Effect of rhizosphere microbiome on different crop growing fields in various rice cultivars and its molecular approaches for sustainable agro-ecosystem

Journal of Crop Science and Biotechnology - The present investigation was carried out to investigate the effects of rhizosphere bacteria on growth and rice yields. Also, isolation and...     

小麦脱植基相关基因在春性小麦叶片叶绿素降解过程中的作用分析

小麦叶片的衰老会导致产量的损失,而叶绿素降解是小麦叶片衰老的明显特征,分析小麦叶绿素降解过程中脱植基反应的相关基因叶绿素酶（TaCLH）和脱镁叶绿素水解酶（TaPPH）在春性小麦叶片衰老过程中的作用,为解析小麦叶绿素降解的分子机制提供参考。以10个春性小麦品种为参试材料,对衰老过程中TaCLH和TaPPH的相对表达量进行测定,结合不同品种在开花后不同时期的相对叶绿素含量（SPAD）、功能绿叶面积（GLAD）和叶绿素荧光参数的变化规律,研究叶片衰老过程中TaCLH和TaPPH与SPAD、GLAD和叶绿素荧光参数的相关关系。结果表明,TaPPH的相对表达量与GLAD、SPAD及叶绿素荧光参数[ETR、F_v/F_m、Y(Ⅱ)]等生理指标之间存在极显著负相关关系,与TaCLH相对表达量存在极显著正相关关系,表明TaPPH在春小麦叶绿素降解过程的脱植基反应中起主要作用。     

Preservation of Disease-free Shoot Tips of Potato Germplasm through in vitro System

In vegetatively propagated crops,once system ati-cally infected w ith a viral disease,the pathogen canpassed from one generation to the next[1].Especially inpotato,contam ination by a pathogen can severely re-duce the total yield of the crop[2].Traditionally,potatovarieties have been and still m aintained in a fieldgene bank.M aintenance of potato germ plasm in thefield is a m ajor consum er of tim e,m anpower andspace aside from diseases and environm ental stresses.The m ajor disadvantage of …     

Localization of Vesicular Glutamate Transporter 2 mRNA in the Dorsal Root Ganglion of the Pigeon (Columba Livia)

Our previous study showed localization of glutamate receptor 1 (GluR1) mRNA in neurons of the pigeon spinal cord, suggesting glutamatergic input from intrinsic and extrinsic origins. The present study examined localization of vesicular glutamate transporter 2 (VGLUT2) mRNA to confirm an extrinsic origin of glutamatergic neurons in the dorsal root ganglion (DRG). GluR1 and GluR2 mRNAs were examined in DRG and spinal cord to seek projection regions from VGLUT2 mRNA‐expressing neurons. VGLUT2 mRNA was expressed in most DRG neurons and labelling intensity varied from weakly to intensely. Intense VGLUT2 mRNA expression was mainly seen in medium to large neurons. GluR1 and GluR2 mRNAs were expressed in the dorsal horn and GluR2 mRNA signal was also seen in the marginal nucleus. The results suggest that the pigeon DRG has an extrinsic glutamatergic origin that project to the dorsal horn and marginal nucleus of the spinal cord.     

Isolation of a fertile wheat-barley addition line carrying the entire barley chromosome 1H

The isolation of six of the seven possible additions of barley chromosomes to the wheat genome reported 18 years ago has made an important contribution to gene mapping in barley, first with genes controlling isozymes and more recently DNA (molecular) markers. A fertile addition line involving barley chromosome 1H,which carries genes controlling several characters of economic importance, could not be isolated at that time because it caused extreme meiotic abnormalities leading to complete sterility when added to wheat. Later the short arm of barley chromosome 1H was added to wheat as a fertile ditelosomic addition, but the non-availability of the entire barley chromosome 1H addition line has hampered the location of barley genes to the long arm of this chromosome. This problem has now been overcome cytogenetically as described herein. The resultant self-fertile disomic-monotelodisomic addition line carrying a pair of barley chromosome 6H and a heteromorphic 1H/1HS pair is more stable, and makes the wheat-barley addition line series complete for gene mapping work and will provide a vehicle for the possible transfer of useful genes from this barley chromosome to wheat.     

Pests of Deepwater Rice and their Management

Deepwater rice has a distinctive pest complex due to prolonged deep flooding, extended growth duration and a complex environment. Flooding smothers weeds, prevents population buildups of some pests and diseases, and stimulates new growth which may compensate for early damage. Major pests are adapted to these aquatic conditions and exploit the succulent growth and mild weather extremes of this period.In Asia, yellow stem borer causes widespread damage by producing a loss of bearing stems, and lighter or empty panicles. No appropriate measures are known and control of this major pest is a daunting challenge. Stem nematode severely damages rice in several areas but varietal resistance is effective. Rats and hispa beetle are also injurious and many lesser pests are known. In West Africa's smaller Deepwater rice area, stem borers, leafeaters, birds and rats are damaging but their effect on yield is obscure. Farmers commonly employ cultural control methods, and insecticides are used in some areas but diseases are not treated. Pesticide use is restricted by application difficulties, contamination concerns and the low value of the crop. In Asia and Africa wild rices, grasses and sedges compete fiercely with rice before flooding; herbicides are not generally used but many farmers hand weed though the extent of yield loss is poorly understood.Pest management research in deepwater rice is difficult because of the nature of the agroecosystem. Most research has been carried out in Asia but the volume has seriously declined over the last decade.     

