High night-time temperature during flowering and pod filling affects flower opening,yield and seed fatty acid composition in canola

Winter canola (Brassica napus L.) is highly sensitive to increasing temperatures during the reproductive and pod-filling stages. Although the impact of high day-time temperature stress on yield and quality has been documented in canola, similar information under high night-time temperature (HNT) stress is not available. Using six hybrids and four open-pollinated cultivars, we observed a marked shift in peak flowering towards earlier, cooler hours of the morning under HNT. Averaged across two independent experiments, the photochemical efficiency of photosystem II was significantly decreased (3%), with a significant increase in thylakoid membrane damage (13%) in the leaves of susceptible cultivars under HNT stress. Similarly, the susceptible cultivars also recorded significant reduction in biomass (34%), pod number (22%), pod weight (37%) and total seed weight (40%) per plant while the same set of agronomic traits were not affected among the tolerant cultivars. Quantitative impact of heat stress was confirmed with increased sensitivity to HNT exposure from gametogenesis until maturity resulting in a significantly higher yield loss compared to stress exposure from post-flowering till maturity. HNT significantly decreased oil concentration, but increased protein concentration and saturated fatty acid levels in seeds of the susceptible cultivars. However, HNT had no impact on the unsaturated fatty acids in both hybrids and the open-pollinated cultivars. Breeding targets based on fatty acid composition for enhancing canola seed quality may not be easily amenable due to the inconsistency documented with the compositional changes under heat stress. In summary, our findings conclude that canola hybrids are better suited to regions experiencing heat stress, compared to open-pollinated cultivars, indicating the possibility of a complete shift to hybrid canola cultivation under predicted hotter climates in the future.     

Performance of CERES-Rice and CERES-Wheat models in rice–wheat systems: A review

Rice–wheat (RW) systems are critical to food security and livelihoods of rural and urban poor in south Asia and China, and to regional economies in southeast Australia. The sustainability of RW systems in south Asia is, however, threatened by yield stagnation or decline, and declining partial factor productivity, soil organic C and water availability. Crop models potentially offer a means to readily explore management options to increase yield, and to determine trade-off between yield, resource-use efficiency and environmental outcomes. This paper reviews the performance of CERES-Rice and CERES-Wheat in Asia and Australia in relation to their potential application towards increasing resource use efficiency and yield of RW systems.

The performance of the models was evaluated using simulated and observed data on anthesis and maturity dates, in-season LAI and growth, final grain yield and its components, and soil water and N balances from published studies across Asia and Australia, and then by computing the statistical parameters for the major characters. Over the four data sets examined for anthesis and six for maturity dates, CERES-Rice predicted those dates fairly well (normalised RMSE = 4–5%; D-index = 0.94–0.95), but over the 11 sets for grain and 4 for biomass yield, the predictions were more variable (normalised RMSE = 23% for both; D-index 0.90 and 0.76, for grain and biomass, respectively). Model performance was poorer under conditions of low N, water deficit, and low temperatures during the reproductive stages. Over the three data sets examined, CERES-Wheat predicted the anthesis and maturity dates quite well (normalised RMSE = 4–5%; D-index = 0.94–0.99), and over eight sets for grain and two sets for biomass yield the model predicted them also reasonably well (RMSE = 13–16%; D-index = 0.86–0.97). Only one study evaluated the DSSAT RW sequence model with fairly satisfactory predictions of rice and wheat yields over 20 years with adequate N, but not the long-term change in soil organic C and N. Predictions of in-season LAI and crop growth, and soil and water processes were quite limited to investigate the robustness of model processes.

Application of models to evaluate options to increase water and N use efficiency requires the ability to perform well at the margin where deficit stress begins. While both models generally perform satisfactorily under water and N non-limiting conditions, the little evidence available suggests that they do not perform well under resource-limiting situations. We recommend that the models’ key processes under the water and N limiting conditions be further evaluated urgently. The DSSAT sequence model also needs to be further evaluated against observations for a range of locations and management using data from long-term experiments in RW systems.     

New strategies for the elimination of polio from India

The feasibility of global polio eradication is being questioned as a result of continued transmission in a few localities that act as sources for outbreaks elsewhere. Perhaps the greatest challenge is in India, where transmission has persisted in Uttar Pradesh and Bihar despite high coverage with multiple doses of vaccine. We estimate key parameters governing the seasonal epidemics in these areas and show that high population density and poor sanitation cause persistence by not only facilitating transmission of poliovirus but also severely compromising the efficacy of the trivalent vaccine. We analyze strategies to counteract this and show that switching to monovalent vaccine may finally interrupt virus transmission.     

