Deciduous , from Latin caducus ('decrepit, fallen 'participle cadere 'falling') and folium ('leaf') refers to trees or shrubs that lose their foliage for part of the year, which coincides in most cases with the arrival of the unfavorable season, the coldest season (winter) in temperate climates. However, some lose their foliage during the dry season in the hot, arid climates.
They are also called deciduous , as opposed to trees called evergreen . In Puerto Rico, the influence of American culture , is also known as deciduous , tracing the English deciduous . In turn, the root of this word refers to the Latin deciduus derived from decided , 'to fall, die.'
Many deciduous trees and shrubs bloom during the period when no leaves, as this increases the effectiveness of pollination . The absence of sheets benefits dispersion pollen by wind or, in the case of plants pollinated by insects , which the flowers are more visible by the latter. However, this strategy is not without risk, since the flowers can be damaged by ice or in areas with dry seasons, plants may expire with this effort.
In botany , the cap , tip cap or calyptra is conical coverage surrounding the apex of the root . Usually not visible to the naked eye and consists of undifferentiated soft tissue. The root cap covers, protecting, or meristematic tissue growth, as proliferation by mitosis originate cells , after differentiation, form the adult structure of the root. Behind the meristem are parenchyma, vascular tissues and in those roots that must swell in subsequent years, the remaining meristems, responsible for secondary growth.
The root cap provides mechanical protection to the root meristem cells when grown through the soil. These cells are destroyed by the root growth and friction with the ground, but are quickly replaced by new cells generated by cell division in the outer face of the root meristem. The root cap is also involved in the production of mucilage , a gelatinous substance that covers the newly formed meristematic cells. These cells contain statoliths , which are starch grains which are inside the cell and are very dense, so that they move in response to the force of gravity , providing the following information necessary for their growth.
The root cap consists of living parenchyma cells which often contain starch . The cells are arranged in radial rows, cells form a central axis called the columella . The apical cells differ in peripheral cells with epidermal cells secrete mucigel , viscous substance composed mainly of polysaccharides produced in the dictyosomes . The peripheral cells emerge as the root breaks through the ground.
In botany , the chalice is the whorl outside in the flowers with perianth heteroclamideo, ie with two kinds of parts. It is composed of sepals , which are antofilos sterile and consistency usually green grass . It has protective function.
If the sepals are free from each other is called the cup dialisepalo , whereas if they are attached is called gamosepalous as in carnation ( Dianthus caryophyllus , Caryophyllaceae ) or seibo ( Erythrina crista-galli , legumes ).
When the cup is gamosepalous can distinguish three distinct parts: the tube , which is the portion in which the sepals are united, the throat , which is the site where the sepals are separated from each other, and the limb , which free potion is formed by the apical ends of each sepal or lobes.
The sepals may have varied texture and shading. In the composites, for example, sepals are reduced to hairs or bristles that constitute the so called pappus or pappus .
According to its duration with respect to the other floral parts, the cup can be ephemeral or fleeting , when the sepals fall to open the flower, as in the poppy ( Papaver rhoeas , poppies ), deciduous , when the sepals emerge after it has fertilization occurred, or persistent when it remains after fertilization and goes with the fruit, as in the case of apple ( Malus domestica , Rosaceae ). 1
The anatomy of the cup is, of all the floral pieces, the most reminiscent of the nomofilos (normal leaves). The cloud is usually formed by parenchyma clorofiliano homogeneous. Generally in each species, sepal is supplied by the same number of leaf traces showing the nomofilos.
Each year the cambium layers of cells gives rise to two adults. The first inland, is of wood ( xylem ) that form these are the wood and then recognized as growth rings. The second, out, is another type of tissue the phloem , which transports sap drawn towards the roots. The cambium is a meristem remaining primary , formed by a trail of embryonic cells derived from the apical meristem . Thereof, located at the end of growth, it also leaves behind adult tissues. The cambium is responsible for secondary growth in thickness of the stems, is a secondary meristem, consisting of adult cells back to regain their meristematic character.
In Botany, the resin canals are a type of secretory tissue found in higher plants. These are channels that secrete resin (a substance formed by a mixture of resin acids, oils and alcohols) whose function is to protect or defend the plants from attack by insect herbivores and fungi .
The resin canals are very abundant in conifers . In the pines are located in the xylem , in the transition zone between the wood early and late wood. Its secretion is called 'micron', whose distillation is obtained turpentine or turpentine (used as a solvent for paints and for the synthesis of various products such as lubricants , medicines and flavorings) and 'rosin' (used in the manufacture of inks and soaps). Commercial exploitation of 'resinaceous pine' ( Pinus pinaster ) was oriented to the extraction of resin for the manufacture of such products. Currently this practice rarely performed because the synthesis of similar products with the same function is cheaper to make from oil .