STUDIES ON THE POLLEN MORPHOLOGY OF SOME WEEDY FLORA OF NIZAMABAD DISTRICT OF TELANGANA STATE, INDIA

 

Naveen Kumar Gaddala ¹, Chaya Pallati ²,  Chiranjeevi Midathapalli ³

 

¹ Assistant Professor of Botany, Government Degree College (Autonomous), Bodhan, Nizamabad, Telangana, India

² Assistant Professor, Department of Botany, Palynology and Paleobotany Research Laboratory, University College of Science, Saifabad, Osmania University, Hyderabad, Telangana, India

³ Research Scholar, Department of Botany, Palynology and Paleobotany Research Laboratory, University College of Science, Saifabad, Osmania University, Hyderabad, Telangana, India

 

1. INTRODUCTION

Weeds are the unwanted plants competing with crops and effect their yield.  They hamper the development of the crops and greatly diminish the harvest. Weeds are more effective at absorbing plant nutrients than crop plants and grow more vigorously in drought conditions. They decrease the efficiency of inputs, disrupt farming methods, lower crop quality, and also serve as hosts for various crop pests and diseases. Weeds thrive in arid areas due to their ability to withstand drought, quick growth from a vegetative stage to flowering, self-fertilization, and continuous seed production Murthy & Prathiba (1995). Some weeds also produce harmful substances that hinder crop growth. In traditional farming methods, weeds are manually pulled from fields using hands or tools like hoes. Another key approach to managing weed growth is intercropping between main crop rows. However, the increased use of chemical pesticides over the past fifty years, aimed at controlling weed growth among other issues, has led to numerous negative impacts on human health and the environment. The rise of herbicide-resistant weed populations is a significant concern in this context. For a successful weed management strategy that includes control, eradication, and prevention, it's crucial to accurately identify weeds based on their phenology, dispersal methods, distribution, and growth habits. Various characteristics are utilized in identifying plant taxa. Pollen characteristics are particularly useful for solving complex issues related to the interrelationships among different taxa and assessing their status within the classification, especially concerning their families, subfamilies, tribes, genera, species, and subspecies. A pollen study is an effective tool for identifying different species and taxa within their respective families. The unique characteristics of pollen are often described as a plant's "fingerprint." This method is applicable to all flowering plants. Each species has distinct pollen features, making pollen studies beneficial for taxonomic research and resolving issues related to the identity and authenticity of plant species. This study focuses on the pollen morphology of eight weed species collected from the Nizamabad district of Telangana State, with the goal of documenting pollen features that aid in the identification of these weed species.

 

2. Materials and Methods

Fresh flowers from eight different weed species were gathered during their flowering phase between the years 2022 and 2023 from the Nizamabad district in Telangana, India. The selected weed species include Mimosa pudica, Cleome viscosa, Tribulus terrestris, Lantana camara, Commelina benghalensis, Ziziphus mauritiana, Cardiospermum halicacabum, and Datura stramonium.

 

3. Methodology

To make the pollen slides from the polleniferous material (anthers) Erdman’s acetolysis method, 1960 was followed. The anthers from the collected weed plants were carefully transferred to a test tube containing 70% ethanol using forceps. The anthers were crushed using a glass rod and the suspension was filtered through a fine brass mesh. After centrifugation, the sediment was further processed by mixing it with 5ml of glacial acetic acid and then centrifuging again. Next, the resulting pollen sediment was treated with acetolysis solution, which is a combination of 9 parts acetic anhydride to 1 part Concentrated Suphuric acid. The slides prepared were then mounted in 50% glycerol. The slides containing the prepared pollen were examined under a light microscope (LM) to observe their morphological features. The characteristics of the pollen were analyzed using established reference literature, including works by Erdtman (1952), Erdtman (1960), Erdtman (1971), Erdtman (1978), Moore & Webb (1978), Punt et al. (2007), Usma et al. (2022), Jafari & Ghanbarian (2007), Pullaiah & Rao (1995), Sharma (1978), Tadulingam (1955), Gamble & Fischer (1915 - 1936), C.E.C. Fischer. Photomicrography of the pollen was performed using an Olympus trinocular microscope equipped with a Sony digital camera.

 

4. Results

Pollen characterization of eight types of weeds, namely Mimosa pudica, Cleome viscosa, Tribulus terrestris, Lantana camara, Commelina bhengalensis, Ziziphus mauritiana, Cardiospermum halicacabum, and Datura stramonium, which are referable to families such as Mimosaceae, Cleomaceae, Zygophyllaceae, Verbinaceae, Commelinaceae, Rhamnaceae, Sapindaceae, and Solanaceae, were conducted to observe the pollen features. The pollen grains displayed a range of morphological characters. The specific pollen features observed are given below.

