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Many monocots are herbaceous and do not have the ability to increase the width of a stem (secondary growth) via the same kind of vascular cambium found in non-monocot woody plants. [35] However, some monocots do have secondary growth; because this does not arise from a single vascular cambium producing xylem inwards and phloem outwards, it is ...
Walnut shoot cut longitudinally to show the chambered pith found in this genus. Scale in millimeters. Pith, or medulla, is a tissue in the stems of vascular plants. Pith is composed of soft, spongy parenchyma cells, which in some cases can store starch. In eudicotyledons, pith is located in the center of the stem
The evolution of having one or two cotyledons may have arisen 200-150 Mya when monocots and dicots are thought to have diverged. [ 3 ] [ 4 ] Furthermore, the cotyledons in dicot seeds contain the endosperm which acts as the seed’s food storage, while in monocot the endosperm is separated from the cotyledon. [ 1 ]
Vascular cambia are found in all seed plants except for five angiosperm lineages which have independently lost it; Nymphaeales, Ceratophyllum, Nelumbo, Podostemaceae, and monocots. [1] In dicot and gymnosperm trees, the vascular cambium is the obvious line separating the bark and wood; they also have a cork cambium.
They can cause plant disease and can infect a broad range of hosts in several monocot and dicot plant families. [3] Smuts are cereal and crop pathogens that most notably affect members of the grass family and sedges . Economically important hosts include maize, barley, wheat, oats, sugarcane, and forage grasses.
Typically hyphae can be seen in the pith and cause blackening and necrosis. [ 6 ] [ 9 ] Infection can proceed rapidly once the pathogen has made an entrance into the plant. Once established, further reproduction of both chlamydospores and sporangia will occur within host tissues, amplifying the spread of disease within the host plant and ...
The disease is known as southern wilt, bacterial wilt, and brown rot of potato. Many more dicots suffer from the disease than do monocots. Among the monocot hosts, the order Zingiberales dominates, with five of nine families being infected by this bacterium. [2] The reason why some families are more susceptible to bacterial wilt is still unknown.