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[en] Shape changes in wheat grain under heat stress become necessary to determine when shrinkage causes quality loss. High throughput seed morpho-metery is required to quantify the shape changes precisely. In this study, shrinkage of the seed under heat stress has been quantified thus can be used as the indicator of heat stress. Randomized complete block design was followed in which 49 genotypes were examined in 16 replicates, under two treatments (normal and late sown). SmartGrain software was used to quantify the digital images of seeds picked up from two treatments for each genotype in 16 replicates. Seed shape descriptors (length, width, length width ratio, area, perimeter, circularity) were precisely and robustly determined by the use of this software. ANOVA results showed significant effect of heat stress on seed shape. Critical difference, chi-square value mentioned the disparity in seed shape of normal and stressed wheat crop. Maximum heat susceptibility index for seed area was noted (2.38) and the minimum remained (0.02). Principal component analysis (PCA) revealed the relative importance of seed shape attributes and genotype by explaining about 85.02 percent (F1 = 59.87 percent and F 2 = 25.16 percent) variability. (author)
[en] F1 progenies of 7x7 diallel fashion crosses comprising four high temperatures tolerant and three susceptible spring wheat parental genotypes were evaluated under normal and heat stress conditions. The characters days to heading, spike index at anthesis, plant height, spikes per plant, spikelets per spike and grain yield per plant were studied under both conditions. Analysis of variance under both conditions indicated additive gene action with partial dominance suggesting that these traits might be useful for the development of terminal heat tolerant varieties by modified pedigree selection.. However overdominance type of gene action was recorded for spikelets per spike suggesting that further improvement in this trait may be effected by biparental mating coupled with few cycles of recurrent selection. (author)
[en] Rubisco activase (RCA) that functions as a molecular chaperone regulates the activity of the Calvin-Benson cycle via regulation of the Rubisco activity. In plants such as Arabidopsis thaliana, Spinacia oleracea, and Oryza sativa, there are two RCA isoforms from two mRNAs that are produced from alternative splicing of the transcribed pre-mRNA of a single RCA gene. However, this research reported that the transcripts of the two IbRCA isoforms in sweet potato (Ipomoea batatas) were transcribed from two different genes. To study the roles of these two IbRCA isoforms in photosynthesis, we inserted these two IbRCA genes into the genome of Arabidopsis with deletion of RCA gene (RCA), resulting in IbRCAs- and IbRCAl-expressing plants, respectively. Analysis of these transgenic Arabidopsis indicated that the IbRCAs-expressing plants were similar to wild-type plants under ambient CO/sub 2/ concentration and 22 degree C conditions, suggesting that expression of IbRCAs gene was sufficient for functional complementation of RCA plants under normal conditions. However, IbRCAs-expressing plants were more susceptible to moderate heat stress (26 degree C) compared to wild-type plants. In contrast, although the IbRCAl-expressing plants had to grow normally in high CO/sub 2/ concentration conditions, there were almost no differences in growth and photosynthesis between normally grown and heat-treated plants, implying that IbRCAl-expressing plants had a better heat-resistance than IbRCAs-expressing plants. (author)
[en] Climate change is predicted to increase the intensity and negative impacts of urban heat events, prompting the need to develop preparedness and adaptation strategies that reduce societal vulnerability to extreme heat. Analysis of societal vulnerability to extreme heat events requires an interdisciplinary approach that includes information about weather and climate, the natural and built environment, social processes and characteristics, interactions with stakeholders, and an assessment of community vulnerability at a local level. In this letter, we explore the relationships between people and places, in the context of urban heat stress, and present a new research framework for a multi-faceted, top-down and bottom-up analysis of local-level vulnerability to extreme heat. This framework aims to better represent societal vulnerability through the integration of quantitative and qualitative data that go beyond aggregate demographic information. We discuss how different elements of the framework help to focus attention and resources on more targeted health interventions, heat hazard mitigation and climate adaptation strategies.
[en] Since HSP70 is the stress response protein, the impact of heat stress on semen quality may be displayed through the expression of protein profile and HSP70. This study investigated the seasonal effects on the protein profiles and HSP70 in spermatozoa and seminal plasma of 10 Holstein crossbred bulls from an AI centre located in Lopburi, Thailand. Bull semen was collected weekly for 8 consecutive weeks during rainy (average THI 79.34), cool (average THI 75.27), and summer (average THI 80.10) seasons. Protein was extracted from both spermatozoa and seminal plasma using Laemmli's sample buffer. The protein profiles of spermatozoa and seminal plasma were subjected to one-dimensional SDSPAGE with 12% (w/v) acrylamide gel and 4.0% (w/v) acrylamide stacking gel for 120 min. at 8 mA. To visualize the protein profiles, gels were fixed in acetic acid: ethanol: H2O (7: 40: 53), stained with 0.125% (w/v) Coomassie blue R-250 in acetic acid: ethanol: H2O (7: 40: 53) for 60 min., and distained with acetic acid: ethanol: H2O (11: 26: 63) until the background was clear. Western blotting, as described by Kamaruddin et al. was conducted to determine HSP70 using anti-HSP70 monoclonal antibody. Proteins in the polyacrylamide gel were electrophoretically transferred, for 90 min. at 156 mA, to a PVDF membrane. The membrane was rinsed in PBS and blocked overnight in a blocking solution (advanced ECL blocking; Amersham Life Science Inc., Oakville, ON, Canada). The membrane was then incubated for 1 h at room temperature with monoclonal anti-HSP70 (H5147 Sigma Chemical Supplies CO., LTD), incubated with anti-mouse IgG horse radish peroxidase conjugated for 1 h at room temperature, and then detection for immunoreactive bands using ECL detection reagents (Amersham Life Science Inc.) on scientific imaging film. It was found that the profiles of protein were not different among seasons in both sperm and seminal plasma. The profiles of spermatozoa protein range from 10 to 220 kDa while most of proteins found in seminal plasma were low molecular weight (14-30 kDa). The HSP70 was found in both sperm and seminal plasma. However, the amount of HSP70 in winter appears to be greater compare to those found in summer and rainy seasons