Laticifers

Anatomy of angiosperms: Laticifers

1. Laticifers Presented by:- Surender Kaur B.Sc 3 rd sem Uid-190606001

2. 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

3. 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.

4. Types of secretory tissue 1.External secretory tissue Glandular trichomes Nectaries Hydathodes 2.Internal secretory tissue secretory cells glands resin ducts laticifers / laticiferous tissue

5. 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

6. 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

7. 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

8. 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

9. Types of laticifers

10. 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

11. 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

12. Types of Nonarticulate latex ducts / latex cells Non articulated unbranched laticifer Non articulated branched laticifer

13. a. Non-articulate unbranched laticifers They develop into long ,more or less straight tubes Eg :- Cannabaceae ( Humulus , Cannabis) Apocynaceae ( Vinca ) Urticaceae ( Urtica )

14. 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 )

15. 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

16. Articulate latex ducts In Carica papaya the laticifer apparently occur not only in the phloem but also in the xylem

17. First pic shows both non articulate and articulate laticifers second shows only articulate laticifers

18. Types of articulate latex ducts /vessels Articulated nonanastomosing laticifer Articulated anastomosing laticifer

19. A. Articulated nonanastomosing laticifer B. Articulated anastomosing latiifer

20. 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 )

21. 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 )

22. 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