Manipulation Of Photosynthesis Research Articles

Manipulation of Photosynthesis in Grape (Vitis vinifera) CV. ‘Flame’ by the Application of Two Sucrose Analogs

The translocation of photosynthates from the leaves is important for the accumulation of sugars in grape berries. Two sucrose analogs were applied at post-veraison to determine their effects on leaf photosynthesis. It is hypothesized that the signal of sugar accumulation in leaves will bring a reduction in photosynthesis and an increase in the photosynthate translocation rate to the berries. The experiment was conducted in a commercial Vitis vinifera ‘Flame’ vineyard. The sucrose analogs used were palatinose and turanose at 5 mM. For each treatment, five fully expanded leaves from five different vines were sprayed until run-off. Control leaves were treated with distilled water. Net photosynthesis rate (Pn), stomatal conductance (gs), Photosynthetically Active Radiation (PAR) and leaf temperature (Lt) were measured at 0, 10, 20, 30, 60 and 90 min after the treatment with a LICOR-6200 portable photosynthesis system. Statistical analysis was made by variance analysis based on a randomized complete block design and means separated using the Student-Newman-Keuls test with a confidence level of 0.05. The application of turanose did not affect Pn whereas palatinose reduced the Pn one hour after application. At this point, not statistical differences were found in gs and PAR. It was concluded that the application of palatinose can reduce the net photosynthesis which suggests that it is possible to manipulate photosynthesis by the utilization of sucrose analogs which maybe also increases the translocation of photosynthates from grape leaves to grape berries.

Increasing photosynthetic carbon assimilation in C3 plants to improve crop yield: current and future strategies.

The realization that crop yields are reaching a plateau, while population increases continue at pace, has placed manipulation of photosynthesis in a central position to achieve increases in yield. Increasing flux through the C3 cycle will be a major focus of this effort. Through application of new

Differential Gene Expression Profiles of the Mitochondrial Respiratory Components in Illuminated Arabidopsis Leaves

Plant mitochondria have multiple energy-dissipating components in the respiratory chain. It is known that these components are induced under several stress conditions. Here we examined whether the gene expression pattern and its regulatory mechanism under high light (HL) conditions are different among the respiratory components in Arabidopsis leaves. Alternative oxidase (AOX) gene expression (AOX1a and AOX1c) and amount of protein were elevated after exposure to HL. In addition to AOX, the expression of other respiratory genes, including NDA1, NDB2, NDC1, UCP1, UCP5, COX6b and CI76, was also induced by HL. NDB2 was co-expressed with AOX1a, but other HL-induced genes showed a distinct expression pattern. Manipulation of photosynthesis or respiration using several chemicals revealed that while the expression of AOX1a and NDB2 was mainly induced by inhibition of the respiratory chain, NDA1 expression was affected by photosynthesis-related reactive oxygen species. The expression of AOX1c, NDC1, COX6b and CI76 was not induced by these manipulations. When plants were exposed to HL under a high CO(2) environment, the expression of several respiratory genes was more strongly induced, suggesting that modulations of cellular carbon status by elevated photosynthesis are involved in respiratory gene expression. Based on these results, we propose a mechanistic model of respiratory gene expression in illuminated leaves.

Botany: Manipulation of photosynthesis

Botany: Manipulation of photosynthesis