Skip to main content Accessibility help

Micromorphology of Johnsongrass (Sorghum halepense) Leaves

  • Chester G. Mcwhorter (a1), Clark Ouzts (a1) and Rex N. Paul (a2)


Adaxial and abaxial epidermal surfaces of johnsongrass leaves were studied to determine which cells contribute to leaf microroughness. Cork-silica cell (CSC) pairs, three types of prickles, macrohairs, bicellular trichomes, stomata, and ordinary short and long epidermal cells were found and described. CSC pairs made up about 22% of all cells and probably contribute more to microroughness than any other single type because each cork cell produces 11 ± 3 wax filaments that are up to 100 μm long. Bicellular trichomes represented 4 to 5% of the total cells but decreased leaf roughness by secreting a type of mucilage that covers microscopic wax crystals. Stomatal complexes comprised 15 to 18% of all cells and contributed to leaf roughness because they are slightly recessed below the leaf surface. Long prickles occur primarily over veins and represent less than 1% of all cells. Small prickles were present primarily on adaxial surfaces and represent only 3% of all cells. Macrohairs were the largest appendages, 237 ± 104 μm, but they represent far less than 1% of all cells and occur primarily over veins. Ordinary short cells comprised 6 to 13% of all cells. Long cells were most common (41%) of all cells. Short and long cells contribute to leaf roughness because the surface is often convex. A typical johnsongrass leaf may contain more than 25 million appendages on each surface that increase the roughness already caused by epicuticular wax crystals.



