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Laticifers

The document discusses different types of secretory tissues in plants, specifically laticifers. Laticifers are specialized parenchyma cells that transport latex, a suspension containing various substances like resins, proteins, oils, alkaloids and sugars. Laticifers can be non-articulate or articulate. Non-articulate laticifers are long multinucleated cells that branch extensively through tissues. Articulate laticifers form longitudinal chains of cells joined end to end, resembling xylem vessels. Articulate laticifers can be non-anastomosing or anastomosing, where the latter form net-like reticula through lateral connections. Specific plant families and examples of

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Presented by:- Surender Kaur B.Sc 3rd sem Uid-190606001
 Tissue  1. Meristematic 2. Permanent tissue tissue a. Simple b. Complex c. Secretory 1.parenchyma 1.xylem 1. External secretory 2.collenchyma 2.phloem structures 3.sclernchyma 2. Internal secretory structure
Secretory Tissue  many substance are released from the cytoplasm of the cells  Among these secretion some are beneficial to the plant some are not  These substance are called secretions and the cells/tissues concerned with these secretions are called secretory tissues  The structure and chemical composition of secretions varies  Secretion may be water, nectar, salt, tannins, resins, latex, gums, digestive enzymes, hormones etc.
Types of secretory tissue 1.External secretory tissue Glandular trichomes Nectaries Hydathodes 2.Internal secretory tissue secretory cells glands resin ducts laticifers / laticiferous tissue
Laticifers / laticiferous tissue  Specialized parenchyma cells; living  Fused tube like cells filled with viscous fluid called latex  White in color / yellow( Papaveraceae and Cannabinaceae)/ colorless ( Moraceae)  Suspension contains various substances like waxes, resins, proteins, essential oils, alkaloids and sugars  Alkaloid-Papaver  Enzymes-Papaya  Latex-source of rubber (Hevea and Ficus)  Chicle (Achras); Papain (Corica)  Monocots - Dracaena
Cell structure of laticifers  Cells contain living protoplast  Vacuoles well developed  Vacuoles store latex  Cells usually multinucleate  Latex may be milky white , colored or colorless
Chemical composition of latex  Latex is a mixture of chemical compounds  Contains carbohydrates, organic acid, alkaloids, terpenes, resins and enzymes  Latex of Euphorbia mili contains dumbbell shaped starch grains  Latex of Papaverm somniferum contain alkaloids (morphine, codeine)  Latex of Carica papaya contain digestive enzyme popain  Latex of Hevea contain rubber  Latex of Achras saporta contain chicles  Rubber particles suspended in the latex
Types of laticifers  On the basis of structure and development- Nonarticulate latex ducts / Latex cells Articulate latex duct/ Latex vessels - Content and funtion of them are same and both may occur in same family
Types of laticifers
Nonarticulate latex ducts/ Latex cells  These are multinucleated cells of immeasurable length  Initials originates within the meristematic mass of embryo  Develops from single cell  This initials grow more rapidly than neighbouring cells and form highly branched systems in the intercellular space  Elongate by intrusive growth  Occupy intercellular spaces of other cells  Eg. Apocynaceae Asclepiadaceae Euphorbiaceae Urticaceae
Nonarticulate latex ducts  They originate as minute structures, elongate quickly and ramify in all directions of the plant by repeated branching ,but they not fuse together , thus no netted structure are formed as they are formed in articulate ducts  The walls of the ducts are soft and very often thick  These may be or may not be branched  Branched nonarticulated laticifers commonly occur in leaves. here they travel through the vascular bundles ramify in the mesophyll and often reach the epidermis  Unbranched non-articulated laticifres of Vinca and Cannabis occur in the primary phloem but are apperently absent in the secondry tissue
Types of Nonarticulate latex ducts / latex cells Non articulated unbranched laticifer Non articulated branched laticifer
a. Non-articulate unbranched laticifers  They develop into long ,more or less straight tubes  Eg:- Cannabaceae (Humulus , Cannabis) Apocynaceae (Vinca) Urticaceae (Urtica)
b. Non articulated branched laticifers  They branched repeatedly, each cell thus forming an immense system of tubes  Eg:- Asclepiadaeae (Asclepias, Cryptostegia) Euphorbiaeae (Euphorbia) Moraceae ( Ficus, Morus) Apocynaceae( Nerium oleander) Cyclanthaceae( Cyclanthus bipartitus)
Articulate latex ducts/ Latex vessels  Compound in origin : made up of number of cells, joined end to end to form longitudinal files of cells  These are living coenocytic cells  Initiation takes place in the ontogeny of plant  Resembles with xylem vessels ; joined together with end walls dissoled  Eg- Compositae, Euphorbiacece, Papaveraceae , Moraceae  Laticifer show various arrangement and a frequent association with the phloem
Articulate latex ducts  In Carica papaya the laticifer apparently occur not only in the phloem but also in the xylem
First pic shows both non articulate and articulate laticifers second shows only articulate laticifers
Types of articulate latex ducts /vessels  Articulated nonanastomosing laticifer Articulated anastomosing laticifer
A. Articulated nonanastomosing laticifer B. Articulated anastomosing latiifer
a.Articulated nonanastomosing laticifers  They consist of a series of long cell chainsor compound chains or tubes not connected with each other laterally  Eg:- Papaveraceae (Chelidonium) Convolvulaceae(Convolvulus,Dichondra) Sapotaceae (Achrassaota, Manilkarazapota) Musaceae (Musa) Liliaceae (Allium)
b. Articulated anastomosing laticifers  They form lateral anastomes with similar cell chains or tubes, all united into a netlike structure or reticulum  Eg:-Caricaceae (Carica papaya) Euphorbiaceae (Hevea, Manihot) Papaveraceae (Argemone,Papaver)
Lithocysts Cystolith which is a botanical term for outgrowths of the epidermal cell wall , usually of calcium carbonate , formed in a cellulose matrix in special cells called Lithocysts , generally in the leaf of plants it includes in genera of Acanthaceae plants in the family Urticaceae also form leaf cystolith , but only during their later flowering seed setting stages also in plants of family Cannabaceae- Cannabis and Moraceae – Ficus elastica
Laticifers
Laticifers
Laticifers
Laticifers