Effects of total solar radiation and temperature on vegetative growth in the East of Scotland.
Effects of total solar radiation and temperature on the early vegetative growth of Helianthus annuus cv. Polestar and Phaseolus vulgaris cv. Canadian Wonder were investigated in the east of Scotland in a series of experiments carried out at weekly intervals between May and Oct. in 1969 and 1970. By harvesting paired sets of plants at the beginning and end of each weekly interval, variations in NAR, final LAR and RGR could be related to radiation, temperature and initial LAR, a parameter which reflects time of season differences in development and morphology. Multiple linear regressions linking these dependent and independent variables were calculated for each year and were compared between years. Differences in regressions between years were not significant and in both species NAR was positively dependent on radiation and temperature, final LAR on initial LAR, and RGR on radiation, temperature and initial LAR. Throughout the season the RGR of H. annuus was higher than that of P. vulgaris, due both to a higher NAR and initial LAR. Results are compared with other investigations in England and Scotland and their bearing on the growth of crops in Scotland is discussed.