Salt-induced perturbation in growth,physiological attributes,activities of antioxidant enzymes and organic solutes in mungbean (Vigna radiata L.) cultivars differing in salinity tolerance

A pot experiment was conducted to appraise the inhibitory effects of salt stress on biochemical attributes in the three mungbean cultivars (NCM-209, NCM-89 and NM-92). Salt stress caused a significant decrease in plant height, shoot relative water contents, photosynthetic pigments, endogenous levels of K⁺ and K⁺/Na⁺ ratios and increase in cellular levels of H₂O₂, MDA, Na⁺ and Cl^?. However, cv. NCM-209 was found to be tolerant in terms of lower salt-induced decline in K⁺, K⁺/Na⁺ ratio and photosynthetic pigments. The endogenous levels of H₂O₂ and MDA were also lower in cv. NCM-209. Salt stress markedly also affected different yield attributes in all mungbean cultivars. Again cultivar NCM-209 exhibited less inhibitory effects of salt stress on different growth attributes. Salt stress resulted in a marked increase in the activities of antioxidant enzymes (superoxide dismutase, peroxidase, catalase and ascorbate peroxidase) in mungbean cultivars. Activity of peroxidase was maximal in cv. NCM-209 and catalase activity was maximal in cv. NCM-89, whereas cvs. NCM-89 and NM-92 showed higher activities of superoxide dismutase. Similarly activity of ascorbate peroxidase was higher in cv. NM-92. It could be inferred from data of antioxidant enzymes that mungbean cultivars cannot be categorized as salt tolerant or sensitive on the basis of a single antioxidant enzyme.     

开都河下游绿洲农田土壤微量元素污染及潜在健康风险评价

从新疆开都河下游绿洲农田土壤采集98个土壤样品,测定其中As、Cd、Cr、Cu、Ni、Pb和Zn的含量,利用地累积指数(I_(geo))评价农田土壤污染水平,采用US EPA健康风险评价模型,对农田土壤微量元素污染的潜在健康风险进行评估。结果表明,研究区农田土壤中Zn呈现轻度污染,Cd与Pb呈现轻微污染,As、Cr、Cu与Ni呈现无污染态势。研究区农田土壤中7种微量元素在3种暴露途径下成人和儿童的潜在非致癌风险商(HQ)从大到小依次为HQ_(Pb)HQ_(As)HQ_(Cr)HQ_(Cd)HQ_(Cu)HQ_(Ni)HQ_(Zn);HQ与潜在非致癌风险指数(HI)均小于1,属于可接受风险水平,微量元素对儿童的HI略小于成人。As和Cd在3种暴露途径下成人和儿童的单项致癌风险指数CR_(As)大于CR_(Cd)。CR与总致癌风险指数(TCR)均小于10-4,属于可接受风险水平;微量元素对儿童的潜在致癌风险略高于成人。研究区农田土壤中As、Cr与Pb是最主要的潜在非致癌风险因子,As是最主要的潜在致癌风险因子。     

Gross protein value units in the standardisation of rations for Fayoumi chicks

For the standardisation of rations for Fayoumi chicks, gross protein value unit (G.P.V.U.) was introduced; this was taken to mean the amount of supplementary protein that would stimulate as much growth as 3 per cent casein protein having gross protein value of 100.

Three total protein levels were tested in diets containing the same productive energy levels (1800kcal./kg.) and G.P.V.U.’s (30 per kg. of food). Since no significant differences in chick growth were recorded up to 8 weeks of age it was concluded that it is practical to adjust the energy :protein ratio between productive calories and G.P.V.U.’s per kg. of food irrespective of the total protein in the diets of growing Fayoumi chicks.     