Effect of time-restricted feeding and refeeding regimes on compensatory growth,body composition,and feed utilization in prawn (Macrobrachium rosenbergii) culture system

ABSTRACT

A 14-week feeding experiment was conducted to determine the effect of a time-restricted feeding and refeeding regime on compensatory growth, body composition, and feed utilization in improved traditional prawn (Macrobrachium rosenbergii) culture systems. Three groups of prawn were used in which the control group (C) received feed regularly at ad libitum and the other two groups, Treatment 1 (T₁) and Treatment 2 (T₂), consumed feed 4 and 5 days per week respectively throughout the first 9 weeks. After feeding restriction, satiation of feed was given in the last 5 weeks. At the end of the experiment, the final weight of prawn in C, T₁, and T₂ were found to be 17.23 ± 6.56g, 16.04 ± 6.18g, and 15.64 ± 6.34 g respectively, which was insignificant. FCR decreased with increased restriction of feeding, while PER and NPU increased. Moisture content increased significantly, while protein and lipid content decreased significantly with increasing restriction time of feeding. After the satiation period, only the T2 group was able to replenish the lipid content. Water quality parameters didn’t vary significantly among the experimental groups and remained within optimum level. Therefore, time restriction could be applied in Macrobrachium rosenbergii culture without detrimental effects on growth, feed efficiency, and nutrient utilization.     

Elevated temperature affects growth and hemato‐biochemical parameters,inducing morphological abnormalities of erythrocytes in Nile tilapia Oreochromis niloticus

Temperature is considered as an important environmental factor, and the increasing water temperature resulting from global warming is a great concern. The present study was conducted to examine the effects of elevated water temperature on growth, hemato‐biochemical parameters in Nile tilapia, Oreochromis niloticus acclimatized to three temperatures (31°C, 34°C and 37°C) for 60 days. Additionally, erythrocytic cellular abnormalities (ECA) and erythrocytic nuclear abnormalities (ENA) tests were assayed using peripheral erythrocytes after exposure to the three temperatures. Fish were sacrificed on days 7, 15, 30 and 60 of exposure. Growth performances viz., weight gain, % weight gain and specific growth rate (SGR) showed decreasing tendency at 34°C but significantly declined at 37°C compared to 31°C. The abundance of haemoglobin (Hb) and red blood cells (RBCs) significantly decreased in response to temperature increases, while white blood cells (WBCs) displayed the opposite response. At days 7 and 15, blood glucose levels significantly increased in response to the temperature increase, while at days 30 and 60 glucose declined. Frequencies of ECA and ENA were significantly enhanced at the highest temperature throughout the experimental period. Dissolved oxygen decreased and free CO₂ increased significantly with increasing temperature throughout the study period. The present study revealed that temperatures higher than 34°C may be hazardous to O. niloticus.     

Deforestation effects on vegetative regeneration and soil quality in tropical semi‐evergreen degraded and protected forests of Bangladesh

Tropical forests of the world are degrading at an alarming rate because of human‐induced activities. This study was conducted to determine the consequences of deforestation on the natural regeneration of vegetation and soil quality in tropical, semi‐evergreen protected and degraded forest ecosystems of Bangladesh. In each forest ecosystem, 20 matured trees were randomly selected for laid‐out experimental plots by placing the tree stand at the center of the plot. The number of vegetative species, height, basal area, crown percentages and species richness were measured. The selected soil properties were determined. The vegetation in the protected forest site was denser with an abundance of species than in the degraded forest site. The primary forest regenerative species were dominated by the dipterocarps in both forest sites. The most alarming difference was that of an abrupt decline in regenerative forest species accompanied by an increase in exotic shrubs, grasses and vines typical of open habitats in the degraded forest site. These shrubs (e.g. Melastaoma, Lantana camara, Clerodendrum infortunatum and Jasminium spp.) and grasses and vines (e.g. Imperata cylindrica, Imperata arundinacea, Mikania scandenes, Saccharum spontaneum and Eupatorium odoratum) are gradually replacing the primary forest regenerative species in the degraded forest site. The soil quality of the degraded forest site has deteriorated over time due to preferential removal of finer particles and organic matter by accelerated water erosion. As a result, natural regeneration of primary forest species, especially dipterocarps, is severely affected by the direct effects of biotic interferences and attendant processes of soil quality degradation from deforestation. In contrast, degraded forest sites under regular protection have shown slow, but gradual, increase in crown frequency, enhanced recruitment and recovery of primary forest species, species abundance, and an improvement in soil quality. Copyright © 2001 John Wiley & Sons, Ltd.     

Synergistic effects of quaternary ammonium compounds and food additive grade calcium hydroxide on microbicidal activities at low temperatures

The microbicidal activities of mixtures of quaternary ammonium compounds (QACs) and food additive grade calcium hydroxide (FdCa(OH)₂) were evaluated in a suspension test at −20°C using an anti-freeze agent (AFA) containing methanol, or at 1°C, with varying contact time, toward avian influenza virus (AIV), Newcastle disease virus (NDV), fowl adenovirus (FAdV), avian reovirus (ARV), Salmonella Infantis (SI) and Escherichia coli (EC). At −20°C, the mixtures could inactivate AIV and NDV within 30 min, FAdV and ARV within 5 sec, and SI and EC within 3 min, respectively. AFA did not inactivate viruses and bacteria within 30 min and 10 min, respectively. At 1°C, the mixtures inactivated FAdV and ARV within 30 sec, AIV within 10 min, and NDV within 30 min. A mixture of slaked lime (SL) and QAC could inactivate FAdV and ARV within 30 sec, but could not inactivate AIV and NDV even after 60 min at 1°C. SL could not substitute FdCa(OH)₂ in order to exert the synergistic effects with QAC. Thus, QACs microbicidal activities were maintained or enhanced by adding FdCa(OH)₂. It is hence recommended to use QACs with FdCa(OH)₂, especially in the winter season.