Light and scanning electron microscopic observation of palynological characteristics in spineless Astragalus L. (Fabaceae) and its taxonomic significance.

Palynological characterization is considered to be one of the significant taxonomic tools for the delimitation and identification of morphologically complicated taxa. Hence, the pollen morphology of 12 species of spineless Astragalus L. was examined using light and scanning electron microscopy. Studied pollen were small to medium, monad, prolate to per-prolate and tricolporate type in all studied taxa. The exine sculpturing varied from reticulate to microreticulate whereas colpus ornamentation ranged from scabrate to granulate. Furthermore, maximum polar and equatorial diameter was recorded in Astragalus leucocephalus Bunge. (45.00 µm) and A. pyrrhotrichus Boiss. (22.91 µm) while minimum in A. amherstianus Benth. ex Royle (28.75 µm) and A. amherstianus Benth. ex Royle (15.00 µm), respectively. Similarly, the ratio of polar to equatorial diameter was recorded maximum in A. ophiocarpus Boiss. (2.05). The width of colpi was larger in A. hamosus L. (1.29 µm) and smaller in A. ophiocarpus Boiss. (0.62 µm). We have also found the maximum value of mesocolpium in A. retamocarpus Boiss. (2.08 µm) while minimum in A. oxyglottis Steven ex M.Bieb. (1.87 µm). The quantitative pollen attributes helped in the development of pollen keys for the accurate and quick identification of the studied species. Furthermore, ordination and cluster analysis were performed for the differentiation of the investigated taxa at species level. Based on our results, we conclude that pollen features can be used for the delimitation and identification of the studied taxa. RESEARCH HIGHLIGHTS: Pollen micromorphology is a useful tool for classifying complicated taxa. The pollen micromorphology of 12 spineless species of Astragalus L. was studied using LM and SEM. The observed pollen characteristics aided in Astragalus L. serve for the identification and classification of taxa at specific level.

Identification of novel, non-edible oil seeds via scanning electron microscopy as potential feedstock for green synthesis of biodiesel.

In the present era, environmental glitches associated with extensive emission of greenhouse gases (GHG) and energy crises caused by exhausting fossil fuel reservoirs has diverted researcher's interest toward alternative and renewable energy sources. Biodiesel is a renewable, biodegradable, and sustainable alternative to petro-diesel. Biodiesel synthesized from non-edible seed oils is preferred due its cost effectiveness and eco-friendly nature. Hence, our present study focused on investigation and identification of micromorphological characters of six novel, non-edible seed oil feedstock for biodiesel production via scanning electron microscopy (SEM). Results of light microscopy of seeds revealed distinct variation in seed size (15.8-1.8 mm in length and 9.4-1.1 in width), shape (round to Cuneiform), and color (from black to yellowish green). Non-edible seed oil content fall in range of 28-38% (wt/wt). Free fatty acid (FFA) content varied from 0.56 to 2.06 mg KOH/g. Multivariate analysis was performed to investigate correlation between three significant variables of seed oil yielding feedstock such as potential for biodiesel synthesis, oil content, and FFA content via principal component analysis. Ultra morphological investigation of seeds surfaces via SEM exhibited distinctive variation in surface sculpturing, cell arrangement, cell shape, periclinal wall shape, margins, protuberances, and anticlinal wall shape. Seed surface sculpturing varied from reticulate, semitectate, wrinkled, rugose, papillate, perforate, and striate. Periclinal wall arrangements confirmed variation from glabrous, raised, depressed, elevated, smooth, pentagonal, entire, and ripple margins. Whereas, anticlinal walls pattern demonstrated variation from angular, smooth, wavy, deep, dentate, entire, irregular, puzzled, elongated, curved, and depressed. Finally, it was concluded from obtained results that SEM could be a possible useful tool in disclosing veiled micromorphological characters of non-edible oil yielding seeds, which provides useful information to researchers for their correct, authentic identification, and classification in modern synthetic system.

Microscopic implication and evaluation of herbaceous melliferous plants of southern Khyber Pakhtunkhwa-Pakistan using light and scanning electron microscope.

The aim of the present study is to investigate the pollen morphology of melliferous plant taxa of Southern Khyber Pakhtunkhwa-Pakistan. Using light microscope (LM) and scanning electron microscope (SEM), the palynological study of 18 species of melliferous plants namely Calendula arvensis, Cenchrus pennisetiformis, Citrullus colocynthis, Cucumis melo subsp. agrestis var. agrestis, Cucurbita maxima, Cymbopogon jwarancusa, Cynodon dectylon, Dactyloctenium aegyptium, Helianthus annus, Lagenaria siceraria, Launaea procumbens, Luffa cylindrica, Pennisetum glaucum, Saccharum spontaneum, Sonchus asper, Verbesina encelioides, Xanthium strumarium, and Zea mays was carried out. Both qualitative and quantitative characteristics of pollen were studied. Variations were observed in pollen morphology. The dominant pollen shape was prolate-spheroidal (11 species). All the pollen units were monad. The highest exine thickness was found in Citrullus colocynthis (8.45 µm). The maximum polar and equatorial diameter (102 and 97.55 µm) was found in Luffa cylindrica. Similarly, the highest P/E ratio was found in Cucurbita maxima (1.46). Most of the species showed tricolpate and monoporate type of pollen. The exine sculpturing, number of spines per pollen and between colpi and the pollen fertility and sterility provided significant results for the documentation of melliferous plants. Thus, the information listed in this article will prove helpful to identify the potential melliferous plants in the area, geographical origin of the honey, and the availability of pure honey in the local and international market.