'Anomalous 2ndary growth in dicot and monocot system\r'

'DICOT topic Plants display anomalous secondhand harvesting can be studied in two main groups. (1) Those in which cambium of commonplace type is present and persists only if by peculiarity or irregularity in its natural action develop vascular create from raw stuffs of unusual arrangement. (2) Those in which the normal cambium either does not develop or in soon replaced by another cambium. This abnormal cambium whitethorn either develop from cortex or pericycle and shows abnormal use.NORMAL CAMBIUM WITH ABNORMAL ACTIVITY: Aristolochia Stem: During secondary growth inhume and intra fascicular cambium becomes active and forms a ring. The inter fascicular cambium cuts vascular tissue and the inter fascicular cambium forms p benchyma. The strands thus perch discrete. The growth sound are visible in xylem. With the increase of secondary tissue pith and rays are partly crushed. This crushing is probably a egress of resistance offered to the expanding vascular system by the pe rivascular cylinder (pericycle).This slender alike breaks up subsequently nigh time at the rays. Adjacent parenchyma cells invade the breaks by intrusive growth and may differentiate into sclereide. The intra fascicular cambium at places forms parenchyma which results in the bifurcation of bundles phellogen is formed from the hypodermis. It is initiated as isolated vertical strips extending from node to node and takes several years to scattering over the entire surface. The bobfloat developed is overlying and con boldnessrable amount of phellogen (secondary cortex) is developed lenticles are also formed.ANOMALOUS SECONDARY GROWTH IN MONOCOT STEM In monocotyledons normally the vascular bundles are closed. The cambium organism absent the secondary growth is absent; but in some plants like dracaema and Yucca secondary growth takes place.Dracaens Stem:(1) The young stem has typical organise i.e. epidermis is followed by sclerenchymatous hypodermis. A large fare of closed colla teral bundles are scattered in ground tissue.(2) One of the outer layers of cells from the ground tissue becomes meristematic and functions as cambium. The cambium formed in the region which has ceased elongating.(3) The activity of this cambium is more on the midland side and in truth little on the outside where it forms only parenchyma. On the inner side it forms xylem and parenchyma in alternate patches. The inner parenchymatous cells are called conjunctive tissue.(4) After a get around while the activity of cambium on inner side changes and above the xylem is starts forming phloem and then again xylem. thus phloem becomes encircled by xylem and ring of leptocentric (amphibasal) vascular bundle is formed. The xylem formed front has bigger vessels.(5) some each vascular bundle is developed sclerenchymatous sheath.(6) The cambium after sometime alters its activity and forms xylem on the inner side, at those places where it was previously forming the parenchyma and parenchym a in place of xylem. Similar to earlier case again by change in activity it forms a ring of vascular bundles.(7) natural process of cambium goes on changing regularly and more rings of vascular bundles are formed.(8) The last one or two rings of vascular bundles lie in conjunctive tissue.(9) Cork cambium is formed below hypodermis and forms cork and cork cambium in normal fashion.\r\n'