Distinct association of an alphasatellite and a betasatellite with <Emphasis Type="Italic">Tomato leaf curl New Delhi virus</Emphasis> in field-infected cucurbit

Leaf samples of Cucurbita pepo with yellow mosaic disease symptoms were collected in 2012. Rolling circle amplification and PCR amplification with begomovirus-specific primers confirmed the presence of an Old World bipartite begomovirus, an alphasatellite and a betasatellite. Molecular analysis of full-length sequences showed that Tomato leaf curl New Delhi virus (DNA-A) is associated with its cognate DNA-B, Papaya leaf curl betasatellite and a novel alphasatellite. To the best of our knowledge, this is the first report of an alphasatellite and a betasatellite associated with a bipartite begomovirus.     

Effect of species grouping and site variables on aboveground biomass models for lowland tropical forests of the Indo-Malay region

Key message

This study assessed the effect of ecological variables on tree allometry and provides more accurate aboveground biomass (AGB) models through the involvement of large samples representing major islands, biogeographical zones and various succession and degradation levels of natural lowland forests in the Indo-Malay region. The only additional variable that significantly and largely contributed to explaining AGB variation is grouping based on wood-density classes.

Context

There is a need for an AGB equation at tree level for the lowland tropical forests of the Indo-Malay region. In this respect, the influence of geographical, climatic and ecological gradients needs to be assessed.

Aims

The overall aim of this research is to provide a regional-scale analysis of allometric models for tree AGB of lowland tropical forests in the Indo-Malay region.

Methods

A dataset of 1300 harvested trees (5 cm ≤ trunk diameter ≤ 172 cm) was collected from a wide range of succession and degradation levels of natural lowland forests through direct measurement and an intensive literature search of principally grey publications. We performed ANCOVA to assess possible irregular datasets from the 43 study sites. After ANCOVA, a 1201-tree dataset was selected for the development of allometric equations. We tested whether the variables related to climate, geographical region and species grouping affected tree allometry in the lowland forest of the Indo-Malay region.

Results

Climatic and major taxon-based variables were not significant in explaining AGB variations. Biogeographical zone was a significant variable explaining AGB variation, but it made only a minor contribution on the accuracy of AGB models. The biogeographical effect on AGB variation is more indirect than its effect on species and stand characteristics. In contrast, the integration of wood-density classes improved the models significantly.

Conclusion

Our AGB models outperformed existing local models and will be useful for improving the accuracy on the estimation of greenhouse gas emissions from deforestation and forest degradation in tropical forests. However, more samples of large trees are required to improve our understanding of biomass distribution across various forest types and along geographical and elevation gradients.

     

Assessing the critical factors affecting the viability of small-scale dairy farms in the Punjab region of Pakistan to inform agricultural extension programmes

Agriculture in the Punjab province of eastern Pakistan benefits from one of the largest canal irrigation systems in the world. The typical mixed holding is a small, 5 ha mixed farm with three-quarters of its land used for cash crops, such as rice, wheat and sugarcane, and the remainder growing forages such as lucerne and berseem for dairy animals. Both cows and buffaloes are used for milk production, with the latter the more productive. Despite irrigation, productivity is constrained by a slow uptake of new technology such as fertilisers and new plant varieties, and poor livestock management, which leads to extended calving intervals, and a lack of available capital. This study used LP models, constructed with original local data on milk and crop production activities, to investigate the effect on profitability of alleviating the main constraints. The results demonstrate the powerful effect of using better, well managed dairy livestock, of increasing the uptake of simple technological improvements and of widening access to credit. They also show the synergy between these elements, for example the importance of finance as part of any intervention strategy. The results should enable agricultural development policy makers to rank the changes and devise better targeted programmes to deliver the changes on farm.     

Initial results from the Mini-TES experiment in Gusev Crater from the Spirit Rover

The Miniature Thermal Emission Spectrometer (Mini-TES) on Spirit has studied the mineralogy and thermophysical properties at Gusev crater. Undisturbed soil spectra show evidence for minor carbonates and bound water. Rocks are olivinerich basalts with varying degrees of dust and other coatings. Dark-toned soils observed on disturbed surfaces may be derived from rocks and have derived mineralogy (+/-5 to 10%) of 45% pyroxene (20% Ca-rich pyroxene and 25% pigeonite), 40% sodic to intermediate plagioclase, and 15% olivine (forsterite 45% +/-5 to 10). Two spectrally distinct coatings are observed on rocks, a possible indicator of the interaction of water, rock, and airfall dust. Diurnal temperature data indicate particle sizes from 40 to 80 microm in hollows to approximately 0.5 to 3 mm in soils.     

