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

Abstract

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 fivenerved 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.

Scanning electron microscopic imaging of palynological metaphors: A case study of family Poaceae taxa

“…Shaheen, Khan, Meo, and Akhtar (2005) stressed the taxonomic value of grass palynological characters by studying pollen morphology of three genera of Paniceae tribe and variations in pollen size as well in P / E ratio had been recorded. The current research of Shaheen et al (2021) reported that Echinochloa colona and Echinochloa crus‐galli can be differentiated on their pollen sizes.…”

“…Paniceae tribe and variations in pollen size as well in P/E ratio had been recorded. The current research ofShaheen et al (2021) reported that Echinochloa colona and Echinochloa crus-galli can be differentiated on their pollen sizes.However, palynological data of multiple Poaceae taxa had been explored in past but still gaps found in the literature. Many of the species have been neglected and their palynological data is missing.Moreover most of these studies reported the data observed underonly light microscopy.…”