Salicylic acid-induced physiological and biochemical changes in lemongrass varieties under water stress

Abstract

Salicylic acid (SA) treatment reduces the damaging action by water deficit on growth and accelerates a restoration of growth processes. The aim of the present work was to study the physiological and biochemical alteration induced by SA in lemongrass plants under stress conditions. Therefore, a pot culture experiment was conducted to test whether SA application at concentration of (10^?5 M) through foliar spray could protect lemongrass (Cymbopogon flexuosus Steud. Wats.) varieties (Neema and Krishna), subjected to drought stress on the basis of growth parameters and biochemical constituents, proline metabolism and quality attributes including citral content. The treatments were as follows: (i) 100% FC + 0 SA; (ii) 75% FC + 0 SA; (iii) 50% FC + 0 SA; (iv) 75% FC + 10^?5 M SA; and (v) 50% FC + 10^?5 M SA. The growth parameters were significantly reduced under the applied water stress levels; however, foliar application of salicylic acid (10^?5 M) improved the growth parameters in stress-affected plants. The plants under water stress exhibited a significant increase in activities of nitrate reductase and carbonic anhydrase, and electrolyte leakage, proline content, free amino acid and in PEP carboxylase activity. Content and yield of essential oil also significantly decreased in plants that faced water stress. Thus, it was concluded that variety Neema is the more tolerant variety as compared to Krishna on the basis of content and oil yield and well adapted to drought stress conditions.     

Developmental- and stress-mediated expression analysis of cinnamoyl-CoA reductase 1 (CCR1) from Hibiscus cannabinus

Cinnamoyl-CoA reductase (CCR, EC 1.2.1.44) is an important enzyme responsible for lignin biosynthesis in plants that belongs to the family of oxidoreductases. We analyzed developmental, tissue specific, and stress-mediated expression of the HcCCR1 (HM151381) gene from Hibiscus cannabinus. Gene expression analysis revealed that HcCCR1 was highly upregulated in mature leaves of 16-week-old plants. The maximum downregulation and upregulation of HcCCR1 was caused by cold and MeJA treatment, respectively. Sequence analysis demonstrated that HcCCR1 protein (ADK24219) contains a conserved NWYCYGK catalytic domain, while bioinformatics prediction indicated the presence of a palmitoylation site in the HcCCR1 protein. Phylogenetic analysis showed that HcCCR1 is more closely related to HcCCR2 (AGJ84130) and AtCCR proteins than CCR-like proteins. Comparative sequence analysis showed presence of significant differences between HcCCR1 and HcCCR2, which are homologs of H. cannabinus. Expression analysis demonstrated that the HcCCR1 gene is modulated by different external stresses.     

Gene expression and activity of antioxidant enzymes in barley (Hordeum vulgare L.) under controlled severe drought

The objective of the present study was to determine the activity of antioxidant enzymes: superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) and the expression of their genes in two barley genotypes under controlled severe drought. To fulfill this objective, 21-day-old barley plants of two genotypes: Rum and Yarmouk were exposed to controlled severe drought (25% field capacity) for 2, 9, and 16 days. The activity of SOD was significantly high in Rum genotype after 2 days of drought treatment. In Yarmouk genotype, the activity of APX was significantly high after 2 and 9 days of drought treatment. In Rum genotype, CAT2 was upregulated after 9 days of drought treatment and SOD and APX were upregulated after 16 days of drought treatment, whereas CAT2, SOD, and APX were upregulated in Yarmouk genotype after 2 days of drought treatment. The results indicate a unique pattern of activity and gene expression of the antioxidant enzymes in the two barley genotypes under controlled severe drought. Moreover, the data suggest that each genotype utilizes different molecular and biochemical responses under the same drought conditions.     