S. No.	Pollen Type & Family	Size, Shape and Symmetry	Apertures	Pollen Surface ornamentation
1	Mimosa pudica Linn. (Mimosaceae)	8-12µm in diameter pollen grains in tetrahedral tetrads; spheroidal; radially symmetrical.	Individual grains provided with 4- 5 pores.	Exine 1µm thick, tectate, surface psilate.
2	Cleome viscosa Linn. (Cleomaceae)	Pollen grains are in monads ,24-26 µm, Amb sub spheroidal, 29-35 × 24-26 µm, sub prolate, isopolar, radial symmetry.	Tri-colporate, colpi narrowly elliptic, tips acute, margin incrassate, ora La-longate.	Exine 2.4 µm thick, subtectate, eixine ornamentation striate- reticulate.
3	Tribulus terrestris Linn. (Zygophyllaceae)	Pollen grains are in monads ,55-59 µm spheroidal, isopolar, radially symmetrical.	Pantoporate, pores numerous, 30 or more, placed in the lumina of the reticulum, there being one pore,1.8 – 2.25 µm in diameter.	Exine is 6.5 µm thick, prominently sub tectate, surface reticulate, pila of two types, narrow and broad, lumina polygonal and more or less of same size.
4	Lantana camara Linn. (Verbenaceae)	Pollen grains are in monads, 36 µm. amb more or less triangular, 37X39 µm oblate- spheroidal, isopolar, Radial Symmetry.	Tri-colporate, colpi long, Ora distinct, la-longate.	Exine 2.7 µm, thick, Tectate, Ornamentation psilate.
5	Commelina benghalensis Linn. (Commelinaceae)	Pollen grains are in monads ,16.5 µm, amb circular,13.5-17 × 16-17 µm, euoblate, monosulcate, heteropolar, bilateral symmetry	Monosulcate, Colpi elliptic, 21- 24 µm long,6.25 – 9.25 µm wide, margins ill- defined and jagged	Exine 1-1.5 µm thick, surface microechinate, echinae arranged in definite parallel lines on exine surface.
6	Zizyphus mauritiana Lam. (Rhamnaceae)	Pollen grains are in monads, 24 µm , Amb rounded triangular, 24-28 X 20-24µm, subprolate, isopolar, radially symmetrical.	3- zonocolporate, colpi tapering, margins thick, ora la-longate.	Exine 1.5 µm thick, tectate, sexine thinner than nexine, surface psilate, to locally granular.
7	Cardiospermum halicacabum Linn. (Sapindaceae)	Pollen grains are in monads,52-57 µm, amb triangular with straight sides and protruding pores at the angles, 26-30 × 47- 56 µm, oblate or peroblate, irregular symmetry,one polar area bulging the other more or less flattened	Triporate, pores 9 µm in diameter, proximal side of the grain is provided with a distinct triradiate scar in the centre, the branches of which can be traced as faint lines right up to the pores.	Exine 2.5 µm thick, sub-tectate, surface coarsely reticulate,lumina 2-3 µm across.
8	Datura stramonium Linn. (Solanaceae)	Pollen grains are in monads, 52 µm, Amb circular, 57-65 × 41-47 µm, Prolate, isopolar, radially symmetrical.	Trizonocolporate, colpi faint, linear,14.5 µm long, 1.5 µm wide towards equator, tips acute.	Exine 1.5 µm thick, tectate, exine ornamentation striate – reticulate, columellae distinct

 

 

 

 

5. Discussion

The Nizamabad district, located in Telangana state, comprises an agricultural expanse of approximately 2,02,587 hectares, where major crops include paddy, maize, turmeric, mangoes, pulses, soybeans, sunflowers, and onions. Pollen studies of the locally found weeds in these agricultural or cultivated areas plays an important role in identifying these unwanted plants. An analysis of pollen from various weed species collected during 2022-2023 from Nizamabad district in Telangana revealed a wide range of characteristics. Palynological analysis of eight weed plants viz., Mimosa pudica, Cleome viscosa, Tribulus terrestris, Lantana camara, Commelina benghalensis, Ziziphus mauritiana, Cardiospermum halicacabum and Datura stramonium belonging to eight families was carried out. Pollen types studied showed variations in their morphological features. All the grains are in monads except Mimosa pudica in which the pollen grains are in tetrads and the amb ranged from spheroidal, sub- spheroidal and rounded- triangular. The overall shape of the pollen ranged from prolate to oblate-spheroidal to oblate to peroblate. The apertural pattern varied in the taxa studied and is indicated by tricolporate condition in Cleome viscosa, Lantana camara, Ziziphus mauritiana and Datura stramonium, triporate in Cardiospermum helicacabum and Mimosa pudica, pantoporate in Tribulus terrestris and monosulcate in Commelina benghalensis. Antonio-Domingues et al. (2018) studied the pollen of Mimosa pudica from brazil and reported tetrad, triporate and psilate pollen characters. Naimat et al. (2012) highlighted the pollen characters of Ziziphus mauritiana as tricolporate and often Psilate exine. The exine ornamentation diversity in the present study is exhibited by Psilate in Mimosa pudica, Lantana camara and Ziziphus mauritiana, Striate-reticulate in Datura stramonium, Cleome viscosa, Reticulate in Tribulus terrestris, Cardiospermum helicacabum and Microechinate pattern in Commelina benghalensis. Plate 1 and Plate 2 represents the photomicrographs of the pollen types studied.

