The by-products produced in the metabolism of protoplasm are called waste products. These waste materials accumulate in leaves, fruit bark, stem bark, mother cells and tissues. Different types of waste materials are-
(i) Resin: The resinous substance present in the resin ducts of plants like pine, Arocaria etc. is called resin. Resin is used to smooth the strings of sitar and violin.
(ii) Tannin: Tannins are present in the fruit and seeds of tamarind and gab plants. Tannins are used to tan leather, make dyes and inks.
(iii) Gum : Plants like Jiga, Sajina, Acacia etc. contain gum or gum. It is used as glue.
(iv) Organic Acids: Malic acid in cherry and tomato, citric acid in pineapple, grape and lemon, oxalic acid in amrule, tartaric acid in tamarind, date and grape, glycolic acid in beet and raw grapes, lactic acid in opium and cucumber, tannic acid in tea. , olive oil contains oleic acid and apricot contains ascorbic acid.
(v) Latex : Stems, leaves, flowers and fruits of plants like banyan, fig, ash^thth, akanda, karbi, akanda, safeda, jackfruit etc. contain tarukshir or latex.
(vi) Terpenoids: Tulsi leaves, mint leaves, Pinus cells etc. contain terpenoids.
(vii) Alkaloids : Nicotine in tobacco, daturine in dhutura, caffeine in coffee, opium in opium, serpentine in sarpagandha, quinine in cinchona etc.
(viii) Volatile oil: Flowers, fruits and leaves of plants like lemon, tulsi, kamini, raktadrona, svetadrona, eucalyptus etc. contain volatile oil.
(ix) Mineral crystals: Mineral crystals are of two types. Cystoliths and raphides. Grapefruit-like calcium carbonate is called a cystolith. Cystoliths are present in the leaves of plants like banyan, ash, fig, rubber etc. Needle-like calcium oxalate is called raphide. Plants like Manakchu, Olakchu, Mukhikchu etc. have raphides on their stems and leaves.