Intact plant studies

Intact Plant Studies with Brassins - BARC. Because yields were not increased in the 1974-75 field studies by the brassins treatment procedure used, application techniques... 

Roshchina, V.V., Melnikova, E.V., Mitkovskaya L.I. and Karnaukhov, V.N. (1998). Microspectrofluorimetry for the study of intact plant secretory cells. Journal of General Biology (Russia). 59 531-554. 

All of the previous studies with cell suspension cultures of C. roseus have led to the conclusion that not all of the cells in suspension produce alkaloids, i.e., that some differentiation occurs. Neumann and co-workers at Halle 149) used fluorescence and electron microscopy to show that, like the intact plants, indole alkaloid accumulation occurs in the vacuoles of particular cells. Yet there appears to be no ultrastructural difference between these cells and those which do not produce alkaloids. It had been suggested earlier that basic alkaloids were accumulated by some kind of ion trap mechanism in acidic vacuoles (750). Indeed, a substantial pH difference was observed between those vacuoles which do accumulate alkaloids (pH 3) and those which do not (pH 5). It was concluded that the tonoplast of the alkaloid cells seemed to be highly permeable to the neutral form of the alkaloids, but only slightly permeable to the protonated forms. Cell lines which did not exhibit a difference in their vacuolar pH did not accumulate alkaloids. 

The 200GW line proved to be quite different, and of particular interest was the discovery that this line produced catharanthine (4) at levels about three times that of the intact plant (0.005%) (155,159,160). Curiously, the predominant alkaloid (60.48%) was strictosidine lactam (41), which is not normally seen in extracts of intact plants. Variation of the pH and added phytohormones did not significantly alter the pattern of alkaloids produced by this cell line (160). Further cell line studies (161) afforded one line (176G) which produced mainly ajmalicine (39) and lochnericine (73) and one (299Y) which apparently contained relatively inactive p-glucosi-dases, since the major alkaloids produced were strictosidine (33) (83%) and strictosidine lactam (41) (Table XIII). 

Incubation of geissoschizine (35) with a cell-free extract from C. roseus 210) in the presence of NADPH caused the accumulation of an isomer of isositsrikine whose structure was established chemically to be the (167 ) isomer 58. None of the 16-epi isomer 95 was detected in the cell-free incubations or in feeding experiments with intact plants. Additionally, Stdck-igt has reviewed enzymatic studies on the formation of strictosidine (33) and cathenamine (76) (277), and Zenk has provided a very elegant summary of the enzymatic synthesis of ajmalicine (39) (272). 

The only study of the biosynthesis of bisindole alkaloids in intact plants using advanced precursors was reported by Scott and co-workers in 1978... 

The conversion of anhydrovinblastine (8) to vinblastine (1) has been examined by several different groups, using intact plants, cell suspension systems, and cell-free preparations. From the studies discussed above it was clear that 3, 4 -anhydrovinblastine (8) was probably the initially formed intermediate in the condensation of vindoline (3) and catharanthine (4) prior to vinblastine (1). Kutney and co-workers have reported (225,226) on the biotransformation of 3, 4 -anhydrovinblastine (8) using cell suspension cultures of the 916 cell line from C. roseus a line which did not produce the normal spectrum of indole alkaloids. After 24 hr the major alkaloid products were leurosine (11) and Catharine (10) in 31 and 9% yields, respectively, with about 40% of the starting alkaloid consumed. 

In this chapter, we review our recent progress in establishing the exact bonding patterns of lignin in situ in intact plants. Presumably, similar strategies can be employed to study suberin structure. 

The use of hairy roots for the production of biopharmaceuticals has been studied extensively and has been discussed in Chapter 1 of this book. To date, over 116 different plant species have been induced to produce hairy roots in culture (Guillon, 2006). Originally, an expression system was developed for protein production based on the natural secretion from roots of intact plants. In order to take up nutrients from the soil, interact with other soil organisms, and defend themselves against numerous pathogens, plant roots have developed sophisticated mechanisms based upon... 

It is difficult to interpret many of the data on metal-binding components of plants because these have been determined from experiments on Cd-resistant, Cd-grown cell cultures. This presents two problems. First, plant cell cultures do not necessarily respond physiologically in the same way as intact plants, and secondly, Cd is not an essential metal and hence may not elicit the same responses as an essential one. Our studies thus aimed to examine whole plants, in particular roots, since this is the normal route of metal entry into the plant, and to compare essential with non-essential metal responses. 

In the last 40 years of research on HS biological activity, several aspects have been elucidated. The favorable morphological effects of HS on plants regarding growth enhancement have been demonstrated on several plant species under different study conditions. Besides these observations, effects on morphogenesis have also been demonstrated in terms of (a) the induction of lateral root formation and (b) root hair initiation and development in intact plants and stimulation of root and shoot development in treated cell calluses. 

It should be noted that in most of these studies, especially in those on the barley leaf discs, the metal concentrations applied are significantly higher than those found in the field. It remains, therefore, to be proven that the cadmium effects described occur at the metal concentrations present in intact plants growing in situ on a cadmium-contaminated substrate. 

Insofar as they have been studied, all herbicides that inhibit the Hill reaction of isolated chloroplasts also inhibit photosynthesis of intact plants and photosynthetic microorganisms (2, 3). Phy to toxicity is produced only in the light, and severity of symptoms is proportional to light intensity. Studies with light quality have indicated that the chlorophylls are the principal absorbing pigments involved in the production of phytotoxicity. 

However, in no case have such studies informed us of the chemical bases for the toxic reactions. Examinations of lesions in the field can lead to the identification of newly polluted areas and new pollutants. Experiments in the greenhouse and laboratory can determine the dose response in terms of pollutant concentration and duration of exposure. Physiological studies of intact plants can correlate metabolic changes with the development of toxic symptoms. If we are to understand fully the effects of air pollutants on plants, however, it is essential that we elucidate the biochemical mechanisms of their action. 

---