Plate 1

Plate 1 Showing Photomicrographs of the Pollen Types of Weedy Flora
S. No	Weed plant	Pollen P. V	Pollen E. V
1
	Mimosa pudica	Mimosa pudica P. V	Mimosa pudica E. V
2
	Cleome viscosa	Cleome viscosa P. V	Cleome viscosa E. V
3
	Tribulus terrestris	Tribulus terrestris P. V	Tribulus terrestris E. V
4
	Lantana camara	Lantana camara P. V	Lantana camara E. V

 

Plate 2

Plate 2 Showing Photomicrographs of the Pollen Types of Weedy Flora.
5
	Commelina benghalensis	Commelina benghalensis P. V	Commelina benghalensis E. V
6
	Ziziphus mauritiana	Ziziphus mauritiana P. V	Ziziphus mauritiana E. V
7
	Cardiospermum halicacabum	Cardiospermumhalicacabum P. V	Cardiospermum halicacabum E. V
	Datura stramonium	Datura stramonium P.V	Datura stramonium E.V

 

Authors’ Contribution

Conceptualization, design, data analysis and interpretation of results (PC); Sample collection and pollen slide preparation (NKG). Photomicrography (MC).

 

CONFLICT OF INTERESTS

None. 

 

ACKNOWLEDGMENTS

The authors are grateful to the Principal, University College of Science, Saifabad, Osmania University Hyderabad for providing the laboratory facilities.

 

REFERENCES

Antonio-Domingues, H., Corrêa, A. M. S., Queiroz, R. T., & Bitar, N. A. B. (2018). Pollen Morphology of Some Fabaceae Species from Patos de Minas, Minas Gerais State, Brazil. Hoehnea, 45(1). https://doi.org/10.1590/2236-8906-54/2017

Erdtman, G. (1952). Pollen Morphology and Plant Taxonomy of Angiosperms. Almquist and Wiksell, Stockhol M. https://doi.org/10.1080/11035895209453507

Erdtman, G. (1960). The Acetolysis Method. A Revised Description. Seven. Botan. Tdskr, 54, 561-564.

Erdtman, G. (1971). Pollen Morphology and Plant Taxonomy of Angiosperms. Hafner Publishing Co, New York.

Erdtman, G. (1978). Handbook of Palynology: Morphology, Taxonomy, Ecology. An Introduction to the Study of Pollen Grains and Spores.

Gamble, J.S., & Fischer, C.E.C. (1915 - 1936): Flora of the Presidency of Madras, London. https://doi.org/10.5962/bhl.title.21628

Jafari, E., & Ghanbarian, G. (2007). Pollen Morphological Studies on Selected Taxa of Asteraceae J. Plant Sci., 2, 195-201. https://doi.org/10.3923/jps.2007.195.201

Moore, P.D., & Webb, J.A. (1978). An Illustrated Guide Pollen Analysis Hodder and Stoughton, London.

Murthy, B.G., & Prathiba, N.C. (1995). Study on Weed Flora in Dryland Condition. World Weeds, 2, 175-177.

Naimat, R., Khan, M. A., Khan, K. Y., Ali, B., Zahidullah, & Mazari, P. (2012). Palynomorphological Characterization of Some Species of Selected Genera of Family Rhamnaceae. Research in Plant Biology, 2(3), 04-09.

Pullaiah, T., & Rao, B. R. (1995). Flora of Nizamabad District of Andhra Pradesh, India. Publishers Bishen Singh Mahendra Pal Singh.

Punt, W., Hoen, P.P., Blackmore, S., Nilson, S., & Thomas A.L. (2007). Glossary of Pollen and Spore Terminology. Rev.Palaeobot. Palynol., 143, 1-81. https://doi.org/10.1016/j.revpalbo.2006.06.008

Sharma, M. (1978). Weed Flora of Punjab in Rabi Crops. Indian J. Weed Sci. 10 (1&2), 15-18.

Tadulingam, C. (1955). A Hand Book of Some South Indian Weeds. Printed By the Superintendent Government Press, Madras.

Usma, A., Ahmad, M., Zafar, M., Sultana, S., Ullah, F., Saqib, S., Ayaz, A., & Zaman, W. (2022). Palynological Study of Weed Flora from Potohar Plateau. Agronomy, 12(10). https://doi.org/10.3390/agronomy12102500