This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic), transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i) an increased level in xyloglucan endotransglucosylase/hydrolase (XTH) and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii) an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions.

/pdf/cell-wall-metabolism-in-response-to-abiotic-stress-rzxxqglg97.pdf

Cell Wall Metabolism in Response to Abiotic Stress.

Ethnographic Research: A Guide to General Conduct

The number and intensity of heat waves has increased, and this trend is likely to continue throughout the 21st century. Often, heat waves are accompanied by drought conditions. It is projected that the global land area experiencing heat waves will double by 2020, and quadruple by 2040. Extreme heat events can impact a wide variety of tree functions. At the leaf level, photosynthesis is reduced, photooxidative stress increases, leaves abscise and the growth rate of remaining leaves decreases. In some species, stomatal conductance increases at high temperatures, which may be a mechanism for leaf cooling. At the whole plant level, heat stress can decrease growth and shift biomass allocation. When drought stress accompanies heat waves, the negative effects of heat stress are exacerbated and can lead to tree mortality. However, some species exhibit remarkable tolerance to thermal stress. Responses include changes that minimize stress on photosynthesis and reductions in dark respiration. Although there have been few studies to date, there is evidence of within-species genetic variation in thermal tolerance, which could be important to exploit in production forestry systems. Understanding the mechanisms of differing tree responses to extreme temperature events may be critically important for understanding how tree species will be affected by climate change.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1111/pce.12417

Responses of tree species to heat waves and extreme heat events

Abstract Drought and heat stresses are important threat limitations to plant growth and sustainable agriculture worldwide. Our objective is to provide a review of plant responses and adaptations to drought and elevated temperature including roots, shoots, and final yield and management approaches for alleviating adverse effects of the stresses based mostly on recent literature. The sections of the paper deal with plant responses including root growth, transpiration, photosynthesis, water use efficiency, phenotypic flexibility, accumulation of compounds of low molecular mass (eg proline and gibberellins), and expression of some genes and proteins for increasing the tolerance to the abiotic stresses. Soil and crop management practices to alleviate negative effects of drought and heat stresses are also discussed. Investigations involving determination of plant assimilate partitioning, phenotypic plasticity, and identification of most stress-tolerant plant genotypes are essential for understanding the complexity of the responses and for future plant breeding. The adverse effects of drought and heat stress can be mitigated by soil management practices, crop establishment, and foliar application of growth regulators by maintaining an appropriate level of water in the leaves due to osmotic adjustment and stomatal performance.

/pdf/effect-of-drought-and-heat-stresses-on-plant-growth-and-54mhsg8qi3.pdf

Effect of drought and heat stresses on plant growth and yield: a review

Maize is a sensitive crop to drought and heat stresses, particularly at the reproductive stages of development. The present study investigated the individual and interactive effects of drought (50% field capacity) and heat (38 °C/30 °C) stresses on morpho-physiological growth, yield, nutrient uptake and oxidative metabolism in two maize hybrids i.e., ‘Xida 889’ and ‘Xida 319’. The stress treatments were applied at tasseling stage for 15 days. Drought, heat and drought + heat stress caused oxidative stress by the over-production of ROS (O2−, H2O2, OH−) and enhanced malondialdehyde contents, which led to reduced photosynthetic components, nutrients uptake and yield attributes. The concurrent occurrence of drought and heat was more severe for maize growth than the single stress. However, both stresses induced the metabolites accumulation and enzymatic and non-enzymatic antioxidants to prevent the oxidative damage. The performance of Xida 899 was more prominent than the Xida 319. The greater tolerance of Xida 889 to heat and drought stresses was attributed to strong antioxidant defense system, higher osmolyte accumulation, and maintenance of photosynthetic pigments and nutrient balance compared with Xida 319.

/pdf/interactive-effects-of-drought-and-heat-stresses-on-morpho-1710upuhtt.pdf

Interactive effects of drought and heat stresses on morpho-physiological attributes, yield, nutrient uptake and oxidative status in maize hybrids.

Eight spring wheat cultivars were evaluated under three heat stress conditions (early, late and very late) in order to identify suitable cultivars to develop heattolerant genotypes resistant to future global warming. Results from the study indicate that stress did not negatively affect flag leaf area in ‘Prodip’ and ‘Sufi’, flag leaf dry matter partitioning in ‘Prodip’, ‘BARI Gom-26’ and ‘Shatabdi’, above-ground dry matter partitioning in ‘Shatabdi’ and ‘BARI Gom-26’, seedling emergence in ‘Sufi’ and ‘BARI Gom-26’, or tiller production in ‘Sufi’ and ‘BARI Gom-26’. With respect to lower yield reduction, relative performance and heat susceptibility index (HSI), ‘Sufi’ was highly heat stress-tolerant, followed by ‘BARI Gom-26’ and ‘Shatabdi’. On the basis of HSI values in early heat stress and extremely late heat stress (corresponding to early and extremely late sowing), ‘BARI Gom-26’ (HSI=0.10, 0.65) and ‘Shatabdi’ (0.22, 0.62) were highly tolerant to early heat stress and moderately tolerant to extremely late heat stress while ‘Sufi’ was highly tolerant (0.35) to extremely late heat stress and moderately tolerant (0.51) to early heat stress. All other genotypes were susceptible to heat stress, among which ‘Gourab’ (2.19, 1.46) was the most susceptible followed by ‘Sourav’ (1.19, 1.42), ‘Prodip’ (1.03, 1.23), ‘BARI Gom-25’ (1.61, 0.89) and ‘Bijoy’ (1.04, 1.28). Thus, ‘BARI Gom-26’, ‘Shatabdi’ and ‘Sufi’ have the greatest potential to be used as high-yielding wheat genotypes under warm to hot environments and could be used in a breeding programme to develop heat-tolerant wheat.

