Shoot system

Apical or primary Meristematic cells Produce primary body of root-and-shoot system... 

There are two basic systems in a plant the shoot system, which includes above-ground elements such as leaves, stems, buds, and flowers and fruit (if there are any) and the root system, the underground parts, including roots, tubers, and rhizomes (Figure 4.1). 

In species, where the root does not provide an of cial drug, data on essential oil accumulation of the underground parts are obviously much rarer. Existing data, however, show that the composition of the underground parts might be similar or even totally different from that of the shoot system. 

The picture is somewhat similar for peppermint. According to investigations of Murray et al. (1988), components of the essential oil distilled from the stolons are highly comparable with the shoot oil. Major compounds of the stolon oil were menthofuran (46.1%), menthyl acetate (24.5%), and menthol (11.4%), which re ect only quantitative differences compared to the oil distilled from the herb or the leaves. These data refer to a relatively uniform biosynthetic process of these terpenoids in the whole shoot system developing underground or overground. 

To calculate the partiais we define shooting system dynamics for each unknown initial condition. These equations come from taking partiais with respect to the missing initial conditions (a and 6), of the describing state differential equations (7.2.1) to (7.2.4). 

Note that the initial conditions for the shooting systems follow directly from the initial conditions on the state system. Solving the state and shooting systems simultaneously gives the information needed to compute new initial conditions a +i and from equation (7.2.7) and... 

Figure 7.5b Dynamic model and Shooting System Equations,...

Develop the generalized shooting technique for solving this problem. Write down the shooting system dynamics for this problem and the updating equations for unknown initial conditions. Discuss a computer implementation. 

Carr DJ, Reid DM (1968) The physiological significance of the synthesis of hormones in roots and of their export to the shoot system. In Wightman F, Setterfield G (eds) Biochemistry and physiology of plant growth substances. Runge, Ottawa, pp 1169-1185... 

After feeding the tips of intact primary roots of Phaseolus seedlings with aqueous solutions of labeled hormones by means of 1 jil-droplets (which were quickly absorbed), percentages of 30, 10, 4, and 1 of the label from kinetin, ABA, GAi, and lAA, respectively, were translocated into the shoot system during the subsequent 24 h. Most of the shoot s kinetin label was detected in the apical bud and primary leaves, although in all cases radioactivity was found in lateral and adventitious roots, about 10% for the ABA and 3% for the other hormones (Hartung 1977). 

Plants intact except for the transverse wound regenerated numbers of vascular cells equivalent to those formed by about 0.05% lAA added to the isolated internode (asterisks in Fig. 4.9). Hence, 0.05% lAA in lanolin exactly replaced the root system and the rest of the shoot system in their effects on the regeneration of both sieve tubes and tracheary cells. At any one lAA level, more sieve cells than tracheary cells regenerated. 

As an extension of the preceding discussion about the probable consequences of interactions between auxin waves in branched shoot systems, a control mechanism capable of coordinated growth of all plant parts (axes) can be proposed. Vector fields in the zones of major polar transport of auxin in axes of various orders can be envisioned as morphogenic fields specifying positional information... 

Isolated axes of peas are not dependent on the reserve material of the cotyledons during the initial stages of radicle elongation [17]. Reserves of carbohydrate, protein and fat in the radicle itself must be sufficient for these early events, and sucrose, raffmose and stachyose probably serve as sources of respirable substrate. But after these early events have passed, the further development of the root and shoot systems depends upon the contributions from the cotyledons. Their stored carbohydrate (and the other reserves) are hydrolysed and transported into the axis. It is not yet clear if the initiation of mobilization is actually controlled by the embryonic axis this is discussed fully in Chapter 7. We can say, however, that the subcellular changes in the cotyledons that precede and accompany reserve mobilization do need the presence of axis, at least over the first 48 h after the start of imbibition. 

The major nematode pests are the root-attacking cyst nematodes. Other agriculturally important nematodes are the stem nematodes. These can have a wide host range but on each host they cause varying forms of necrosis and deformity of the shoot systems. These stem nematodes are often spread in contaminated seed or plant debris. 

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