Relative efficiency of fungal intra‐ and extracellular phosphatases and phytase

A comparison of intra‐ and extracellular acid phosphatase, alkaline phosphatase and phytase activity in six fungi is reported. A strong linear relationship between intra versus extracellular fungal acid phosphatase (R² = 0.94), alkaline phosphatase (R² = 0.96), and phytase (R² = 0.97) is observed. Three‐fourth of acid phosphatase were generally present inside the fungal cells and only 25 % were released extracellularly after a three weeks period. Phytase shows the reverse trend where thirty nine times higher extracellular phytase activity was noticed than present inside the fungal cells. The extracellular enzymes are found 60 % more efficient in the hydrolysis of phytin than their intracellular counterpart but they are at par in the hydrolysis of glycerophosphate. The results clearly demonstrated that phytase types of phosphatases mostly occur outside the fungal cells whereas most of the acid phosphatase and alkaline phosphatase are located inside the cells.<?show $6#>     

Influence of integrated nutrient management (INM) on nutrient use efficiency,soil fertility and productivity of hybrid rice

A field experiment was conducted during the two consecutive kharif seasons of 2011 and 2012 on sandy-loam lateritic soil of Indian subtropics to investigate the impact of integrated nutrient management (INM) on crop productivity, nutrient use efficiency of applied nutrients and soil fertility in restoring sustainability with hybrid rice cultivation. Application of 50% recommended dose of fertilizer (RDF) + 50% recommended dose of nitrogen (RDN) through mustard oil cake (MOC) or 75% RDF + 25% RDN through MOC + biofertilizer recorded significantly higher grain and biomass yields, greater NPK removal and higher partial factor productivity of applied nutrient (PFPN) than those of the crop having 100% RDF, 100% RDN through MOC and 25% RDF + 75% RDN through MOC, which showed very poor performance. The former treatments also improved organic carbon and available NPK contents in soil in spite of greater removal of NPK by the crop. Results of study suggested integrated use of 50% RDF + 50% RDN through MOC or 75% RDF + 25% RDN through MOC + biofertilizer for increasing hybrid rice productivity, PFPN and improving soil fertility for sustainability.     

柠檬酸铜对肉鸡生产性能、血脂指标和组织胆固醇含量的影响

【目的】探讨柠檬酸铜对肉鸡生产性能、血脂指标和组织胆固醇含量的影响。【方法】采用单因子设计,将420只7日龄AA肉鸡随机分为7组,每组设3个重复,每个重复20只,公母各半。Ⅰ(对照)～Ⅶ组日粮分别添加0,50,100,150,200,250和300mg/kg柠檬酸铜,49日龄空腹称体质量,计算采食量、日增质量和料肉比。每组取6只鸡,采集血样、肝脏和胸腿肌,测定血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白(LDL-C)、极低密度脂蛋白(VLDL-C)和高密度脂蛋白(HDL-C)及肝脏、胸腿肌胆固醇含量。【结果】与Ⅰ组(对照)相比,Ⅳ～Ⅶ组肉鸡日增质量及日采食量均显著增加(P<0.05),料肉比显著降低(P<0.05);血清TC、TG、LDL-C、VLDL-C显著降低(P<0.05),HDL-C显著升高(P<0.05);胸腿肌、肝脏中的胆固醇含量显著降低(P<0.05);Ⅰ、Ⅱ、Ⅲ及Ⅳ、Ⅴ、Ⅵ、Ⅶ组间,以上指标差异均不显著(P>0.05)。【结论】日粮中添加150～300mg/kg柠檬酸铜,具有提高肉鸡生产性能、降低肉鸡血脂和组织胆固醇含量的效果。     

Comparative efficiency of acid phosphatase originated from plant and fungal sources

A study was conducted to demonstrate the comparative efficiency of acid phosphatase generated by plants or fungi towards the hydrolysis of different organic P compounds present in soil. The results revealed that acid phosphatases were most efficient in the hydrolysis of glycerophosphate followed by lecithin and phytin. The P release increased with increase in enzyme concentration. Acid phosphatase generated from fungal sources showed three times greater efficiency in the hydrolysis of phytin, two times greater efficiency in hydrolysis of lecithin than plant phosphatase. Both sources were at par in hydrolyzing glycerophosphate. The results suggest that acid phosphatase generated from plant and fungal sources is different and microbial acid phosphatase to be more efficient than that from plant sources.