Hide All
1. Amarasinghe, V. and Watson, L. 1988. Comparative ultrastructure of microhairs in grasses. Bot. J. Linn. Soc. 98:303319.
2. Araus, J. L., Febrero, A., and Vendrell, P. 1991. Epidermal conductance in different parts of durum wheat grown under Mediterranean conditions: the role of epicuticular waxes and stomata. Plant Cell Environ. 14:545558.
3. Baker, E. A., Hunt, G. M., and Stevens, P.J.G. 1983. Studies of plant cuticle and spray droplet interactions: a fresh approach. Pestic. Sci. 14:645658.
4. Boize, L., Gudin, C., and Purdue, C. 1976. The influence of leaf surface roughness on the spreading of oil spray drops. Ann. Appl. Biol. 84:205211.
5. Borikar, S. T. and Chundurwar, R. D. 1989. Genetic analysis for trichome density in Sorghum bicolor (L.) Moench. J. Maharashtra Agric. Univ. 14:304305.
6. Burton, G. W., Hanna, W. W., Johnson, J. C. Jr., Bueck, D. B., Monson, W. G., Powell, J. B., Wells, H. D., and Widstrom, N. W. 1977. Pleiotropic effects of the tr trichomeless gene in pearl millet on transpiration, forage quality, and pest resistance. Crop Sci. 17:613616.
7. Chambers, G. V., Bulawa, M. C., McWhorter, C. G., and Hanks, J. E. 1992. Use of surface relationship models to predict the spreading of nonaqueous droplets on johnsongrass. Am. Soc. Test. Mat. STP 1112 11:218246.
8. Cutter, E. G. 1978. Pages 821, 94–143, 214–241 in Plant Anatomy. Addison-Wesley Publishing Company, London.
9. Dybing, C. D. and Currier, H. B. 1961. Foliar penetration by chemicals. Plant Physiol. 36:169174.
10. Ellis, R. P. 1979. A procedure for standardizing comparative leaf anatomy in the Poaceae. II. The epidermis as seen in surface view. Bothalia 12:641671.
11. Fahn, A. 1974. Pages 165198, 235–282 in Plant Anatomy. 2nd ed. Pergamon Press, Oxford, UK. 611 pp.
12. Fahn, A. 1988. Tansley review no. 14: Secretory tissue in vascular plants. New Phytol. 108:229257.
13. Field, R. J. and Bishop, N. G. 1988. Promotion of stomatal infiltration of glyphosate by an organosilicone surfactant reduces the critical rainfall period. Pestic. Sci. 24:5562.
14. Gudin, C., Syratt, W. J., and Boize, L. 1976. The mechanisms of photosynthetic inhibition and the development of scorch in tomato plants treated with spray oils. Ann. Appl. Biol. 84:213219.
15. Hess, F. D., Bayer, D. E., and Falk, R. H. 1974. Herbicide dispersal patterns: I. As a function of leaf surface. Weed Sci. 22:394401.
16. Jefferson, P. G., Johnson, D. A., and Rumbaugh, M. D. 1988. Genetic analysis of epicuticular wax production in alfalfa. Genome 30:896899.
17. Johnson, H. B. 1975. Plant pubescence: an ecological perspective. Bot. Rev. 41:233258.
18. Juniper, B. E. and Jeffree, C. E. 1983. The anatomy, ultrastructure, and biosynthesis of the plant surface. Pages 1036 in Plant Surfaces. Edward Arnold, Ltd., London.
19. Kaufman, P. B., Dayanandan, P., Franklin, C. I., and Takeoka, Y. 1985. Structure and function of silica bodies in the epidermal system of grass shoots. Ann. Bot. 55:487507.
20. Kaufman, P. B., Petering, L. B., Yocum, C. S., and Baic, D. 1970. Ultrastructural studies on stomata development in internodes of Avena sativa . Am. J. Bot. 57:3349.
21. Lanning, F. C. and Eleuterius, L. N. 1989. Silica deposition in some C3 and C4 species of grasses, sedges, and composites in the USA. Ann. Bot. 63:395410.
22. Martin, J. T. and Juniper, B. E. 1970. Pages 223253 in The Cuticles of Plants. Edward Arnold, Ltd., London.
23. McWhorter, C. G. 1971. Anatomy of johnsongrass. Weed Sci. 19:385393.
24. McWhorter, C. G. 1989. History, biology, and control of johnsongrass. Rev. Weed Sci. 4:85122.
25. McWhorter, C. G. and Paul, R. N. 1989. The involvement of cork-silica cell pairs in the production of wax filaments in johnsongrass (Sorghum halepense). Weed Sci. 37:458470.
26. McWhorter, C. G., Ouzts, C., and Hanks, J. E. 1993. Spread of water and oil droplets on johnsongrass (Sorghum halepense) leaves. Weed Sci. 41:460467.
27. McWhorter, C. G., Paul, R. N., and Barrentine, W. L. 1990. Morphology, development, and crystallization of epicuticular waxes on johnsongrass (Sorghum halepense). Weed Sci. 38:2233.
28. Metcalfe, C. R. 1960. Pages xvlix in Anatomy of the Monocotyledons. Oxford Univ. Press, London.
29. Ormrod, D. J. and Renney, A. J. 1968. A survey of weed leaf stomata and trichomes. Can. J. Plant Sci. 48:197209.
30. Paul, R. N. and McWhorter, C. G. 1990. Correlation of ultrastructure with the mechanism of wax filament production in cork cells in johnsongrass [Sorghum halepense (L.) Pers.]. Proc. Int. Congr. Elect. Micro. 12:676677.
31. Paul, R. N., McWhorter, C. G., and Ouzts, J. C. 1992. An investigation into the ultrastructural histochemistry of glandular trichomes of johnsongrass [Sorghum halepense (L.) Pers.] leaves. Elect. Micro. Soc. Am. 50:842843.
32. Rodriguez, E., Healey, P. L., and Mehta, I. 1984. Pages 7194, 133–240 in Biology and Chemistry of Plant Trichomes. Plenum Press, New York.
33. Tischler, C. R. and Voigt, P. W. 1990. Variability in leaf characteristics and water loss in the weeping lovegrass complex. Crop Sci. 30:111117.
34. Xu, A., Lu, P., and Wang, X. 1990. Silica cells and silica bodies in vegetative organ of sorghum (Sorghum vulgare Pers.). Acta Agron. Sin. 16:5764.


Micromorphology of Johnsongrass (Sorghum halepense) Leaves

  • Chester G. Mcwhorter (a1), Clark Ouzts (a1) and Rex N. Paul (a2)


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed