Compensating Effects to Growth of Changes in Dry Matter Allocation in Response to Variation in Photosynthetic Characteristics Induced by Photoperiod, Light and Nitrogen
Australian Journal of Plant Physiology
15(2) 287 - 298
High N-nutrition, high light and long photoperiod increased photosynthetic capacity (Amax) per leaf area of Raphanus sativus × raphanistrum. The effect of Amax on growth was enhanced by an increased fraction of dry matter partitioned into the shoot, resulting in a larger canopy. Low N-nutrition, low light and a short photoperiod reversed these responses. At intermediate combinations, such as low light and long photoperiod or high light and short photoperiod, Amax and the actual net photosynthesis per leaf area (A) neither correlated with the carbon uptake rate of the canopy as a whole nor with whole plant growth. A compensatory effect to growth of changes in dry matter partitioning in response to variation in photosynthetic characteristics induced by light and N-nutrition is discussed in terms of two competitive feedbacks. For growth a long photoperiod compensated for low light or low N-nutrition. The results indicate that extrapolations from rates to gains are only valid under defined environmental conditions, especially when different photoperiods and effects on leaf ontogeny are involved.
© CSIRO 1988