The impact of feeding injury by the Russian wheat aphid, Diuraphis noxia (Mordvilko) (Hemiptera: Aphididae), and bird cherry-oat aphid, Rhopalosiphum padi (L.) (Hemiptera: Aphididae) on susceptible and resistant wheat, Triticum aestivum L., near-isogenic lines 'Tugela' (susceptible), Tugela-Dn1 (antibiotic), Tugela-Dn2 (tolerant), and Tugela-Dn5 (antixenotic) was evaluated by assessing photosyn...

The following three models were combined to predict simultaneously photosynthesis, stomatal conductance, transpiration and leaf temperature of a rose leaf: the biochemical model of photosynthesis of Farquhar, von Caemmerer and Berry (1980, Planta 149: 78-90), the stomatal conductance model of Ball, Woodrow and Berry (In: Biggens J, ed. Progress in photosynthesis research. The Netherlands: Marti...

Hypericin, Cyanobacteria, Photosynthesis, Photodynamic Action The photodynamic action of hypericin on photosynthesis and respiration were monitored in Synechocystis sp PCC 6803 and Synechoccus ATCC 6311 (Anacystis nidulans). An oxygen electrode was used to measure net oxygen evolution or consumption. The amount of hyperi­ cin required to inhibit photosynthesis was quantitively determined. Photo...

BACKGROUND AND AIMS There is a conspicuous increase of poikilohydric organisms (mosses, liverworts and macrolichens) with altitude in the tropics. This study addresses the hypothesis that the lack of bryophytes in the lowlands is due to high-temperature effects on the carbon balance. In particular, it is tested experimentally whether temperature responses of CO(2)-exchange rates would lead to h...

Rates of net photosynthesis were studied in soil-grown corn (Zea mays) and soybean (Glycine max) plants having various leaf water potentials. Soybean was unaffected by desiccation until leaf water potentials were below -11 bars. Rates of photosynthesis in corn were inhibited whenever leaf water potentials dropped below -3.5 bars.The differences in photosynthetic behavior could be attributed sol...

[1] Permafrost melting is occurring in areas of the boreal forest region where large amounts of carbon (C) are stored in organic soils. We measured soil respiration, net CO2 flux, and net CH4 flux during May–September 2003 and March 2004 in a black spruce lowland in interior Alaska to better understand how permafrost thaw in poorly drained landscapes affects land-atmosphere CO2 and CH4 exchange...

ABSTRACT. Net photosynthesis, dark respiration, chlorophyll and carbohydrate content, and leaf and shoot growth in plants of evergreen olive (Olea europaea L.) grown under controlled conditions were measured to assess changes in carbon balance during leaf development of the 6th, 12th, and 16th node (from the base, first flush) through expansion to maturity. Shoot and leaves expanded in a sigmoi...

A push-pull method, previously used in groundwater analyses, was successfully adapted for measuring sulfide turnover rates in situ at different depths in the meromictic Lake Cadagno. In the layer of phototrophic bacteria at about 12 m in depth net sulfide consumption was observed during the day, indicating active bacterial photosynthesis. During the night the sulfide turnover rates were positiv...

Southern pines vary in their response to the loss of leaf area by crown scorch. We hypothesize that they tolerate crown scorch by at least three recovery mechanisms, but the function of these mechanisms is season-dependent. Using sapling longleaf pine as a model and experimental results from central Louisiana, U.S.A., our objective is to present examples recovery from scorch, and discuss how th...