Shoot development of three physiological ages of gongronema latifolia as influenced by some of their chemical composition

Abstract

Two experiments (one in the farm the other in the laboratory) were conducted at the University of Nigeria, Nsukka, between February and April 2006 to determine the shooting potentials of three physiological ages (hardwood, semi-hardwood and softwood) of the stem cuttings of G. latifolia in relation to their chemical composition. The results showed that opening of first buds and first shooting occurred in softwood cuttings in 3 and 6 days, respectively. Softwood recorded the least days to buds and shoots initiation than either hardwood or semi-hardwood. Softwood cuttings on the average had 61% shooting of cuttings by the second week of planting and this was significantly (p<0.05) higher than values of semi-hardwood (21%) and hardwood (41%) during the study period. However, hardwood cuttings had vine lengths of 2.90cm by the second week of planting compared with 1.06cm recorded for softwood. Equally, softwood cuttings had 16.14 % protein, which was significantly (p<0.05) higher than either semihardwood or hardwood throughout the study period. The higher level of protein in the softwood and significant positive correlation between softwood and percentage shooting (r=0.43: n=24) at two weeks after planting support earlier development of shoot and opening of leaves in softwood cuttings. On the other hand, low carbohydrate level in the softwood cuttings could not sustain the initial rate of shoot development and growth. Hardwood cuttings eventually had significantly (p<0.05) higher shooting rate at the end of eight weeks. The positive and significant correlation (r=0.67:n=24) between carbohydrate level of parent cuttings and vine length suggest that carbohydrate has high influence on growth of vines and leaves. Also, the significant longer vines observed in the hardwood cuttings from second week after planting even though softwood cuttings started earlier showed the importance of carbohydrate level on growth of vines. The three physiological age groups of cuttings used in this study had showed varying levels of chemical composition. The internal chemical properties of the cuttings also had varying degrees of influence on the development of vines/shoots as well as growth potentials.