Photosynthetic adaptation of Euphorbia fractiflexa (Euphorbiaceae) and survival in arid regions of the Arabian Peninsula

Arid regions of the Arabian Peninsula are characterized by a short wet season with erratic rainfall, high temperature, and high evaporation. In these arid regions, the leafless stem succulent Euphorbia fractiflexa S. Carter & J.R.I.Wood (Euphorbiaceae) is an abundant perennial. Work presented in this paper aimed at investigating crassulacean acid metabolism (CAM) as a physiological adaptation crucial for survival of E. fractiflexa in arid regions of the Arabian Peninsula. Work involved investigations of stomatal diffusive conductance, chlorophyll fluorescence, and cell sap titratable acidity. Results represent the first report of obligate CAM in E. fractiflexa. Low values of stomatal conductance and dampening of CAM acidification–deacidification cycles during the long dry season also denoted tendency of this species to shift from obligate CAM to CAM-idling. Results also showed water stress-induced reduction in Photosystem II (PSII) activity occurring in concomitance with increased non-photochemical quenching of chlorophyll fluorescence denoting operation of non-photochemical energy dissipation mechanisms that are important for photoprotection of the photosynthetic machinery under stress conditions.     

Effects of supplementing two levels of magnesium aspartate and transportation stress on pork quality and gene expression of 𝛍-calpain and calpastatin of finishing pigs

The objective of this study was to investigate the effects of supplementing swine finishing diets with two levels of magnesium aspartate (MgAsp) and short-term transportation stress on blood parameters, pork quality and the mRNA abundance of μ-calpain and calpastatin in muscles of finishing pigs. Thirty-six crossbred finishing pigs (mean BW 90 kg) were assigned randomly to 0, 1000, or 2000 mg supplemental Mg from MgAsp per kg of diet for five days before slaughter. Then six pigs from each dietary treatment were subjected either to no transportation stress (NTS) or 2 h of transportation stress (TS). Transportation stress resulted in higher concentrations (p < 0.01) of serum calcium, glucose and cortisol, lower pH (p < 0.01), higher Warner-Bratzler shear force (WBSF) (p < 0.05) and higher calpastatin mRNA abundance (p = 0.05) of longissimus muscle (LM) compared with NTS treatments. Supplementation of MgAsp in TS treatments increased serum Mg concentration (p < 0.05) at 2000 mg of Mg/kg, reduced drip loss (p < 0.05) and improved pork quality colour (p < 0.05) at 2000 mg of Mg/kg, and decreased 1-day and 3-day WBSF (p < 0.05) at 1000 mg of Mg/kg compared with TS treatments fed the control diet. It is concluded that supplementation of MgAsp improves water-holding capacity and pork colour, and alleviates the negative effects of transportation stress on meat tenderness.     

Effect of Ligustrum lucidum and Schisandra chinensis on the egg production,antioxidant status and immunity of laying hens during heat stress

Abstract

The experiment was conducted to evaluate the effect of two plants belonging to Chinese herbal medicines, Ligustrum lucidum (LL) and Schisandra chinensis (SC), on the laying performance, antioxidant status and immunity of hens during heat stress. The results showed that diets supplement with 1% of either LL or SC had beneficial effects on egg production and FCR of hens during heat stress (p < 0.05), compared with the control group. Either LL or SC significantly reduced malondialdehyde (MDA) concentration of heart, liver, sera and egg yolk. In addition, glutathione reductase (GR) activity of tissues and sera of the birds was significantly elevated by supplementation LL or SC. Furthermore, LL or SC supplementation significantly elevated lymphoblastogenese of the birds and the antibody values against Newcastle disease virus (NDV). The results suggest that diets supplement with 1% of either LL or SC may enhance egg production, immune function, and antioxidant status of hens during heat stress.     

