Variation in seed morphometric characters, oil content and azadirachtin content of seeds, in vitro shoot cultures and callus cultures among different populations of Azadirachta indica

We studied seed morphometric characters, oil content and azadirachtin content in a medicinally important and insect repellent tree species Azadirachta indica A.Juss. Ten populations were selected from two central Indian states of Madhya Pradesh and Chhattisgarh and twenty candidate plus trees were selected from each population based on tree attributes. Azadirachtin content was estimated in seeds, in vitro shoots and callus cultures through HPLC. Significant variation（p ／ 0.05） was observed in seed morphometric characters, oil content and azadirachtin content among the ten populations. Maximum value for 100 seed weight was obtained in seeds of Raigarh（30.51 g） which was on par with seeds of Bargi（28.37 g）and Chhatarpur（26.36 g）. The ratio of highest kernel to seed was also obtained in seeds of Raigarh（60.11%）.Kernels from Chhatarpur population recorded the highest oil content（24.20%）, which was equal to that in Sihore（23.75%） and Katni（21.75%）. We recorded highly significant variation in azadirachtin content in seed samples,in vitro shoot samples and callus cultures. Maximum azadirachtin was present in the seeds of Gwalior（0.882%）which was on par with azadirachtin content in seeds of Chhatarpur, Katni, Sihore, Shahdol and Chhindwara.Maximum azadirachtin in the in vitro shoots was present in the cultures of Gwalior（0.218%） which was statistically on par with Sihore（0.176%）. Similarly, in callus cultures of nodal segments maximum azadirachtin was recorded in the Gwalior population（0.033%） which was statistically on par with Sihore（0.028%）. The trees of Gwalior and Sihore populations can be produced in large numbers through vegetative propagation to obtain seeds with higher azadirachtin content.

Plastic occurrence,sources,and impacts in Antarctic environment and biota

Several studies have documented that plastic pollution is affecting one of the most remote and pristine regions of our planet,Antarctica.Plastics of different size and polymeric composition have been retrieved in Antarctic sea ice,surface waters and sediments,with microplastics(mostly fibers)found both in terrestrial and marine organisms.Such evidence raises concerns about potential detrimental effects on biodiversity and ecosystem functions.The present review aims to report the most up-to-date knowledge on occurrence and distribution of plastic pollution in the Antarctic environment and biota including interaction with microorganisms,potential sources,and its impact on Antarctic biota.Our understanding of plastic pollution in this polar region will help us define the human footprint in Antarctica and predict future ecological risks.