أفكار أرنولد توينبي عن الحضارة الإسلامية ومدى تأثره برؤية ابن خلدون: دراسة وصفية و تحليلية

Ibn e Khaldun (1406 C.E.) has been an imminent scholar and well known for his work in the study of civilization. His vision regarding Civilization holds the significant place according to the philosophers of history. Arnold J. Toynbee (1975 C.E.) is one such prominent thinker who not only applauded the thoughts of Ibn e Khaldun but was influenced by Ibn e Khaldun’s views as it can be seen in Toynbee’s book: “A Study of History”. As a philosopher of history, he has much contribution in the field; He interlinks History with civilization. He presented a thoughtful book surrounding his civilizational vision; which explains the causes of world’s ups and downs. Although he presented a quality research about the division of the civilizations in the light of religion, many aspects of his work need to be reassessed. As per his understanding of world civilizations, he represents twenty-one civilizations, but with the passage of time, the number reduces and now only five are left in the contemporary epoch. According to him, religion has played significant role in the rise and fall of civilizations through their various stages. This research will highlight his thought about Islam through a comparison between Toynbee and Ibn e Khaldun’s Islamic civilizational thoughts. The study will also mention several problems in his approach to the Islamic Civilization. Furthermore, along with due importance of both scholars in the subject of history, their authoritative status will be stated. This research aims to discuss some misconceptions of the West that are based on Toynbee's understating of Islamic civilization and history. And, consequently, it intends to improve relations between people of the west and east.

Association of Metabolite Accumulation With Seasonal Variations in Evening Primrose Oenothera Biensis

Medicinal plants are important due to their antioxidant, antimicrobial properties. Of these evening primrose (Oenothera biensis L.) is used in the treatment of a number of diseases due to its distinct antioxidative and medicinal properties. The studies pertaining to seasonal patterns of growth behavior, survival strategies and secondary metabolites accumulation in leaves of different ages are not reported thus far. In this research, evening primrose was investigated for changes in the levels of secondary products, osmoprotectants, oxidants and antioxidants, vitamins, photosynthetic pigments and nutritional characteristics in penultimate, middle and bottom leaves on monthly intervals. Results revealed that plant showed better growth in spring (Feb-Apr) and autumn (Aug‒Oct) season, while summer (May‒Jul) and winter (Nov‒Jan) conditions were entirely damaging to growth. The osmoprotectants were highest in summer season followed by winter season, while in spring and autumn seasons the osmoprotectants remained low. These changes were sharper in penultimate followed by middle leaves while bottom leaves did not accumulate these compounds in sufficient quantities. The change in season had a great impact on the generation of hydrogen peroxide and malondialdehyde, which were the highest in summer season followed by winter and spring seasons. The activities of three enzymatic antioxidants were highest in summer season, while in winter season they were markedly lesser than summer but were normal in spring and autumn seasons. However, their accumulation was greater in penultimate and middle leaves than bottom leaves. Levels of vitamins including niacin, riboflavin and ascorbic acid in leaves were highest in summer season while inter season plants showed their significantly lesser levels. Penultimate leaf exhibited the sharper changes in their levels than other leaves. The accumulation of alkaloids, saponins, tannins, phenolics and flavonoids increased substantially in the summer season than other seasons. The anthocyanins, however, were low in summer but higher in in spring and autumn season. Chlorophylls were highest in spring season but decreased steadily towards summer season. Carotenoids synthesis was the highest in summer but the lowest in the spring season. Results regarding nutritional characteristics showed that K content decreased in winter season but was higher in summer season. The NO 3- -N, PO 43- -P, SO 42- -S and cellulose contents increased from spring to summer seasons but declined in autumn and winter seasons. Leaf starch content declined during summer season but was the highest in spring and autumn seasons. NDF, ADF and ADL increased in summer season but were quite low in winter season and showed moderate quantities in spring and autumn seasons. Soluble proteins were higher in summer and winter but low in spring and autumn. Changes in all these parameters were more conspicuous seen in penultimate and middle than aged bottom leaf. The correlations established amongst the monthly meteorological data and changes in the values of all the physiological attributes revealed that seasonal changes were the key drivers in modulating the growth and physiological responses of evening primrose. These changes switch the plant metabolic phenomena in a way that plant survival is ensured under harsher conditions.