A little more
1. Low intensity of PAR (minimally admissible) - a range of intensity at which growth of vegetative bodies occurs, but are not formed high-grade generative bodies (bud). Thus photosynthesis has low parameters. For photophilous plants it is intensity in a range 15-30 w/m^2
2. Optimum intensity PAR - a range of intensities at which the maximal accumulation of a biomass in unit of time is observed. Thus The part of a useful part of a crop to sheathe makes 50-70 %. Photosynthesis and growth are well balanced. For photophilous plants it is a range of PAR 150-220 w/m^2
3. Sating intensity of PAR - the maximal intensity of light at which the output of photosynthesis on a plateau of light saturation is reached, ie maximal photosynthesis. Thus, growth inhibition of a stalk and other axial bodies is observed - plants get the undersized form. The part of a useful part of a crop to sheathe is high, but the general biomass collects less, than at optimum intensity as growth is braked (400 PAR w/m^2 and more), requres tripple nutrition feeding