Suggested Amendments in Growth Analysis and Potentiality Assessment in Relation to Light

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Abstract
It is suggested that dry-weight accumulation, productivity of unit leaf area and leaf-growth be measured by the available light energy instead of time scale. Potential photosynthesis (ap), as calculated by de Wit, is considered to be the most suitable form. The implementation of the new technique is discussed and the characteristics thereby obtained denoted as Photosynthetic Productivity (PP), Leaf Area Efficiency (LEF), and Leaf Area Extension Rate (LEX) respectively. The above technique was adopted by the author in some experiments and the results conform with the expectation. The critical leaf area varies with the angle of sun above the horizon. The Photosynthetic Productivity lies between the limits 0–0.95. It increases with increasing leaf area until its maximum, while LEF decreases from 0.95 downwards. LEX is greater at low light values, especially with higher temperatures. It is suggested that the critical leaf area index (Le), by which the highest productivity could be obtained if it could be maintained unaltered, should be distinguished from the leaf area index which provides the most favourable PP during any undisturbed growing period, and the latter may be called optimal leaf area index (Lo). A procedure based on growth analysis by light scale is described, by which more appropriate evaluation and comparison of grass species and varieties may be achieved.