Antioxidant and 15-lipoxygenase inhibitory activity of rotenoids, isoflavones and phenolic glycosides from Sarcolobus globosus

From Sarcolobus globosus, two rotenoids (villosinol and 6-oxo-6a,12a-dehydrodeguelin), one isoflavone (genistin) and four phenolic glycosides (vanillic acid 4-O-beta-d-glucoside, glucosyringic acid, tachioside and isotachioside) were identified for the first time from this species. Extracts and compounds from S. globosus were evaluated for their DPPH radical scavenging and 15-lipoxygenase (15-LO) inhibitory activities. All tested rotenoids were found to inhibit 15-LO, while they lacked DPPH radical scavenging effect.     

Methodological rigour in assessing participatory development

There have been few rigorous assessments of the effectiveness of participatory processes for natural resource management. In Bangladesh an approach known as Participatory Action Plan Development (PAPD) has been developed and applied. By combining problem identification and solution analysis by separate stakeholder groups with plenary sessions it is claimed to result in consensus and more effective community based management. Methodological issues in assessing the effectiveness of such development are discussed and good practice illustrated. Under the same project there were sites where PAPD had been used and others without its use so a comparative assessment could be made. However, for an appropriate assessment it is important to identify clear testable hypotheses regarding the expected benefits, appropriate measures, and other factors which may affect or confound the outcome. The paper illustrates how participatory assessment involving both individual opinions and focus groups can be systematically recorded, quantified and used with other data in statistical analysis. By using statistical modelling methods at an appropriate level of aggregation and controlling for other factors, benefits from PAPD were found to be significant. The systematic approaches and practices recommended from this example can be applied in similar situations to test the effectiveness of participatory processes using participatory assessments.     

Combined use of compost and wood scraps to increase carbon stock and improve soil quality in intensive farming systems

Intensive agricultural systems negatively affect soil quality principally because of a reduction in soil organic matter (OM). Sustainable practices providing organic amendments could be useful to maintain or increase OM content in agricultural soils, preserving and improving soil fertility. In this study, biomass with a large C:N ratio was applied to intensively farmed agricultural soils to maximize the increase of soil OM and hence chemical and biochemical fertility. In particular, 30 and 60 t ha^?1 of two mixtures of compost and scraps from poplar pruning, A1 and A2, with different C:N ratios (15 and 25, respectively), were applied to soils of two farms (F1 and F2) in a Mediterranean area (southern Italy) on an annual basis for two consecutive years. An effective, long‐lasting increase of soil OM, on average of 60 and 55% in F1 and F2 soils, respectively, was reached at the end of the experiment. As well as a progressive increase in the C:N ratio, total N and available P also increased with organic amendments, with positive effects on soil microbial activity as demonstrated by the enhancement of the seven studied enzymatic activities. Principal component analysis demonstrated different responses to various organic amendments between F1 and F2 soils because of their geopedological diversity. The results indicate that the C:N ratio of the mixture is an important factor, but what is the best rate of addition to use is still not obvious. The use of a smaller amount (30 t ha^?1) of the A1 mixture (10:1 compost:wood) appears, in these types of soils, to be the most suitable strategy to produce significant benefits.     

The potential of rice to offer solutions for malnutrition and chronic diseases

Elevated Na⁺ levels in agricultural lands are increasingly becoming a serious threat to the world agriculture. Plants suffer osmotic and ionic stress under high salinity due to the salts accumulated at the outside of roots and those accumulated at the inside of the plant cells, respectively. Mechanisms of salinity tolerance in plants have been extensively studied and in the recent years these studies focus on the function of key enzymes and plant morphological traits. Here, we provide an updated overview of salt tolerant mechanisms in glycophytes with a particular interest in rice (Oryza sativa) plants. Protective mechanisms that prevent water loss due to the increased osmotic pressure, the development of Na⁺ toxicity on essential cellular metabolisms, and the movement of ions via the apoplastic pathway (i.e. apoplastic barriers) are described here in detail.     

Systemic resistance to bacterial leaf speck pathogen in Arabidopsis thaliana induced by the culture filtrate of a plant growth-promoting fungus (PGPF) Phoma sp. GS8-1

The culture filtrate (CF) from the plant growth-promoting fungus Phoma sp. GS8-1 was found to induce systemic resistance in Arabidopsis thaliana against the bacterial leaf speck pathogen Pseudomonas syringae pv. tomato DC3000 (Pst), and the underlying mechanism was studied. Roots of A. thaliana were treated with CF from GS8-1, and plants expressed a clear resistance to subsequent Pst infection; disease severity was reduced, and proliferation of pathogen was suppressed. Various mutants of A. thaliana were used to test whether the CF induced resistance through one of the known signaling pathways: salicylic acid (SA), jasmonic acid (JA), and ethylene (ET). The CF was fully protective against Pst in Arabidopsis mutants jar1 and ein2 similar to wild-type plants. However, its efficacy was reduced in plants containing transgene NahG. Examination of systemic gene expression revealed that CF modulates the expression of SA-inducible PR-1, PR-2 and PR-5 genes, the JA/ET-inducible ChitB gene, and the ET-inducible Hel gene. Moreover, the expression of these genes was further enhanced upon subsequent stimulation after attack by Pst. Our data suggest that in addition to a partial requirement for SA, the signals JA and ET may also play a role in defense signaling in Arabidopsis.     

