小麦品种的耐盐性变化：甜菜碱和乙烯的作用

Four wheat (Triticum aestivum L.) cultivars 711, PBW343, 3765 and WH542 were screened for studying variations in glycinebetaine (GB) content and plant dry mass under 100 mmol L-1 NaCl stress. A tolerance index was calculated using plant dry mass data to select salt-tolerant and salt-sensitive types and find association between tolerance index and GB content. Tolerance index has been used as a good criterion to select the tolerant types under high salinity stress. Further, physiological differences in salt-tolerant cultivar 711 and salt-sensitive cultivar WH542 were examined. The salt-tolerant cultivar exhibited greater GB content, which was found correlative with ethylene. The cultivar also showed higher nitrogen (N) content and nitrate reductase activity, reduced glutathione and higher redox state resulting in maximal protection of plant dry mass than the salt-sensitive type. Thus, the content of GB may be considered as important physiological criteria for selecting salt-tolerant wheat types.     

The process of infection, migration, growth and development of Sanguinicola inermis Plehn, 1905 (Digenea: Sanguinicolidae) in carp, Cyprinus carpio L.

Abstract. Sanguinicoliasis is a serious disease of cultured carp causing high mortality in early fry. Experimental infections were used to study the pattern of penetration, and subsequent behaviour and development of the parasite. Maximum penetration of cercariae was achieved within 30 min, followed by a period of rapid development and growth marked by a doubling in length within the first 12 h. Subsequent growth was slower, during which major organ development took place, with gonadal maturity being completed between 60 and 90 days p.i. Penetration occurred mainly through the fins, particularly the caudal fin, and large numbers of worms remained in the skin where they continued to develop to maturity. A small proportion of the worms were found in the heart and gill vessels soon after infection. However, migration from the skin began at 60 days p.i. and greater numbers (57%) of the worms were found in heart and gill vessels at 90 days, coinciding with onset of egg production. Decline in worm numbers in the gill/heart region began after 120 days. Gill/heart worms differed in a number of features from skin worms, but egg production occurred simultaneously in both sites.     

Effect of Fruiting Branch/Square Removal on Growth and Quality of Bt Cotton under Different Potassium Rates

Removal of early fruiting branches with greater potassium doses caused more source and no sink at early stages of growth, leading to improved yield, yield components, and fiber quality traits in Bt cotton. The study used manual alteration of plant architecture (F₁, no branch removal; F₂, removal of first fruiting branch; F₃, removal of first and second fruiting branches; F₄, removal of all squares from first fruiting branch; F₅, removal of all squares from first and second fruiting branches) and potassium rates (50, 100, and 150 kg ha^?1) in a randomized complete block design and was repeated for 2 years (2011 and 2012). Increasing potassium application increased total bolls per plant and cotton yield to the greatest levels in F₃ and F₅, against lowest level in the control. Ginning out turn, fiber length, seed oil, and seed protein content were influenced by fruiting branch or square removal but the difference was less. Increasing potassium improved seed and fiber quality.     

Rumen parameters of yaks (Bos grunniens) and indigenous cattle (Bos taurus) grazing on the Qinghai‐Tibetan Plateau

Yaks and indigenous Qaidam cattle and cattle‐yak crosses (C × Y) graze on the Qinghai‐Tibetan Plateau (QTP) throughout the year, but yaks are raised at higher elevations than cattle. Yaks do not receive supplementary feed whereas cattle require supplementary feed during harsh winter. We hypothesized that yaks would cope with the severe conditions of the QTP better than cattle and utilize the pasture more efficiently. We also hypothesized that differences between species would be pronounced in winter, when conditions are particularly harsh. To test these hypotheses, seasonal rumen fluid parameters of yaks, C × Y and cattle (n = 3 for each) were examined. Rumen fluid was collected in summer and winter from each genotype 2, 5 and 12 hr after a day of grazing. Concentrations of total volatile fatty acid (VFA), acetate, propionate, isobutyrate and isovalerate were greater in yaks than in cattle in summer (p < 0.05), while propionate concentration was lower in yaks than in cattle in winter (p < 0.05). Concentrations of ammonia and urea were greater (p < 0.001) in yaks than in cattle (p < 0.001) in summer, whereas, concentrations of free amino acids (AA) were greater in cattle than in yaks in summer and winter (p < 0.001). Concentrations of total VFA, acetate, propionate and butyrate decreased linearly (p < 0.05), whereas concentrations of isobutyrate and isovalerate increased linearly for yak and C × Y with sampling time (p < 0.05) in summer. In summer, concentrations of isobutyrate and isovalerate were greater in yaks than in cattle (p < 0.05). In conclusion, rumen fermentation characteristics of yaks showed that they coped better than cattle or C × Y in the harsh climate as we hypothesized. However, in contrast to our hypothesis, this emerged only in summer, when pasture was plentiful and not in winter, when pasture was scarce.     

