Chlorella pyrenoidosa was grown in a continuous-flow chemostat under nitrogen-limited conditions. The population density tended to oscillate very significantly. Net specific growth rate was only approximately a hyperbolic function of nitrate concentration in the chemostat. The best estimate of the half-saturation constant for nitrate is 6 mug of nitrogen per liter and it is unlikely that the va...

PB 103 The six chapters (Chapters 10-15) in Part III consider the current and future carbon balance of terrestrial and aquatic ecosystems in North America. Although the amount of carbon exchanged between these ecosystems and the atmosphere each year through photosynthesis and plant and microbial respiration is large, the net balance for all of the ecosystems combined is currently a net sink of ...

When assessing net ecosystem exchange (NEE) and net ecosystem carbon balance (NECB), respiration is generally assumed to be the only significant loss of carbon to the atmosphere. However, carbon is also emitted from ecosystems in the form of biogenic volatile organic compounds (BVOCs). Here we consider the magnitude of systematic difference caused by omitting this additional carbon loss from th...

Many studies examine how body size mediates energy use, but few investigate how size simultaneously regulates energy acquisition. Furthermore, rarely energy fluxes are examined while accounting for the role of biotic and abiotic factors in which they are nested. These limitations contribute to an incomplete understanding of how size affects the transfer of energy through individuals, population...

The interaction of photosynthesis and respiration has been studied in vivo under conditions of limited water supply and after consecutive rewatering. The role of the alternative (v(alt)) and cytochrome (v(cyt)) pathways on drought stress-induced suppression of photosynthesis and during photosynthetic recovery was examined in the Nicotiana sylvestris wild type (WT) and the complex I-deficient CM...

Inhibition of photosynthesis by ultraviolet-A radiation (UV-A, 315-380 nanometers) was examined in three marine angiosperms: Halophila engelmannii Aschers, Halodule wrightii Aschers, and Syringodium filiforme Kütz. Sensitivity to UV-A and photosensitization to UV-A by photosynthetically active radiation (PAR, 380-700 nanometers) were characterized.Net photosynthesis by Halodule and Syringodium ...

The effect of cadmium (Cd) on growth, photosynthesis, biochemical attributes and antioxidant enzymes activities in tomato (Solanum lycopersicum L.) seedlings was studied and the role of kinetin (KN) to ameliorate Cd toxicity was examined. Tomato seedlings were subjected to two doses of Cd viz. 3 and 9 mg Cd kgP P sand. Cadmium at both the doses significantly declined the growth and photosynthes...

change system to measure the net exchange of CO2 at the surfaces of three shady feather moss and three exposed sphagnum moss sites in a black spruce forest during 35 days at the end of the 1995 growing season. Midday gross photosynthesis was 0.5 to 1.0 μmol m s by feather moss and 0.5 to 2.5 μmol m s by sphagnum moss. Photosynthesis by sphagnum moss was reduced by approximately 70% at 0 °C, and...

Mechanical stimulation of trigger hairs on the adaxial surface of the trap of Dionaea muscipula leads to the generation of action potentials and to rapid leaf movement. After rapid closure secures the prey, the struggle against the trigger hairs results in generation of further action potentials which inhibit photosynthesis. A detailed analysis of chlorophyll a fluorescence kinetics and gas exc...

Photoprotection mechanisms of rice plants were studied when its seedlings were subjected to the combined stress of water and high light. The imposition of water stress, induced by PEG 6000 which was applied to roots, resulted in substantial inhibition of stomatal conductance and net photosynthesis under all irradiance treatments. Under high light stress, the rapid decline of photosynthesis with...