Cold Stress on Some Selected Boro Rice Seedlings and Amelioration by Biochemical Approaches

2026-06-17T07:05:55Z

Cold Stress on Some Selected Boro Rice Seedlings and Amelioration by Biochemical Approaches Ali, Md. Jafar Cold stress is one of the critical environmental conditions that adversely affects crop growth and development resulting limit of yield and productivity. Field and Laboratory experiments were carried out three successive years to investigate the morpho-physiological functions of seedlings of eight rice varieties for cold survival mechanism during low temperature in Northwest Bangladesh and yield potential. The test rice cultivars from BRRI hybrid- BRRI hybrid dhan3 and BRRI hybrid dhan5, and HYV rice were BR 18 (Shahjalal), BRRI dhan28, BRRI dhan29 while indigenous cultivars were Lafaya, Biron dhan and Jagli. The root and shoot length, root and shoot weight, mean germination time, % survival or mortality, seedling vigor were recorded. Antioxidant enzyme activities like superoxide dismutase (SOD) and peroxidase (POD) were investigated at low temperature during study period. The leaf proline, chlorophyll, total carotenoid content was determined at ambient cold temperature and 6 °C in growth chamber during study period. Results indicated that low temperature and rice varieties had significant effect on the parameters studied while the salicylic acid positively improved the seedling growth and vigor. The superoxide dismutase (SOD) and peroxidase (POD) activities were increased in BRRI hybrid dhan5 at cold environment than those of other tested varieties. The BRRI hybrid dhan5 synthesized the highest amount of proline at 6 °C but the lower at ambient low temperature. The lowest amount of proline among the tested varieties was observed in cv. Lafaya at ambient low temperature and at 6 °C Similarly, the highest amount of chlorophyll-a was biosynthesized by BRRI hybrid dhan5 at ambient temperature but 6 °C while Salicylic acid application stimulated the chlorophyll. A significant variability was observed among the varieties regarding survival rate and mortality. The survival potentiality at low temperature environment during study period was observed as BRRI hybrid dhan5>BRRI hybrid dhan3>BRRI dhan28>Lafaya>Biron, respectively. The present finding infers that BRRI hybrid dhan5 showed the better survival potentiality than those of indigenous varieties during cold temperature by increasing anti-oxidant enzyme activities, higher synthesizing proline, and chlorophyll production resulted more biomass partitioning in root and shoot and increased seedling vigor index with low mortality that might inhibit cold injury due to occasional cold wave during Boro seedling raising time in winter and protect the seedling from adverse climate change effect. Salicylic acid application of 75 ppm, a biochemical approach that positively increased the seedling survival and improved the seedling growth during cold stress might be helpful for seedling raising in Northwest Bangladesh. Cold Stress on Some Selected Boro Rice Seedlings and Amelioration by Biochemical Approaches; A Dissertation Submitted in accordance with the requirements of the Hajee Mohammed Danesh Science and Technology University, Dinajpur for the degree of DOCTOR OF PHILOSOPHY By Md. Jafar Ali, Student No. : 1105100, Session: January 2018; DEPARTMENT OF AGRICULTURAL CHEMISTRY, HAJEE MOHAMMED DANESH SCIENCE AND TECHNOLOGY UNIVERSITY DINAJPUR, BANGLADESH; December, 2022.

ISOLATION OF ANTIDIABETIC AND OTHER BIOACTIVE COMPONENTS FROM SOME MEDICINAL PLANTS AVAILABLE IN NORTHERN PART OF BANGLADESH

2022-04-18T08:21:46Z

ISOLATION OF ANTIDIABETIC AND OTHER BIOACTIVE COMPONENTS FROM SOME MEDICINAL PLANTS AVAILABLE IN NORTHERN PART OF BANGLADESH Sarkar, Pankaj Kumar Aqueous, chloroform and 80% ethanol extracts of both Clerodindrum infortuntum (CI) leaves and Tinospora cordifolia (TC) stems were prepared by usual method and their antidiabetic effect were studied in the type 2 diabetic model rats. Male Long—Evans rats bred at BIRDEM animal house were used in the study. Type 2 diabetes was induced by a single intraperitoneal injection of streptozotocin to 48 hours old pups and three months later after confirming with an IPGTT, type 2 rats were selected for experiment. The rats were divided into seven groups. Glibenclamide (5 mg/kg body weight) and extracts (1.25 g/kg body weight) were administered orally for 28 consecutive days with single feeding. The body weights of the rats were measured weekly. Serum glucose (glucose-oxidase), serum lipids and serum creatinine were measured by the enzymatic colorimetric method. At the beginning, the fasting serum glucose level (8.77-11.67 mmol/l) raised in all the STZ induced type 2 rats. There was no significant difference in blood glucose level among the groups (p=ns). Ethanol extract of C infortunatum leaves (ETCI) when compared to control showed a significant antidiabetic effect on the 29" day(Fasting blood glucose, mmol/L, M+SD,9.25+1.41 in control group vs 6.37+40.93 in ETCI treated group p<0.009). As expected glibenclamide also significantly (p<0.023) reduced the blood glucose level on the 29" day. The aqueous extract of C infortunatum leaves (AqCI), aqueous extract of T cordifolia stem (AqTC), ethanol extract of T cordifolia stem (ETTC) and chloroform extract of T cordifolia stem (CHTC) also reduced blood glucose levels by 18.16, 23.24, 4.41 and 14.9%, respectively but the reduction was not significant. Except CHTC all the groups showed significant antidiabetiic effect on the final day (p<0.04-0.001). Atherogenic lipids (cholesterol, triglycerides and LDL cholesterol) were found to decline by glibenclamide and 80% ETCI but the decrease was not statistically significant. HDL cholesterol was found to rise by 80% ETCI, but no significant change was found in the serum creatinine level in any group on the last day. The body weights of the rats in all the groups increased compared to their initial weights. In the second part of the study, chemical analyses of C infortunatum and T cordifolia were done. The study revealed that the ethanol extract of CI exerts had better hypoglycemic effect in comparison to TC extract in type-2 diabetic model rats. This effect was at least partly mediated by pancreatic action of CI. Chemical investigation of ETCI showed five different compounds at different Rr values, which were purified by column chromatography, preparative TLC and finally by HPLC. Very interestingly, the fraction-1 of Clerodendrum infortunatum (ETCI) showed significant insulin tropic effect compared to other fractions. Structural study of the fraction 1 by spectroscopic studies (like 1 H-NMR, '3 C-NMR, and Mass Spectroscopy study) indicated that it was the chlorophillic compound Phaeophytin. Diabetes mellitus, a complex metabolic disorder is an increasing concern, worldwide in terms of health. The disorder affects more than 100 million people worldwide and by 2030 it is predicted to affect 366 million. Type 2 diabetes, the commonest form of the disease globally, has now reached epidemic proportions in most parts of the world; rapidly developing countries are the forefront of this epidemic (WHO, 2006). This explosive increase in the prevalence of diabetes and the consequences of its complications and associated disorders represent the greatest health care challenge the world facing today.

Ph.D. Thesis

Cold Stress on Some Selected Boro Rice Seedlings and Amelioration by Biochemical Approaches

ISOLATION OF ANTIDIABETIC AND OTHER BIOACTIVE COMPONENTS FROM SOME MEDICINAL PLANTS AVAILABLE IN NORTHERN PART OF BANGLADESH