University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Master / Diploma Thesis:
Jedi Joy Mahilum
(2014):
Effects of Sink-Source Manipulation of Grapevine Plants on the Activity of Carbohydrate Enzymes in leaves.
Master / Diploma Thesis - Abteilung Wein- und Obstbau,
BOKU-Universität für Bodenkultur,
pp 48.
UB BOKU
obvsg
FullText
- Abstract:
- Sugar content is an important determining factor of grape berry quality. Among the sugars present in grapevines are sucrose, glucose and fructose. Sucrose is synthesized in the source organs (leaves) and transported to siink organs which is further metabolised into simple sugars such as fructose and glucose that can be used in the carbon skeleton of the plant during its growth and development or stored in organs for reserve as starch. This degradation of sugars is catalysed with enzymes namely invertases and sucrose synthase. Enzymatic activities are regulated by genes and are also affected by environmental factors or stress. The canopy of the plant plays a big role in the photosynthetic activity of the plant which is the driving mechanism for its growth rate. Canopy management is one of the cultural management practices that affect physiological aspects of the plant by improved micro-climatic conditions and manipulating sink-source relationships. This experiment aimed at investigating the fluctuations in sugars present in grapevine tissues as well as the changes in enzymatic activities involved in sugar metabolism through canopy management at groat-sized (BBCH 73) and ripening (BBCH 89) stage. Results showed that defoliation of leaves and shoot increased starch content with decreasing amount of leaf canopy at an early stage of development, 3 days after removal. But at ripening stage, trend of starch content in leaves decreases with decreasing canopy. Ont he other hand, glucose and fructose concentrations have no significant difference between treatments as affected by leaf defoliation. Enzymatic activities in the leaves also did not show evident differences among treatments. the result suggest that high starch content in the leaves entails low enzymatic activities and conversion of sucrose into glucose and fructose despite the difference in amount of canopy (shoot and leaves).
- Beurteilende(r): Forneck Astrid
- 1.Mitwirkender: Griesser Michaela