Crop photosynthetic response to light quality and light intensity

Under natural conditions, plants constantly encounter various biotic and abiotic factors, which can potentially restrict plant growth and development and even limit crop productivity. Among various abiotic factors affecting plant photosynthesis, light serves as an important factor that drives carbon metabolism in plants and supports life on earth. The two components of light(light quality and light intensity) greatly affect plant photosynthesis and other plant's morphological, physiological and biochemical parameters. The response of plants to different spectral radiations and intensities differs in various species and also depends on growing conditions. To date, much research has been conducted regarding how different spectral radiations of varying intensity can affect plant growth and development. This review is an effort to briefly summarize the available information on the effects of light components on various plant parameters such as stem and leaf morphology and anatomy, stomatal development, photosynthetic apparatus, pigment composition, reactive oxygen species(ROS) production, antioxidants, and hormone production.     

Physiological and Molecular Analysis of Applied Nitrogen in Rice Genotypes

Ten genotypes of rice (Oryza sativa L.) were grown for 30 d in complete nutrient solution with 1 mmol/L (N-insufficient),4 mmol/L (N-moderate) and 10 mmol/L (N-high) nitrogen levels,and nitrogen efficiency (NE) was analyzed.Growth performance,measured in terms of fresh weight,dry weight and lengths of root and shoot,was higher in N-efficient than in N-inefficient rice genotypes at low N level.Of these 10 genotypes,Suraksha was identified as the most N-efficient,while Vivek Dhan the most N-inefficient.To find out the physiological basis of this difference,the nitrate uptake rate of root and the activities of nitrate assimilatory enzymes in leaves of N-efficient and N-inefficient rice genotypes were studied.Uptake experiments revealed the presence of two separate nitrate transporter systems mediating high-and low-affinity nitrate uptake.Interestingly,the nitrate uptake by the roots of Suraksha is mediated by both high-and low-affinity nitrate transporter systems,while that of Vivek Dhan by only low-affinity nitrate transporter system.Study of the activities and expression levels of nitrate assimilatory enzymes in N-efficient and N-inefficient rice genotypes showed that nitrate reductase (NR) and glutamine synthetase (GS) play important roles in N assimilation under low-nitrogen conditions.     

Effect of ambient management interventions on the production and physiological performance of lactating Sahiwal cattle during hot dry summer

During summer season, increase in the environmental temperature in the subtropical regions of Pakistan is negatively affecting the performance of dairy animals. The study objective was to determine the effect of ambient management (90 days) on productive and physiological performance of lactating Sahiwal cows during hot dry summer season. Fifteen lactating cows during the early lactation stage, having similar parity (3), daily milk production (6.2 l), were randomly allocated to three treatments, 5 cows each, i.e., (1) kept under roof shade only, (2) provision of fans along with roof shade, and (3) provision of roof shade, fans, and sprinklers designated as S, SF, and SFS, respectively. The fans were of 360-rpm capacity and showers were on for 40 min after every 90-min interval from 9:00 to 21:00 h. THI values were 81.1?±?0.7, 80.5?±?0.7, and 77.7?±?0.4 under S, SF, and SFS treatments, respectively. Cows were milked twice daily. Respiration rate (RR) and rectal temperature (RT) data were collected at 14:00 h on daily basis. The daily milk production was significantly higher in cows under SF (7.9?±?1 kg) followed by SFS (6.9?±?1.2 kg) and S (6.1?±?0.9 kg) treatments. The mean RT (101.0?±?0.04 °F) was significantly lower in cows under SFS than that on SF and S treatments and similarly mean RR was also lower (21.2 breaths/min) in cows under SFS followed by SF and S treatments. It is concluded that milk production and physiological performance in Sahiwal cows can be improved by fan-assisted ventilation during hot dry summer in subtropical regions.     