Associations of <Emphasis Type="Italic">NAM</Emphasis>-<Emphasis Type="Italic">A1</Emphasis> alleles with the onset of senescence and nitrogen use efficiency under Western Australian conditions

Wheat grain yield and protein content are significantly influenced by the onset of senescence and the duration of the grain filling phase. The onset of senescence also affects Nitrogen use efficiency (NUE) through interacting pathways involving N accumulation and translocation of N into the grains. The objective of this study was to relate variation in NUE and its components with two groups of the NAM-A1 gene alleles; (i) early onset of senescence in cultivars carrying the NAM-A1a allele, (ii) delayed onset of senescence in cultivars carrying the Non-NAM-A1a allele (b, c, d) in wheat cultivars grown under Western Australia conditions. A field trial was carried out over two seasons examining 19 cultivars under different N rates and time of N application. The Normalized Difference Vegetation Index was utilized to determine the onset of senescence after anthesis. The early onset of senescence results in high grain yield, harvest index, and NUE due to improvements in the N utilization ability. Accelerating the onset of senescence results in a short grain filling period leading to grain maturity before the onset of unfavourable summer conditions. The function of alleles of NAM-A1 gene in controlling senescence hence the NUE is highly regulated by environmental conditions. This study concluded that the function of NAM-A1a allele induces the onset of senescence with a positive effect on the NUE and its components under Western Australian conditions.     

反相高效液相色谱法测定有机氯及含氮杀虫剂在水体·土壤沉积物及鱼体中的残留

[目的]测定水体、土壤沉积物以及鱼体内有机氯及含氮杀虫剂残留物,为科学评估杀虫剂残留对巴基斯坦地区公共卫生、农业和环境的影响提供依据。[方法]以食用鱼南亚野鲮为材料,设计2组体重,采用高效液相色谱法分别测定水体、土壤沉积物以及南亚野鲮体内α-硫丹、DDE、甲基对硫磷、异丙隆、呋喃丹、阿特拉津等含量。[结果]土壤沉积物中DDE的含量达（2．340±0．025）μg／g,在250～750g的南亚野鲮体内的含量分别为（0．270±0．0006）μg／g,但在水体中未发现DDE残留;不同饲料中农药残留物90％为有机磷、呋喃丹以及有机氯杀虫剂,6％为杀菌剂,仅4％为除草剂,在250～750g以及800～1300g的南亚野鲮体内硫丹的含量分别达到（0．491±0．0006）μg／g和（3．050±0．0608）μg/g,异丙隆的含量分别达到（0．010±0．0003）μg／g和（0．014±0．0006）μg／g,且随体重上升,其脂肪含量增加,积累的农药残留物则越多;硫丹、甲基对硫磷、阿特拉津和呋喃丹的含量在水体达到最大残留限量水平0．001μg／g。[结论]通过生物积累和在自然界中的运输以及再沉积作用,有机氯及其他杀虫剂的使用给全球的环境造成了严重污染,因此,在巴基斯坦已经禁止使用DDT等有机氯农药。     

Weeds

Abstract

The effects of simulated rat damage (stem cutting) on IR-8 rice yield was examined. Fields were subjected to four damage levels: 0 (control), 10, 25 and 50% of the stems cut. A modified split-plot sampling design was used with ten 1 m² plots tested at each damage level in three growth stages: tillering, booting and maturity. Each of the 120 plots (2,400 hills) was harvested and yields compared by Analysis of Variance and Least Significant Difference (LSD) tests. Ten perpent of all stems removed during the tillering stage produced growth compensation and a higher yield resulted. Trends in rice yields for different damage levels showed that the later damage occurred, the greater the yield loss. An LSD analysis of yields for the damage levels revealed no significant differences during tillering. At booting, significant differences (P < 0.05) in yields were noted with > 10% of the stems cut. At maturity, yields for all damaged levels differed significantly (P < 0.01). The results of this study demonstrated that rat damage in rice up to the booting stage did not affect yield significantly. From an economic standpoint, rodent control by field baiting before booting stage is not recommended in monsoon rice.     

Association between line per se and hybrid performance under excessive soil moisture stress in tropical maize (Zea mays L.)

Excessive moisture (EM) stress during the summer–rainy season is one of the major production constraints for maize (Zea mays L.) in large areas of South and South-East Asia. A key question in breeding for tolerance to excessive moisture is the extent to which the performance of maize hybrids can be predicted on the basis of per se performance of inbred lines under excessive moisture. We attempted to identify the relationship between morpho-physiological traits and grain yield measured on inbred parents and their single cross progenies under EM stress. Responses of various morpho-physiological traits, except days to 50% anthesis, differ significantly under normal versus EM stress. Superiority of hybrid progenies over parental inbred lines increased under EM stress, suggesting that hybrids were comparatively more tolerant to EM stress than inbred progenies. Across moisture regimes, all morpho-physiological traits of hybrids, except lodging and root porosity under normal moisture, were found to be positively and significantly correlated with mid-parent traits. Our data suggest that per se performance of lines was a relatively more important factor in determining hybrid performance under EM stress, while under optimum soil moisture conditions mid-parent heterosis was relatively more important than per se performance of mid-parent. Phenotypic correlation between hybrid and mid-parent yields showed a strong relationship under EM stress (r = 0.66^**). The relationship was statistically significant under normal moisture as well, though it was comparatively weak (r = 0.41^*). Our findings suggest that performance of hybrid progenies under excessive moisture can be predicted and improved to some extent on the basis of their inbred parents that have been systematically selected and improved for EM stress.