Micro-morphometry of cereal and non-cereal pollen using LM, CLSM and FESEM: Implications for past anthropogenic activities in the Central Ganga Plain India

One of the most important criteria to distinguish wild grasses from those of cultivated ones lies in their pollen micro-morphological characteristics, which has proven to be an immensely useful tool in reconstruction of the past human influence and paleoecology. The investigation of 22 species of cereal and non-cereal pollen using Light Microscopy (LM), Confocal Laser Scanning Microscopy (CLSM), and Field Emission Electron Microscopy (FESEM) is a maiden attempt from India to develop a biometric threshold for distinguishing cereal and non-cereal pollen. When we realize pollen studies to solve the query related to anthropization or inception of agricultural activities, it is important to clearly distinguish pollen grains of wild from cultivated grasses from Central Ganga Plain, which is regarded as the food basket of the country. The 8 species of cereal and 14 species of non-cereal pollen possess significant differences in Grain Diameter (GD) and Annulus Diameter (AD). The paired threshold (46–9 μm) appeared to be a discriminant pair, where cereal pollen bears the pollen grain and annulus diameter of above the threshold (>46, >9 μm) and non-cereal possess less than (<46, <9 μm). The pollen surface ornamentation of Poaceae pollen grains was also investigated extensively using FESEM for developing new tools to reconstruct past human habitation and climate. The various multivariate statistical analyses on the pollen micro-morphological characters, indicates the major clusters between the cereal and non-cereal pollen along with independent taxa, Zea mays . This extensive pollen morphological examination would provide a comprehensive dataset for the identification of fossil cereal and non-cereal pollen (upto the species level) in Ganga Plain and its comparison with other species growing around the country and neighboring regions.