Plant cells vessel element

Amongst agricultural productions, wheat is the second most cultivated cereal plant worldwide. Wheat straw is the main by-product of cereal harvest and is primarily used as fodder for animals [1]. It consists of relatively large number of elements, including the actual fibers, parenchymal cells, vessel elements, and epi-... 

The movement of water and nutrients from the soil to the upper portions of a plant occurs primarily in the xylem. The xylem sap usually contains about 10 mol m-3 (10 mM)2 inorganic nutrients plus organic forms of nitrogen that are metabolically produced in the root. The xylem is a tissue of various cell types that we will consider in more detail in the final chapter (Section 9.4B,D), when water movement in plants is discussed quantitatively. The conducting cells in the xylem are the narrow, elongated tracheids and the vessel members (also called vessel elements), which tend to be shorter and wider than the tracheids. Vessel members are joined end-to-end in long... 

M. Tarkow Yes, but how do they get into the interior Is there any relationship between the porosity of the vessels within the plants and the ability of the organism to get into the cell wall You have vessel elements, and these I understand are quite large in diameter. ... 

Senescence in plants is seen to occur in several ways. When a plant ages, its tissues cannot heal as rapidly and it is much less likely to defend itself against disease. Xylem vessel elements and cork cells age and die before they can assume their intended functions (Campbell et al., 1999). Eventually, this decline leads to death. Some plants die after one reproductive cycle (annuals), others after many cycles (perennials). 

The induction of PAL activity at the onset of vascular differentiation can be shown by the use of plant tissue cultures (37-39). Xylem cells with secondary and lignified walls are differentiated over a time course of 3-14 days by the application of the plant growth factors naphthylene acetic acid (NAA) and kinetin in the ratio 5 1 (1.0 mg/liter NAA, 0.2 mg/liter kinetin) to tissue cultures of bean cells (Phaseolus vulgaris) (37,40). The time for differentiation varies with the type of culture, solid or suspension, and with the frequency and duration of subculture, but for any one culture it is relatively constant (37,41,42). At the time of differentiation when the xylem vessels form, the activity of PAL rises to a maximum. The rising phase of the enzyme activity was inhibited by actinomycin D and by D-2,4-(4-methyl-2,6-dinitroanilino)-N-methylpropionamide (MDMP) applied under carefully controlled conditions (42). This indicated that both transcription and translation were necessary for the response to the hormones. Experiments using an antibody for PAL and a cDNA probe for the PAL-mRNA have also shown that there is an increase in the amount of transcript for PAL during the formation of lignin when Zinnia mesophyll cells are induced to form xylem elements in culture (Lin and Northcote, unpublished work). 

Copper is an essential element. Copper plays a significant role in several physiological processes - photosynthesis, respiration, carbohydrate distribution, nitrogen reduction and fixation, protein metabolism, and cell wall metabolism. Many plant metalloenzymes contain copper. It also influences water permeability of xylem vessels and thus controls water relationships. It is mainly complexed with organic compounds of low molecular weight and with proteins (Henze and Umland, 1987). Kabata-Pendias and Pendias (1984) have compiled data on the Cu concentrations in... 

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