Estimation of the total gaseous nitrogen losses from clay soils under laboratory and field conditions

Acetylene blockage was evaluated as a method for measuring losses of N₂O + N₂ from two Denchworth series clay soils. The denitrification potential in anaerobic, dark incubations at 20°C with nitrate (equivalent to 100 kg N ha^?1 0–20 cm depth), maximum water holding capacity, and acetylene (1%), was equivalent to 32 ± 11 and 39 ± 6 kg N ha^?1 per day for the two 0–20 cm soils and was positively correlated with carbon content (r= 0.98). After 4 days N₂O was reduced to N₂ in the presence of C₂H₂. In April 1980 following irrigation (24 mm) and applications of ammonium nitrate (70 kg N ha^?1) and acetylene, the mean nitrous oxide flux from soil under permanent grass was 0.05 ± 0.01 kg N₂O-N ha^?1 per day for 8 days. In June 1980, the losses of nitrogen from cultivated soils under winter wheat after irrigation (36 mm) and acetylene treatment were 0.006 ± 0.002 and 0.04–0.07 ± 0.01 kg N ha^?1 per day respectively before and after fertilizer application (70 kg N ha^?1). The nitrous oxide flux in the presence of acetylene decreased briefly, indicating that nitrification was rate determining in drying soil.     

Effects of Sanguinicola inermis Plehn, 1905 (Digenea: Sanguinicolidae) infection on growth performance and mortality in carp, Cyprinus carpio L.

Abstract. Outbreaks of sanguinicoliasis have been reported from several carp, Cyprinus carpio L., farms in Britain since 1978. The parasitic agent, Sanguinicola inermis Plehn, 1905, affects young of the year carp in nursery ponds. In the outbreak studied mortality as high as 90% occurred within the first 2–3 months of life. The prevalence of infection in surviving fish was 74% and their growth performance was measured over a period of 16 weeks under optimum aquarium conditions. The fish showed a poor growth performance with depressed specific growth rates and daily live weight gain. Food utilization, food conversion rates and protein efficiency ratios were inferior in both lightly and heavily infected groups of fish. A further 30% mortality occurred in the heavily infected group during the experiment, 14 months after the initial infection, indicating serious long-term effects of the parasite. There appears to be little value in retaining infected fish and complete destruction of affected stocks and disinfection of the farm is recommended where possible.     

Physiological and biochemical appraisal for mulching and partial rhizosphere drying of cotton

Water is the main factor for the healthy life of plant. One of the main negative effects of climate change is the increasing scarcity of water that is lethal for plant. Globally, for water deficit regions(arid and semi-arid), drought is the main factor responsible for low production of agriculture, especially for cotton. Great efforts have been and are being made to find alternatives to water saving practices. This study aimed to examine the effects of partial rhizosphere drying(PRD, half of the root system irrigated at one event, and the other half irrigated in the next event, and so on) with and/or without various mulching treatments on physiological and biochemical traits of cotton. To explore this objective, we laid out experiments in completely randomized design with factorial arrangement in the Islamia University of Bahawalpur, Pakistan in 2016. Two factors included were four mulching treatments(M_0, no mulching; M_1, black plastic mulching; M_2, wheat straw mulching; and M_3, cotton sticks mulching) and two irrigation levels(I_0, control(full irrigation); and I_1, PRD). Fisher's analysis of variance among means of treatments was compared using least significant difference test at 5% probability level. Results revealed that the maximum plant height, leaf area, leaf gas exchange(photosynthetic rate and stomata conductance), chlorophyll, proline and total sugar contents, and enzyme activities were higher under M_2 than under other three mulching treatments. As for irrigation levels, higher values of plant height, photosynthesis and water related parameters(leaf water potential, leaf osmotic potential, leaf turgor potential, etc.) were recorded. Contents of total sugar and proline and activities of antioxidant enzymes were significantly higher in PRD-treated plants than in control plants. It was concluded that combined application of PRD and mulching was more effective than the rest of the treatments used in the experiment. Similar study can be conducted in the field by applying irrigation water in alternate rows in semi-arid regions.