Leaf hairs

Experiment 8. The observation of the secretory hairs and their secretion Cell-donor of allelochemicals releases the substances out. The process may be seen with the help of LSCM technique as the study of the fluorescence of various external secretory structures. Such structures are glandular cells, which contained many potentially fluorescent substances (Roshchina and Roshchina, 1993). One of the example is shown for secretory leaf hair of allelopathically active species Solidago virgaurea L. (Fig.ll). 

Fig. 11 The LCSM images of the secretory leaf hair of Solidago virgaurea L. The stack of... 

Quercus ilex Leaf hairs Acylated kaempferol glycosides 102... 

Skaltsa, H. et al., UV-B protective potential and flavonoid content of leaf hairs of Quercus ilex. Phytochemistry, 37, 987, 1994. 

Ehleringer, J.R., and Mooney, H.A. 1978. Leaf hairs Effects on physiological activity and adaptive value to a desert shrub. Oecologia 37 183-200. 

Leaf Hairs—A dense layer of leaf hairs holds the herbicide droplets away from the leaf surface, allowing less chemical to be absorbed into the plant. A thin layer of leaf hairs causes the chemical to stay on the leaf surface longer than normal, allowing more chemicals to be absorbed into the plant. 

Karaboumiotis, G., Papadopoulos, K., Papamarkou, M. Manetas, Y. (1992). Ultraviolet-B radiation absorbing capacity of leaf hairs. Physiologia Plantarum, 86, 414-418. 

It could concluded that, because of this difference in plant Se speciation, the tissue Se sequestration pattern is different for hyperaccumulators, where they store Se mainly in the leaf epidermis (sometimes in leaf hairs) and in reproductive tissues, particularly pollen, ovules and seeds (Quinn et al. 2011). About nonhyperaccumulators mainly store Se in vascular tissues of leaves, and have higher Se levels in leaves than flowers (Quinn et al. 2011). It could be converted methyl-SeCys to dimethyldiselenide, where it is the main form of volatile Se produced by hyperaccumulators. On the other hand, non-hyperaccumulators produce volatile dimethylselenide, using selenomethionine (SeMet) as a starting point (Terry et al. 2000). Plant levels of Se also show different seasonal fluctuations in hyperaccumulators and non-accumulators, where the leaf Se concentration is highest in the early spring for hyperaccumulators, but peaks in summer for non-hyperaccumulators (Galeas et al. 2007). The seasonal fluctuations in Se levels are correlated with S levels for non-hyperaccumulators, but not for hyperaccumulators as reviewed by El Mehdawi et al. (2012). 

Turning to exchange between the canopy and the underlying soil, sedimentation processes are of primary importance. This includes deposition via precipitation, whereby, as outlined above, organic chemicals can be transported dissolved in the water, associated with particles trapped in the precipitation, or sorbed to the surface of the water/ice. The chemical fluxes below the canopy are, however, much more difficult to estimate than the wet deposition to the canopy, due to the interactions between the precipitation and the canopy. When a raindrop hits a leaf, some of the chemical dissolved in the rain may sorb to the leaf, but on the other hand, chemical already present on the leaf may dissolve in the rain. Similarly, particles in a raindrop may be retained on the leaf surface (for instance by leaf hairs), or particles which had already accumulated on the leaf surface (for instance via dry deposition) may be... 

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