OLM 8.3.  Relationship of protoplasm/cell wall ratio and photosynthetic capacity


The two extreme ends of the leaf economy spectrum (Table 8.1, p. 148) are occupied by metabolically very efficient plants which are poorly defended against herbivores and mechanical damage on the one hand, and well defended but very inefficient ones on the other. The defence is often mechanical, in which case the trade-off between growth and defence is due to the constraint that cytoplasm and cell wall can increase only at each other’s expense within a certain volume. Below we show (following Shipley et al. 2006) that increasing cell wall proportion while keeping all other parameters constant, photosynthetic capacity (i.e., the quantity of assimilates produced by a unit biomass of leaves) decreases.   


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