Light and scanning electron microscopic comparative studies of geminivirus infected and healthy Eclipta alba (L.).

Eclipta alba (L.) is a valuable medicinal plant. However, its medicinal efficacy can be affected by geminivirus infection. Therefore, identification of healthy specimen is essential before to use as medicine. The present study provided the taxonomic characterization of geminivirus infected and healthy E. alba plant by studying apparent morphology and microscopic features through light and scanning electron microscopy. Before taxonomic characterization infected and healthy specimens were separated through molecular detection of geminivirus. Results of morphological studies reported that geminivirus infected E. alba plant showed systematic symptoms of infection like stunted growth, distortion and chlorosis of leaves, decrease in size of root, shoot and fruit, and so forth in comparison to healthy specimen. Anatomical findings reported that in both plants anomocytic and anisocytic types of stomata with multicellular warty trichomes were present. However, variations were observed in quantitative measures such as size of trichomes, epidermal, subsidiary and guard cells. Palynological observations identifies that both plants possessed tricolporate type of pollen but variation was mainly observed in size and shape of pollen, thickness of exine and intine, P/E ratio, pore size, interspecific difference, size of colpi, and pollen ornamentation. Overall this study concluded that both healthy and infected E. alba do not reported much variations in qualitative taxonomic features, but can be differentiated in terms of quantitative taxonomic evidences. Future studies are recommended for pharmacological analysis of both healthy and virus infected plants. RESEARCH HIGHLIGHTS: Eclipta alba has incredible therapeutic worth, but due to geminivirus infection the plant is affecting badly. Hence, the present studies give a comprehensive taxonomic report on the geminivirus infected and healthy plant species.

Morphological and palynological assessment of some taxa of genus Echinochloa through light and scanning electron microscopy.

The present study was undertaken to gather information on selected species of Echinochloa based on their morphological and palyonological examination through light and scanning electron microscopy. As the Echinochloa species are most problematic grass weeds and exhibit high interspecific and intraspecific variability so due to their great morphological diversity it is difficult to recognize them. A lot of variation was observed in morphological features of studied taxa. In the present study, E. colona had more or less spreading dense racemes whereas in E. crus-galli racemes were linear to ovate. Upper glume surface was pubescent in E. colona, hispid in E. crus-galli and spinose in E. walteri. E. colona was comprised of five-nerved glumes whereas in E. crus-galli glumes were three-nerved. Although pollen basic characters in family Poaceae remains consistent but great variation was observed in pollen of studied taxa. The pollen size was quite variable among the species of genus Echinochloa. In polar view, the size of pollen grains ranged from 27.5 (20-35) µm to 40 (30-50) µm. E. crus-galli was appeared to be the smallest in size whereas E. colona was the largest.). P/E ratio ranged from 0.84 to 1.15 µm among the species. The highest value of pollen fertility was found in E. colona as 93.33% and lowest was in E. crus-galli as 87.50%. The morphological key of studied taxa is also given to study variations. In conclusion, it was observed that microscopy of morphological and palynological assessment can play a vital role in identification of taxonomically problematic taxa.

Light and scanning electron microscopic study of genus Echinochloa species inhabited in Pakistan.

Grass taxonomy is quite problematic and insignificant taxonomic work has been done on Echinochloa with special reference to Pakistan. Therefore, the present study was carried out to provide taxonomic keys for the identification of this genus through microscopic epidermal leaf anatomical parameters. Light microscopy and scanning electron microscopy were done to delimit the different species. Special structures like hook cells, short and long cells, stomata, macro- and micro-hairs, prickles and silica bodies showed a lot of variation among each species. For instance, E. frumentacea can be distinguished from E. walteri by the presence of macro hairs between the veins. Furthermore, E. crus-galli can be distinguished from E. frumentacea in terms of macro hair size, that is, 45-60 µm and 20-60 µm, respectively. Similarly, E. colona showed marked variations in terms of prickles abundance from E. frumentacea. Overall results of this research reports valuable qualitative and quantitative diagnostic futures for the genus Echinochloa.