Plant biotechnology includes applications of technological tools in plant sciences. Several significant achievements in plant biology such as cell and tissue culture, regeneration of whole plants from somatic cells, and genetic recombination have resulted in applications such as rapid propagation, developing uniform healthy plant saplings, somatic hybrids from naturally incompatible species, germ plasm storage, improved transgenic plants, and so on. Observation that plant secondary metabolites accumulate in cultures in quantities larger than in intact plants, opened up possibilities of exploring such production as an economically viable alternative to their conventional extraction from whole plants. Resulting extensive work has thrown light on the many facets of plant secondary metabolism. Plant growth and its sustenance is now understood to be based on a wonderfully complex and dynamic interaction between the plant cell milieu and its environment. Plants are revealing themselves to be highly sensitive organisms as well, able to gauge their environment and adapt themselves physiologically and biochemically in accordance to external stimuli. Secondary metabolites are bio-synthesized by complex and multiple cascade of metabolic reactions triggered by several different enzymes. They are so made, in specialized cell types at distinct developmental stages. Presence of morphologically organized structures both for their synthesis and storage appear essential in many plants. Hence, though there have been spectacular advancements in crop improvement with profound implications in agriculture, forestry, and horticulture, development of transgenic plants producing required large quantities of secondary metabolites is still a distant possibility. As of today, however, few pharmaceuticals of interest like shikonin, ginseng, and taxol are being industrially produced in plant-tissue culture. Also, cultured plant cells are being used to effect economically useful chemical conversions on added precursors.

Still, many more hurdles are to be crossed and many more discoveries awaited before plant cells could be used as factories to generate the needed phytopharmaceuticals.