Photosynthesis, photorespiration and plant productivity.

The roles of aqueous vs. atmospheric CO, fixation, photorespiration, dark respiration, and organic release in the primary productivity of Lemna minor L. were investigated experimentally in field populations and in the laboratory. The mean rate of net photosynthesis through the growth season was 2.48 mg C g-l h-l during which an average of 86 % of carbon fixed was from aqueous inorganic carbon. Seasonal variations in photosynthesis correlated principally with light intensity and temperature. Presence of photorcspiration was suggested by early afternoon depressions of photosynthesis, by experimental enhancement and inhibition of photosynthesis with low and high oxygen, respectively, and by enhancement of 1ight:dark respiration ratios with high oxygen. How-ever, under natural conditions L:D ratios were below unity most of the time, and CO, loss in the light was never>4 % of photosynthate fixed per hour. Experimental enhancement of photorespi-ration with oxygen was never as great as the inhibition of photosynthesis at comparable oxygen concentrations. Although plants exhibited a low CO2 compensation point and high light and temperature optima, photosynthesis enzymology and fixation products indicated that C, photo-synthesis was not a significant factor in maintenance of the low photorespiration rates.

Photosynthesis, photorespiration and productivity of wheat and ..

photorespiration and productivity of wheat and ..

Photosynthesis, photorespiration, and plant productivity.

The product of photosynthesis is a , such as the sugar , and oxygen which is released into the atmosphere (Figure 9l-1). All of the sugar produced in the photosynthetic cells of plants and other organisms is derived from the initial chemical combining of carbon dioxide and water with sunlight (Figure 9l-1). This chemical reaction is catalyzed by acting together with other , , , , and molecules. Sugars created in photosynthesis can be later converted by the plant to starch for storage, or it can be combined with other sugar molecules to form specialized carbohydrates, such as . Sugars can also be combined with other such as nitrogen, phosphorus, and sulfur, to build complex molecules such as proteins and nucleic acids.

Photosynthesis, Photorespiration and Productivity of …

The of a is the amount of biomass produced through photosynthesis per unit area and time by plants, the primary producers. Primary productivity is usually expressed in units of energy (e.g., joules m day ) or in units of dry organic matter (e.g., kg m year ). Globally, primary production amounts to 243 billion metric tons of dry plant biomass per year. The total energy by plants in a community through photosynthesis is referred to as (). Because all the energy fixed by the plant is converted into sugar, it is theoretically possible to determine a plant's energy uptake by measuring the amount of sugar produced. A proportion of the energy of gross primary productivity is used by plants in a process called . Respiration provides a plant with the energy needed for various plant physiological and morphological activities. The general equation for respiration is:

05/01/2018 · Photosynthesis, Photorespiration and Productivity of Wheat ..

Manipulating photorespiration to increase plant productivity: ..

The Centre’s goal is to improve the biological process of photosynthesis in the crop plants that humans depend on for food, such as wheat, rice and sorghum.

24/12/2017 · This book is divided into 3 sections

Description :Photosynthesis, Volume II: Development, Carbon Metabolism, and Plant Productivity provides a basic understanding of photosynthesis. This book also explains how to manipulate photosynthesis and improve...

30/11/2017 · Photosynthesis, photorespiration and productivity ..

What Is Photorespiration In Plants? - YouTube

This revolution would be about creating new crop varieties – particularly of wheat, rice and sorghum- with enhanced photosynthetic capacity, and higher productivity. This includes varieties that produce high levels of grain in conditions of lower water, higher temperature and higher levels of carbon dioxide in the atmosphere. Such crops are essential to feeding a growing world population, especially under the challenges of a changing climate.

All of the enzymes needed to do C4 photosynthesis are already in the plant.

Photosynthesis, Photorespiration and Plant Productivity …

Plant researchers have developed an online application that predicts how crop growth is affected by photosynthetic changes at the molecular, cellular or leaf level of plants.

Zelitch, I. (1971) Photosynthesis, photorespiration and plant productivity. Academic Press, 275.


While the photosynthetic process has been intensively studied, improving photosynthesis is a new, and relatively unexplored, frontier in plant science. By improving photosynthesis, the Centre can contribute to a new yield revolution for food crops.