Wheat grain yield,phosphorus uptake and soil phosphorus fraction after 23 years of annual fertilizer application to an Andosol

A field experiment was conducted on an Andosol to evaluate wheat (Triticum aestivum L.) yield, P and N uptake and soil P fraction after long-term fertilization (no fertilizer, NPK, NP, NK and PK treatments). Application rates of N, P and K fertilizers were 100, 65 and 83 kg ha⁻¹ year⁻¹ by ammonium sulfate, superphosphate, and potassium chloride, respectively. Phosphorus fertilization was critical for grain yield since the NK treatment did not increase yield compared with no fertilizer treatment. Agronomic efficiency of P was greater than agronomic efficiency of N, although apparent recovery of P and N were 17 and 53%, respectively. Combination application of fertilizer P and N resulted in the greatest grain yield over 23-year cultivation. Interaction impact on grain yield between P and N ranged from 71 to 109%, and was greater than the values for cereals in the earlier works. The N/P ratios of wheat decreased by P application and increased by N application. The N/P ratios in NPK and NP treatments were higher than the values attaining maximum yield for cereal crops reported by other works.     

焉耆盆地小麦地土壤重金属污染及生态风险

从新疆焉耆盆地采集35个小麦地土壤样品,测定其中As、Cd、Cr、Cu、Mn、Ni、Pb和Zn 8种重金属元素的含量,采用内梅罗污染指数(NPI)、潜在生态风险指数(RI)和生态风险预警指数(IER)对小麦地土壤重金属污染及生态风险进行评价。结果表明:焉耆盆地小麦地Cd含量平均值超出国家土壤环境质量二级标准的11.12倍,Cd、Cr、Ni、Pb和Zn含量的平均值分别超出新疆灌耕土背景值的55.58、1.32、1.48、3.21倍和4.47倍。小麦地Cd、Pb和Zn呈现重度污染,Cr和Ni轻度污染,As和Cu轻微污染,Mn无污染;研究区NPI平均值为7.93(呈现重度污染状态),RI平均值为342.95(属于较强生态风险水平),IER平均值为5.68(属于重警级别),土壤RI和IER从研究区北向南部呈现逐渐增加趋势。小麦地Ni、Pb与Zn主要受到人为污染源的影响,Cu、Mn和Cr主要受到土壤地球化学特征的控制,As和Cd可能受人为污染和自然因素共同影响。综上认为,Cd是焉耆盆地小麦地主要的污染因子和生态风险因子,对研究区耕地Cd污染应予关注。     

新疆绿洲区不同灌溉方式及灌溉量下苜蓿田间土壤水分运移特征

为探讨新疆绿洲区不同灌溉方式及灌溉量对苜蓿田间土壤水分空间分布及运移的影响,在苜蓿生长第二年设滴灌和漫灌两种灌溉方式,每种灌溉方式设3个灌溉梯度,对土壤含水量进行了测定与分析。结果表明,苜蓿生长季内,随生育进程的推进及灌水次数的增加,土壤水分含量呈波动式递减变化趋势。灌溉后垂直方向上0~40cm、水平方向上0~30cm土层土壤含水量明显增加,且垂直方向上土壤水分湿润峰明显大于水平方向。苜蓿整个生育期随灌水量及收获茬次的增加,水分利用效率逐渐下降。滴灌和漫灌水分利用效率分别为4.55~5.48kg/(mm·hm2)、3.21~3.81kg/(mm·hm2),与漫灌相比,滴灌方式总水分利用效率提高了42%~44%。当滴灌灌溉量为3000m3/hm2、漫灌为5250m3/hm2时,苜蓿生产的综合经济效益最好。