Optimal barn characteristics for high-yielding Holstein cows as derived by a new heat-stress model

Meticulous planning is required to minimize heat-stress conditions in barns. The objective of this study was to determine optimum barn characteristics for high-yielding dairy cows under Israeli (Mediterranean) summer ambient conditions, by using a new stress model that takes ambient temperature, relative humidity and wind velocity into account. During the summers of 2004 and 2005, three meteorological stations were alternately installed in 39 barns: two stations inside the barn at the prevailing downwind direction, and a third station outside the upwind end of the barn. Ambient temperature, relative humidity, wind speed and direction were measured and recorded every 10 min for 3 to 5 consecutive days at each barn in turn. The data were collected at different geographical and climatic conditions. Therefore, the data collected by an outside station were used as covariates. A heat-stress model was used to determine the threshold temperature (THRT) at which a cow begins to increase its respiratory rate; THRT was the response variable in the statistical model. The THRT model takes in account assumed values of a cow's physiological characteristics: daily milk yield of 45 kg, containing 3.5% fat, and 3 mm fur depth. The independent variables were: orientation, barn type, roof slope, roof ridge, marginal height, roof type (fixed or sliding) and barn width. Results showed that the optimal barn for high-yielding cows is the loose-housing type, oriented with its long axis perpendicular to the prevailing wind direction. Advantageous to the design would be an open ridge or pagoda with marginal height of over 4.7 m for north-south orientation and over 5 m for east-west orientation, roof slope over 11%, and barn width between 43 and 51 m for north-south orientation but lower than 42 m for east-west orientation. A sliding roof was also found to be an excellent solution when outside yards are banned by environmental regulations.     

Studies on the paradox of seedling rarity in Vaccinium myrtillus L. in NE Scotland

Summary

On the moors studied Vaccinium myrtillus produced many berries containing highly viable seed, yet seedlings were rare. Offtake of berries by birds or mammalian herbivores was apparently minor, most berries simply falling from the bushes when ripe. Fallen berries quickly disappeared, probably being removed by small rodents. Berries were fed experimentally to captive field voles and capercaillies, and it was found that only c. 1% of the seeds survived. For the voles, most of these viable seeds probably resulted from contamination of the droppings with partially-eaten berries or discarded extracted seeds, processes which must contribute to dispersal in the wild. The soil seed-bank was shown to be small, and the viability of buried seed declined from c. 90% to c. 20% in 3 years, due to decay in the soil H horizon and premature germination in the litter layer. Fewer seedlings established from experimental sowings on grass and Vaccinium myrtillus turf than on bare peat. We conclude that Vaccinium myrtillus has a seed-dispersal strategy which secures some long-distance movement by frugivores at the expense of much lost seed, and that the small seed-bank and low numbers of seedlings result from poor defence of the seeds and weak competitive ability of the seedlings; other attributes of Vaccinium myrtillus, e.g. efficient vegetative reproduction, compensate for these losses and enable it to be a successful species.     

手术室术前访视应用ipad对访视效果影响的研究

目的：探讨术前访视应用ipad在术前访视中对手术患者心理状态的影响。方法：将300例择期手术患者随机分为对照组（150例）和实验组（150例）,对照组采用常规术前访视方案;实验组在此基础上结合ipad展示围术期相关信息,采用焦虑自量表评估两组病人入院时和入手术室时的焦虑状况及血压、心率等指标,并且进行术后并发症和满意度的调查。结果：改良术前访视后焦虑评分、收缩压、舒张压、心率实验组明显低于对照组。结论：术前访视应用ipad可明显减轻手术病人术前的焦虑。     

Abiotic stress-associated microRNAs in plants: discovery, expression analysis, and evolution

Abiotic stresses such as drought, cold, and high salinity are among the most adverse factors that affect plant growth and yield in the field. MicroRNAs are small RNA molecules that regulate gene expression in a sequence-specific manner and play an important role in plant stress response. Identifying abiotic stress-associated microRNAs and understanding their function will help develop new strategies for improvement of plant stress tolerance. Here we highlight recent advances in our understanding of abiotic stress-associated miRNAs in various plants, with focus on their discovery, expression analysis, and evolution.