Experimental Study on Seismic Response Characteristics of Soil On Building Models Using 1-D Shake-Table.docx

ABSTRACT. This research investigates the impact of seismic response on the scaled 1:10 multi storey steel frame-model supported by isolated shallow footings placed on sand sample. One dimensional shake-table testing was carried out on four, three and two storeys steel Frame Model subjected to El-Centro 0.46pga Earthquake. Dynamic properties acceleration, displacement, natural frequency of the frame models on isolated footing with changing of storey height were measured. Moreover, it was found that acceleration responses and natural frequencies decreased with an increase in frame model height while displacement responses increased for a given foundation type with increased height. In conclusion, soil, the structure's height, and the materials properties all affect a structures seismic response during an earthquake

Sugarcane Production under Changing Climate: Effects of Environmental Vulnerabilities on Sugarcane Diseases, Insects and Weeds

Sugarcane is an important crop for bioenergy and sugar, contributing to Gross Domestic Product (GDP) of Pakistan. Global warming and increasing greenhouse gas emission result in the increased intensity and frequency of extreme weather events. Temperature stress is a major environmental stress that limits the sugarcane growth, productivity and metabolism worldwide. Numerous biochemical reactions are involved in plant development, and these biochemical reactions are very sensitive to temperature stress. Now a day, temperature stress is a major concern for sugarcane production and approaches for high yield of sugarcane under temperature stress are important agriculture goals. Sugarcane plant adapts a number of acclimation and avoidance mechanism against different environmental stress. Plant survival under different stresses depends on ability to generate and transmit the signal and biochemical and physiological changes. In future, climate change is an important consequence for sugarcane production in the world because of its relative low adaptive capacity, poor forecasting system and high vulnerable to natural hazard. In this review we briefly describe climate change effects on sugarcane, sugar production in several countries especially in Pakistan, future challenges for sugar production under changing climatic scenario and propose strategies for mitigation negative impacts of climate change

Drought stress in plants: An overview on implications, tolerance mechanisms and agronomic mitigation strategies

Drought is considered as one of the major limiting factors affecting growth and productivity of crop plants. It severely affects the morphological and physiological activities of the plants and hampers the seed germination, root proliferation, biomass accumulation and final yield of field crops. Drought stress disrupts the biosynthesis of chlorophyll contents, carotene and decreases photosynthesis in plants. It gradually reduces CO2 assimilation rates owing to decrease in stomatal conductance. In addition, drought affects cell membrane stability and disrupts water relations of a plant by reducing water use efficiency. To cope with these situations, plants adopt different mechanisms such as drought tolerance, avoidance and escape. In this review, we discussed about the effects of drought on morphological and physiological characteristics of plants and suggested the different agronomic practices to overcome the deleterious effects of drought stress

Water stress memory in wheat/maize intercropping regulated photosynthetic and antioxidative responses under rainfed conditions

Abstract Drought is a most prevalent environmental stress affecting the productivity of rainfed wheat and maize in the semiarid Loess Plateau of China. Sustainable agricultural practices such as intercropping are important for enhancing crop performance in terms of better physiological and biochemical characteristics under drought conditions. Enzymatic and non-enzymatic antioxidant enzyme activities are associated with improved abiotic tolerance in crop plants, however, its molecular mechanism remains obscure. A 2-year field study was conducted to evaluate the influence of intercropping treatment viz. wheat mono-crop (WMC), maize mono-crop (MMC), intercropping maize (IM) and wheat (IW) crops, and nitrogen (N) application rates viz. control and full-dose of N (basal application at 150 and 235 kg ha−1 for wheat and maize, respectively) on chlorophyll fluorescence, gas exchange traits, lipid peroxidation, antioxidative properties and expression patterns of six tolerance genes in both crops under rainfed conditions. As compared with their respective monocropping treatments, IW and IM increased the Fo/Fm by 18.35 and 14.33%, PS-11 efficiency by 7.90 and 13.44%, photosynthesis by 14.31 and 23.97%, C-capacity by 32.05 and 12.92%, and stomatal conductance by 41.40 and 89.95% under without- and with-N application, respectively. The reductions in instantaneous- and intrinsic-water use efficiency and MDA content in the range of 8.76–26.30% were recorded for IW and IM treatments compared with WMC and MMC, respectively. Compared with the WMC and MMC, IW and IM also triggered better antioxidant activities under both N rates. Moreover, we also noted that intercropping and N addition regulated the transcript levels of six genes encoding non-enzymatic antioxidants cycle enzymes. The better performance of intercropping treatments i.e., IW and IM were also associated with improved osmolytes accumulation under rainfed conditions. As compared with control, N addition significantly improved the chlorophyll fluorescence, gas exchange traits, lipid peroxidation, and antioxidant enzyme activities under all intercropping treatments. Our results increase our understanding of the physiological, biochemical, and molecular mechanisms of intercropping-induced water stress tolerance in wheat and maize crops

Seed Priming with Sorghum Water Extract Improves the Performance of Camelina (Camelina sativa (L.) Crantz.) under Salt Stress

Seed priming with sorghum water extract (SWE) enhances crop tolerance to salinity stress; however, the application of SWE under salinity for camelina crop has not been documented so far. This study evaluated the potential role of seed priming with SWE in improving salt stress tolerance in camelina. Primed (with 5% SWE and distilled water-hydropriming) and nonprimed seeds were sown under control (no salt) and salt stress (10 dS m−1) conditions. Salinity reduced camelina’s emergence and growth, while seed priming with SWE improved growth under control and stress conditions. Under salt stress, seed priming with SWE enhanced emergence percentage (96.98%), increased root length (82%), shoot length (32%), root dry weight (75%), shoot dry weight (33%), α-amylase activity (66.43%), chlorophyll content (60–92%), antioxidant enzymes activity (38–171%) and shoot K+ ion (60%) compared with nontreated plants. Similarly, under stress conditions, hydrogen peroxide, malondialdehyde (MDA) content, and shoot Na+ ion were reduced by 60, 31, and 40% by seed priming with SWE, respectively, over the nonprimed seeds. Therefore, seed priming with SWE may be used to enhance the tolerance against salt stress in camelina