PLANT DEVELOPMENT

a multiphasic process in which two distinct forms succeed each other in alternating generations. One form, created by the union of sexual cells (gametes), contains two sets of similar chromosomes (diploid). At sexual maturity, this form, called the sporophyte, produces an offspring (gametophyte) with cells containing only one set of genetic instructions (haploid). At their sexual maturity, gametophytes produce haploid gametes that unite to begin a new cycle. Although both plants and animals share the chemical basis of inheritance and of translation of the genetic code into structural units called proteins, plant development differs from that of animals in several important ways. Higher plants sustain growth throughout life and, in this sense, are perpetually embryonic; animals, on the other hand, generally have a determinate period of growth, after which they are considered mature. Furthermore, both growth and organ formation in plants are influenced by their possession of a rigid cell wall and a fluid-filled space called the vacuole, two features unique to the plant cell. Conversely, certain features of animal cells are absent in plants. Notable is the lack of cellular movements and fusions that play an important part in tissue and organ development in higher animals. Additional reading Jir ebnek (ed.), Plant Physiology, trans. from Czech (1992), covers plant growth, development, and the resistance of plants to unfavourable abiotic and biotic effects. Lincoln Taiz and Eduardo Zeiger, Plant Physiology (1991), includes treatment of plant developmental processes; as does P.F. Wareing and I.D.J. Phillips, Growth and Differentiation in Plants, 3rd ed. (1981). Kalliopi A. Roubelakis-Angelakis and Kiem Tran Thanh Van (Thanh Van Kiem Tran) (eds.), Morphogenesis in Plants: Molecular Approaches (1993), presents advances in molecular and cellular biology pertaining to plant morphogenesis with particular reference to alternative approaches in solving difficulties of plant morphogenic expression. Jir ebnek, Zdenek Sladk, and Stanislav Prochzka (eds.), Experimental Morphogenesis and Integration of Plants (1991; originally published in Czech, 1983), addresses morphogenesis and structural integration in plants including possible ways of regulating these processes with regard to the practical needs of agriculture, horticulture, and silviculture.Specific topics are treated in Roger V. Jean, Mathematical Approach to Pattern and Form in Plant Growth (1984; originally published in French, 1983); Clive W. Lloyd (ed.), The Cytoskeleton in Plant Growth and Development (1982); F.A.L. Clowes, Morphogenesis of the Shoot Apex (1972), a thorough discussion of the development and structure of the apical meristem; Thomas A. Hill, Endogenous Plant Growth Substances, 2nd ed. (1980), a historical look at the discovery and significance of plant hormones; L.W. Roberts, P.B. Gahan, and R. Aloni, Vascular Differentiation and Plant Growth Regulators (1988); Thomas C. Moore, Biochemistry and Physiology of Plant Hormones, 2nd ed. (1989), a thorough account of hormonal regulation of growth and seed plant development; Richard N. Arteca, Plant Growth Substances: Principles and Applications (1996), a comprehensive reference on the regulation and manipulation of plant growth and development by plant growth substances; Karl J. Niklas, Plant Allometry: The Scaling of Form and Process (1994), the application of allometry to the studies of evolution, morphology, physiology, and reproduction of plants; Onkar D. Dhingra and James B. Sinclair, Basic Plant Pathology Methods, 2nd ed. (1995), a compilation of techniques applicable to the study of pathogens that infect plants, with more than 1,800 literature citations that can serve as research sources; B.M. Johri (ed.), Embryology of Angiosperms (1984); V. Raghavan, Embryogenesis in Angiosperms: A Developmental and Experimental Study (1986), on the various types of embryogenesis, their structural and biochemical aspects, and the experimental procedures used to elucidate pathways of development; L.T. Evans, Daylength and the Flowering of Plants (1975), an excellent treatment of the process of flower initiation and development and detailed discussion of photoperiodism; Richard E. Kendrick and Barry Frankland, Phytochrome and Plant Growth, 2nd ed. (1983); August De Hartogh and Marcel Le Nard (eds.), The Physiology of Flower Bulbs (1993); and J. Derek Bewley and Michael Black, Seeds: Physiology of Development and Germination, 2nd ed. (1994), covering in chronological sequence the most important events in seed development and the maturation, germination, and postgermination stages of seedling establishment.