References
- Abe , L.O. and Imbamba , S.K. 1977 . Levels of vitamins A and C in some Kenyan vegetable plants . E. Afr. Agric. For. J. , 42 : 316 – 321 .
- AOAC . 1984 . Official Methods of Analysis. , 13 th edition , Washington, D.C. : Association of Official Analytical Chemists .
- Barker , A.V. , Maynard , D.N. and Mills , H.A. 1974 . Variation in nitrate accumulation among spinach grown cultivars . J. Am. Soc. Hort. Sci. , 99 : 132 – 134 .
- Black , C.A. 1968 . Soil plant relationships , New York and London : John Wiley and son Inc. .
- Buck , W.B. , Preston , K.S. , Abel , M. and Marshall , V.L. 1966 . Perirenal edema in swine. A disease caused by common weeds . J. Am. Vet. Med. Assoc. , 148 : 1525 – 1531 .
- Burns , R.E. 1963 . Methods of tannin analysis for forage crop evaluation . Georgia Agric Exp. Tech. Bull. , 32 : 1 – 14 .
- Carlsson , R. Research in food science and nutrition . Proc. Vlth International Congress of Food Science and Technology . Dublin. Nitrate and oxalate contents in leaves and stems of wild and cultivated leafy vegetables , Vol. I ,
- Cataldo , D.A. , Haroon , M. , Shrader , L.E. and Youngs , V.L. 1975 . Rapid colorimetic determination of nitrate in plant tissue by nitration of salicylic acid . Comm. Soil Sci. Plant Anal. , 6 : 71 – 80 .
- Chweya , J.A. 1984 . Yield and quality of kale as affected by nitrogen side dressing, spacing and supplementary irrigation . Acta Hortic. , 163 : 295 – 301 .
- Chweya , J.A. 1985 . Identification and nutritional importance of indigenous green leaf vegetables in Kenya . Acta Hortic. , 173 : 99 – 108 .
- Chweya , J.A. 1986 . Nitrate accumulation in kale (Brassica oleraceae var. acephala D.C.) as affected by nitrogen top‐dressing . HortScience , 21 : 272 – 274 .
- Epenhuijsen , C.W. Van . 1974 . Growing native vegetables in Nigeria , Rome : FAO .
- FAO . 1988 . Unexploited traditional food plants: An important source for improving nutrition and food security Rome
- FAO . 1989 . Edible plants of Uganda: The value of wild and cultivated plants as food , Food and nutrition Paper 42/1 Edited by: Goode , P.M. Rome
- Fritz , D. and Habben , J. 1973 . Influence of fertilization on the quality of vegetables particularly for processing . Acta Hortic. , 29 : 349 – 360 .
- Gomez , M.I. 1981 . Carotene content of some green leaf vegetables of Kenya and effects of dehydration and storage on the carotene retention . J. Plant food. , 3 : 231 – 244 .
- Gomez , M.I. 1982 . Sources of vitamin C in the Kenya diet and their stability to cooking and processing . Ecol. Food Nutri. , 12 : 179 – 184 .
- Habben , J. 1973 . Quality constituents of carrot as influenced by nitrogen and potassium fertilization . Acta Hortic. , 29 : 295 – 304 .
- Hill , R.M. and Rawate , P.D. 1982 . Plant mineral nutrition , London : The English University Press .
- Ifon , E.T. and Bassir , O. 1980 . The nutritive value of some Nigerian leafy vegetables: Part 2. The distribution of protein, carbohydrates, crude fat, crude fibre and ash . Food Chem. , 5 : 231 – 235 .
- Imbamba , S.K. 1973 . Leaf protein content in some Kenyan vegetables . E. Afr. Agri. For. J. , 38 : 246 – 256 .
- Kunsch , V. , Scharer , H. and Temperli , A. Nitrate content as quality factor in leafy vegetable crops In. Research in food science and nutrition . Proc. of the VIth International Congress of Food Science and Technology . Dublin. Vol. I ,
- Lee , D.H.K. 1970 . Nitrate, nitrite and methaemoglobinemia . Environ. Res. , 3 : 484 – 511 .
- Marshall , V.L. , Buck , W.B. and Bell , G.L. 1967 . Pigweed (Amaranthus retroflexus): An oxalate containing plant . Am. J. Vet. Res. , 28 : 888
- Mathooko , F.M. and Imungi , J.K. 1995 . Ascorbic acid changes in three indigenous Kenyan leafy vegetables during traditional cooking . Ecol. Food Nutri. , 32 : 239 – 245 .
- Mwanjuma , L.B.S. 1982 . “ Survey of production and utilization of fruits and vegetables of the Machakos District and their nutritional evaluation with emphasis on indigenous species ” . Kenya : Univ. of Nairobi . M.Sc. Thesis
- Mengel , K. 1979 . Influence of exogenous factors on the quality and chemical composition of vegetables . Acta Hortic. , 93 : 133 – 151 .
- Oke , O.L. 1968 . Chemical changes in some Nigerian vegetables during growth . Exp. Agric. , 4 : 345 – 349 .
- Pingle , U. and Ramasastri , B.V. 1978a . Calcium absorption from oxalates rich green leaves . Br. J. Nutri. , 39 : 119 – 125 .
- Pingle , U. and Ramasastri , B.V. 1978b . The effect of water soluble oxalates in Amaranthus spp. leaves on the absorption of milk calcium . Br. J. Nutri. , 40 : 591 – 594 .
- Robinson , C.H. 1973 . Fundamentals of normal nutrition , New York : Macmillan Publishing Company Inc. .
- Simons , C. 1966 . Nitrate poisoning from spinach . The Lancet. , 1 : 872
- Singleton , V.L. 1981 . Naturally occurring food toxicants: Phenolic substances of plant origin common in foods . Adv. Food Res. , 27 : 149 – 221 .
- Sorensen , J.N. 1984 . Dietary fibre and ascorbic acid in white cabbage as affected by fertilization . Acta Hortic. , 163 : 221 – 230 .
- Sreeramalu , N. 1982 . Chemical composition of some green leafy vegetables grown in Tanzania . J. Plant Food. , 4 : 139 – 141 .
- Tisdale , S.L. , Nelson , W.L. and Becton , J.D. 1985 . Soil fertility and fertilizers , New York : Collier Macmillan Publishing Company Inc. .