As early growth is exponential it was measured as the pseudo-first-order rate coefficient,k1prime;. The growth coefficient is independent of the method of measurement, so different values derived from different measurements such as dry weight, fresh weight, chlorophyll content, and area reflected somewhat different aspects of growth in a given organ. At low light intensityk1prime; was highest for lamina dry weight and lowest for root dry weight, and at high light intensity, highest and lowestk1prime;.were obtained for "stem" dry weight and lamina area, respectively. The differences in rate coefficients between organs were less than 10 of their values at high light intensity. The rectangular hyperbolic fit of the dependence ofk1prime; on light intensity was used to compute a maximum value (kmL) independent of light intensity. AkmLof 0.34 per day was obtained for plants of Marquis wheat grown at 25 deg;C with Hoagland's solution in Went's medium under controlled environment, and the highest value, 0.37, was achieved by dry weight of "stems." A complex form parameter was also computed, and it included a function of the efficiency of light use for growth, which was highest for leaf area and lowest for root dry weight. Measurements on complete morphological entities such as whole organs are best interpreted. Growth kinetics and its relationship to "growth analysis" were discussed in distinct favor of the former approach. The growth coefficient as the relative growth rate has been abused and that term should be dropped. The prospects of kinetic or primary analysis as the standard quantitative method are great, as initially envisaged by V. H. Blackman half a century ago.
展开▼
