Influence of phytohormones

The hairy root cultures of Hyoscyamus species have been studied for alkaloid production by several researchers [3, 23, 24]. However, the influence of phytohormones and light on the production of tropane alkaloids in transformed roots of this genus has not been reported in detail. In this section, we describe the alkaloid production by H. albus hairy roots cultured under different conditions. 

The influence of phytohormones and light on the production of tropane alkaloids in transformed roots of Hyoscyamus albus was investigated [25]. In adventitious roots cultured in the dark, the addition of lAA (up to 4 mg/1) to the culture medium only slightly affected alkaloid production (Fig. 8a). On the other hand, when the adventitious roots were cultured under light, the alkaloid content decreased with the addition of lAA. Any combination of lAA with kinetin rapidly... 

Fig 8. Influence of phytohormones on alkaloid production by adventitious and hairy roots of Hyoscyamus aihus cultured in WP solid medium. Phytohormones were added either alone or in combination. Bars indicate standard error. 

Thus, changes in the prospective fruit tissue begin as early as pollination and the transfer of phytohormones associated with it. However, at the same time, the development of a partitioning layer beneath the flower, which is also under the influence of phytohormones, is inhibited, thus preventing premature fruit fall (page 199). 

The unusual amino acid, 1-aminocyclopropanecarboxylic acid, a precursor of the phytohormone ethylene, is biosynthesized in plants from S-adenosylmethionine. By using dideuterated S-adenosylmethionine, the reaction, under the influence of a pyridoxal phosphate dependent synthase, involves an inversion at the x-carbon center (a feature rarely observed for pyridoxal phosphate reactions), leading to (5)-l-amino-2,2-dideuterocyclopropanecarboxylic acid4. 

Danneberg G, Latus C, Zimmer W, Hundeshagen B, Schneider-Poetsch H, Bothe H (1992) Influence of vesicular arbuscular mycorrhiza on phytohormone balances in maize (Zea mays L.). J Plant Physiol 141 33-39... 

In order to study how a silatrane group which is present in phytohormones influences their activity we have investigated the action of silatranylmethyl esters of 2-methyl-phenoxyacetic, 4-chlorophenoxyacetic and 3-indolylacetic acids on the suspended cul-... 

Terpenoids, which are also known as isoprenoids, constitute the most abundant and structurally diverse group of plant secondary metabolites, consisting of more than 40,000 different chemical structures. The isoprenoid biosynthetic pathway generates both primary and secondary metabolites that are of great importance to plant growth and survival. Among the primary metabolites produced by this pathway are phytohormones, such as gibberellic acid (GA), abscisic acid (ABA), and cytokinins the carotenoids, such as chlorophylls and plastoquinones involved in photosynthesis the ubiquinones required for respiration and the sterols that influence membrane stmcture (see also Steroid and Triterpene Biosynthesis) (Fig. 1). Monoterpenoids (CIO), sesquiterpenoids (Cl5), diterpenoids (C20), and... 

Plant cell culture medium includes inorganic compounds and phytohormones. Changing the medium components (concentration, proportion, and form) is a very powerful way of enhancing the culture efficiency of plant cell cultures. Unsuitable conditions often reduce the efficiency. For example, high auxin levels can stimulate cell growth, but can often negatively influence secondary metabolite production. ... 

Standardization of medium is an important parameter in in vitro tissue culture technology since the composition of the culture media influences both the biomass yield as well as secondary metabolite production. Composition of the medium, culture conditions, and exogenous phytohormone combinations together influence the metabolite accumulation in the cell. Composition of macro- and micronutrients, nature and amount of carbon source, and level of total nitrogen has been found to play a vital role in the production of secondary metabolites. 

---