https://ijpp.gau.ac.ir/article_1121_473a2481e1babb454f403aa4979faefd.pdf

Evaluation of growth, yield, relative performance and heat susceptibility of eight wheat (Triticum aestivum L.) genotypes grown under heat stress

Effect of nitrogen level on aromatic rice varieties and soil fertility status.

Nitrogen (N) in plants is generally diagnosed by a soil test and plant tissue analysis. However, such analyses are costly in terms of time and money and are not easily accessible by researchers and extension workers, let alone farmers. Alternative cost-effective methods are required for rapid analysis of the N status of crops and to guide N management in wheat. The objective of this study was to assess whether the SPAD values using a leaf chlorophyll meter could be used to apply N at the maximum tillering (MT) stage of irrigated spring wheat grown under light soils of South Asia. Experiments were conducted over two years under light soils at the Wheat Research Centre (WRC), Dinajpur, Bangladesh. Treatments were 80, 100 and 120 kg N ha −1 , applied two-thirds as basal and one-third at the crown root initiation (CRI) stage along with additional 10, 20 and 30 kg N ha −1 (first year) and 0, 10, 20 and 30 kg N ha -1 (second year) at MT. Rates at MT were determined on the basis of SPAD values, which fell below the critical value of 37.5, recorded at 45 days after sowing (DAS). SPAD values recorded at 55 and 65 DAS were positively correlated with grain yield (GY), indicating that the application of extra N at MT influences wheat GY. Our results have two major implications: (i) SPAD values based on a leaf chlorophyll meter can be used for N application and (ii) extra 30 kg N ha -1 at MT is

http://ijpp.gau.ac.ir/article_2898_e777a6d62b83717f87ee1c19509f9a1d.pdf

Chlorophyll meter – a decision-making tool for nitrogen application in wheat under light soils

In present situation, companies can gain strong competitive advantage through applying effective and efficient human resource practices. If the human resources are managed properly, they can contribute to the success for the company. The effective management of human resource is possible through the implementation of sound HRM practices. The main objective of this research is studying the impact of HRM practices on employee performance in the context of cement industry in Bangladesh. For this purpose the researchers have tried to investigate impact of the various components of HRM practices on employee performance of a sample of 160 employees from seven cement companies listed in the Dhaka Stock Exchange. The data were analyzed by a regression analysis to determine the impact of HRM practices on employee performance. The result shows that training & development and opportunity for career development have a significant positive impact on employee performances. On the other hand, Performance appraisal, Compensation & Benefits, and Leadership Practices have a positive impact on employee performance but the impact is not significant in the context of cement industry in Bangladesh. Moreover, work life balance has a negative impact on employee‘s performance. Furthermore, efficient management of human resources can increase the performance of the employees of the cement companies in Bangladesh.

https://papers.ssrn.com/sol3/Delivery.cfm/SSRN_ID2570704_code2360963.pdf?abstractid=2570704&mirid=1&type=2

HRM Practices and its Impact on Employee Performance: A Study of the Cement Industry in Bangladesh

The present study deals with an ethnobotanical investigation of the utilization of orchids as medicine by the ethnic communities (Chakma, Marma, Tanchangya, Rakhain and Bengali) of Cox’s Bazar and Chittagong Hill Tracts Districts of Bangladesh. The information has been documented by interviewing the traditional healers and various elderly people from five communities following different ethnobotanical methods. The documented information compiled a total of nine orchid species which have been used individually or in combination with different plant parts of other species to treat 42 diseases. The most frequent diseases found to treat in the current investigation are rheumatism, inflammation, fever, paralysis, earache and epilepsy. The species have been presented along with their scientific and local names, family, short description and their ethnomedicinal uses. The herbal medicines have been found to be prepared in various ways likejuice, decoction, paste, pill and sometimes the plant parts directly used as raw element. From the documented information it is revealed that the most frequently used part of orchid is leaf.

Mst. Momena Akhter

Papers

Evaluation of growth, yield, relative performance and heat susceptibility of eight wheat (Triticum aestivum L.) genotypes grown under heat stress

Effect of nitrogen level on aromatic rice varieties and soil fertility status.

Chlorophyll meter – a decision-making tool for nitrogen application in wheat under light soils

HRM Practices and its Impact on Employee Performance: A Study of the Cement Industry in Bangladesh

Ethnobotanical investigation of some orchids used by five communities of Cox’s Bazar and Chittagong hill tracts districts of Bangladesh