Effects of stem fraction on the optimization of biomass allocation and maximum photosynthetic capacity

Abstract

Summary 1.A model was developed to examine effects of the stem biomass fraction on the optimal responses of plants to soil nitrogen availability. 2. Our model predicts that the optimal leaf : root ratio and optimal photosynthetic capacity ( P max ) increase with soil N availability. For a given N availability, the optimal leaf : root ratio decreases and the optimal P max increases with increasing stem fraction. As a result, the increase in optimal leaf : root ratio is smaller, and that in optimal P max is greater, in response to increasing N availability when stem fraction is large. 3. To test these predictions we grew two herbs with different stem fractions: Polygonum cuspidatum Sieb. et Zucc. and Chenopodium album L . Showing excellent agreement with the simulation results, the leaf N concentration and leaf : root ratio of the two herbs increased with increasing N availability, and leaf N concentration was larger for C. album with higher stem fraction than P. cuspidatum . 4. The general tendency for plants with larger stem fractions also to have greater leaf N concentrations and P max was demonstrated for a wide range of temperate herbs. This suggests that stem fraction may be a source of variation in P max among plants in the same functional group.

Nitrogen absorption by roots as a cause of interspecific variations in leaf nitrogen concentration and photosynthetic capacity

“…As herbs and deciduous trees have similar leaf life spans, using these plants could minimize the effect on LNC of differences in leaf life span, and highlight the effect of differences in N absorption ability. Second, simulations using the model of Osone & Tateno (2003) were performed to evaluate if each species achieved optimal LNCs. Third, the causal relationship between LNC and N absorption ability proposed by optimal biomass allocation models was verified by manipulating biomass allocation between roots and leaves of Morus bombycis , a deciduous tree, using an inhibitor of gibberellin synthesis.…”

The Biology of Invasive Alien Plants in Canada. 5. Polygonum cuspidatum Sieb. & Zucc. [= Fallopia japonica (Houtt.) Ronse Decr.]

“…Stem and root nitrogen concentrations were strongly correlated with leaf nitrogen content in field populations (Osone and Tateno 2003). In greenhouse grown individuals Osone and Tateno (2003) found specific absorption rates for nitrogen ranging from 1.2 to 27.0 µg N mg -1 d -1 , while Hirose (1984) found values between 0.1 and >20 µg N mg -1 d -1 depending on the growth nutrient solution. Leaf area was inversely related to leaf nitrogen content, while growth rate (net assimilation rate × leaf area) increased sharply followed by a gradual decline (Hirose 1984).…”

“…Net assimilation rate (g m -2 d -1 ) in populations of P. cuspidatum from Japan increased with increasing leaf nitrogen content (g N m -2 ) to a maximum of 6 g m -2 d -1 (Hirose 1984;Osone and Tateno 2003). Stem and root nitrogen concentrations were strongly correlated with leaf nitrogen content in field populations (Osone and Tateno 2003).…”

Fate of 15N-labeled Inorganic Fertilizer in an Upland Soil Applied with Sweet Sorghum Bagasse and N Uptake Efficiency by Komatsuna Plants

“…Azam et al (1992) komatsuna (Table 2) were higher when using a combination of IF and SSB surface application compared to IF application alone. The reason for this higher efficiency when using both IF and SSB surface application is not clear; however, it might result from differences in the balance between N assimilation and C consumption in komatsuna (Osone and Tateno, 2003). Moreover, SSB surface application might affect soil physiochemical and biological attributes in the plant-soil system, such as soil water content, microorganisms, and phosphorus uptake in komatsuna, which consequently have positive effects on komatsuna yield (Othieno, 1973;Barajas-Guzmán et al, 2006).…”