KARACHI, March 3: The thorny cactus that loves arid zones and lives on frugality has been grown for the first time in Pakistan through the use of hydroponic method — growing a plant in water container without the help of soil.

Cacto form a separate family, bears no leaves — very small or insignificant ones), frequently developing highly distended juicy stems in strange shapes, which beside fulfilling the general purpose of serving as ducts or reservoirs for the storage of water and nourishment, also carry out the physiological process of the missing leaves. They are usually heavily armed with spines and barbed hairs, live for years, overcoming the perils of drought and lack of food, that has earned them the nickname of the monks of the deserts.

Each plant has small roots for anchorage and to absorb nourishment from the soil where other plants will hardly survive. Heavy rain upsets their life-cycle and more often than not, kills many. Growing them through the medium of hydroponics has, therefore, not been tried because of the fear that the excess of water will drown the water-carrying channels; the plant will not be able to eliminate the excess of water by surface evaporation by the outer surface for keeping just enough to survive.

They are propagated by seeds and also by grafting a costly or difficult plant on a cheaper type of cactus that will serve as the mother-plant, will supply nourishment and water through its own system. Once the grafted plant joins the mother plant, it survives on mother plant’s resources.

An amateur grower, Hameed Rizvi, implanted one of the cactus on a common cactus that did not accept it well. When the bay-plant fell off the mother-plant, he out of curiosity, used the hydroponic method to see if it will work, it did, but instead of growing rudimentary roots, it grew long slender roots into the medium — ordinary tap water. Two plants grown by this method were displayed in a recent meeting, where it surprised everyone.

Several explanations were expounded for this queer adaptation of a plant that, by the usual methods of growth, should have died, when its lower water and food absorbing parts were dipped in water, that would seep up through osmosis and capillary action. The puzzling part was the absence of any artificial food added for the plant to grow.

One of the plausible explanations given by Dr Ehsanullah — one of the well-known experts on how body- fluids and electrolytes work in human bodies — was the most acceptable, that Karachi’s tap water was highly polluted, contained several-water soluble salts that sustained the cacti in an alien medium and provided it with basic nourishment that its system could make use of. It opened a new dimension in cactus behaviour in so far that they were far more adaptable than was believed.

The reason for growing roots several times thicker and numerous in water was that since it contained far low nourishment, it grew more roots to draw enough nourishment from the tap water that had less diminished nourishment which diminished everyday from the absorption of the salts in its. It had added a new chapter to the allusive physiology of the plant, that was, so far believed to live in a restricted shapers of discipline of survival. —Dr A.A. Quraishy