freshwater teleost, <Emphasis Type="Italic">Anabas testudineus</Emphasis> (Bloch)—an in vitro and in vivo study

The effect of a synthetic curcumin analogue (salicylcurcumin) on fish lipid peroxidation was investigated in both in vitro and in vivo conditions using a teleost model Anabas testudineus (Bloch). Curcumin analogue inhibited the formation of lipid peroxidation products and thiobarbituric acid reactive substances (TBARS) content at the three concentrations (10⁻² M, 10⁻³ M and 10⁻⁴ M) in vitro. TBARS content was reduced by 80% in the liver and 68% in brain by the higher concentration of salicylcurcumin. For in vivo study, salicylcurcumin (0.5%) was supplemented along with the basal feed for a period of 60 days. It produced a 60% reduction in liver TBARS content. The antioxidant enzyme superoxide dismutase (SOD) was stimulated, whereas catalase (CAT) and glutathione peroxidase (GPx) were inhibited. Glutathione (GSH) was reduced and glutathione reductase (GR) unchanged. Even though there was an increase in SOD activity, the CAT and GPx did not increase accordingly, maybe due to the direct scavenging of H₂O₂ by salicylcurcumin. The protein content also increased in the curcumin-fed animals, indicating a positive growth-promoting effect. Therefore, it would be beneficial to supplement salicylcurcumin along with the aquaculture feed in order to help the fish to cope with adverse conditions in the environment. This would increase the survival rate, disease resistance and ultimately the growth rate.