A. M. Shrestha Malla*
Botany Department, Tri-Chandra College, Tribhuvan University, Kathmandu, Nepal

ABSTRACT
Plants contain cyanogenetic glucoside and also the appropriate enzyme which hydrolyses this glucoside and produces HCN. There are different types of plants which contain: the glucoside but not the enzyme; the enzyme but not the glucoside; and neither the glucoside nor the appropriate enzyme. Trifolium repens L. (White clover) is polymorphic for cyanogenesis, with both cyanogenic and acyanogenic plants occurring in nature. The study was done in eight different varieties of Trifolium repens L. collected from different altitudinal zones such as subtropical representing Kirtipur (1245-1300 masl), subtropical to temperate representing Dhunche (1962 -2012masl) and temperate to sub-alpine representing Chandanbari (3400-3500masl). Plants collected from these areas were tested for HCN contents by “Feigl spot test” method. The results showed that highest quantity of HCN was present in WNML, medium in WPML and minimum in LPML variety growing at Kirtipur. Medium quantity of HCN was present in WNML, WPML, WPNML and PNML varieties growing at Dhunche. PML and LPNML varieties have no HCN and were suggested as the best fodder plants for livestock. HCN contents in plants growing in Chandanbari were very low or absent. Similarly, the transplant from Chandanbari to Kirtipur also did not show HCN except a medium amount in PNML variety. The study showed a marked variation in HCN content among the varieties of white clover. It also revealed that the higher amount of HCN was present in white coloured flower than pink coloured flower; HCN content of plant is lesser in colder and higher altitudinal zone and is higher in plant with larger size of the leaves as well as in plants growing in lower moisture and higher phosphorous containing soil.
Keywords: HCN, White clover, Flower colour, Altitude, Moisture, Phosphorous