Physiological factors affecting the development of the first influorescence in the glasshouse tomato (Lycopersicon Esculentum, Mill.)
Physiological factors affecting the development of the first influorescence in the glasshouse tomato (Lycopersicon Esculentum, Mill.)
The importance of carbohydrate nutrition in determining the rate and extent of inflorescence development in the glasshouse-grown tomato was investigated. To assess the extent of floral development in each inflorescence, a 'flower development index' (FDI) was devised, ranging from 0 : complete abortion of all flowers, to 100 successful anthesis of every flower. Lighting, spacing and defoliation treatments were applied to the plants soon after buds visible, and the effects of these treatments on the FDI and on the carbohydrate composition of the first inflorescence were determined. Reducing the light energy available (by altering intensity or plant spacing) and the source leaf area (by defoliation) led to a reduction in the reducing sugar and starch concentrations in the inflorescences and a correlated reduction in FDI. A corresponding decrease in the reducing sugar/sucrose ratio was also observed. A comprehensive picture was constructed of the interrelationships between source leaves and the competing sinks for assimilate at the 12-leaf stage, using 140 labelled sucrose supplied to leaves 1-10 inclusive. Only leaf 3 consistently supplied the first inflorescence in preference to other sinks at this growth stage. Reductions in light intensity and day length, leading to complete flower abortion, drastically reduced the import of assimilate by the inflorescence and altered the partitioning of labelled sucrose between the ethanol-soluble and insoluble fractions. It was not clear, from these studies alone, whether this reduced import was causally related to abortion or occurred because abortion had already irreversibly reduced assimilate demand. The capacity of inflorescence tissues to hydrolyse sucrose (termed 'hydrolase' activity and largely attributed to invertase) was assayed over a range of FDIs. The 'hydrolase' activity in the whole inflorescence decreased as the FDI decreased. In inflorescences developing normally, between the times of buds visible and the start of fruit swelling, activity rose to a peak shortly before anthesis. It is considered possible that pollen development might be important in determining the 'hydrolase' activity of the flower, and hence its sink activity. In aborting inflorescences, a low level of activity was maintained, possibly indicating a causal relationship between 'hydrolase' activity and abortion. The role that plant growth substances might play in inflorescence development is also briefly discussed.
University of Southampton
Russell, Christine Rosemary
1980
Russell, Christine Rosemary
Russell, Christine Rosemary
(1980)
Physiological factors affecting the development of the first influorescence in the glasshouse tomato (Lycopersicon Esculentum, Mill.).
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The importance of carbohydrate nutrition in determining the rate and extent of inflorescence development in the glasshouse-grown tomato was investigated. To assess the extent of floral development in each inflorescence, a 'flower development index' (FDI) was devised, ranging from 0 : complete abortion of all flowers, to 100 successful anthesis of every flower. Lighting, spacing and defoliation treatments were applied to the plants soon after buds visible, and the effects of these treatments on the FDI and on the carbohydrate composition of the first inflorescence were determined. Reducing the light energy available (by altering intensity or plant spacing) and the source leaf area (by defoliation) led to a reduction in the reducing sugar and starch concentrations in the inflorescences and a correlated reduction in FDI. A corresponding decrease in the reducing sugar/sucrose ratio was also observed. A comprehensive picture was constructed of the interrelationships between source leaves and the competing sinks for assimilate at the 12-leaf stage, using 140 labelled sucrose supplied to leaves 1-10 inclusive. Only leaf 3 consistently supplied the first inflorescence in preference to other sinks at this growth stage. Reductions in light intensity and day length, leading to complete flower abortion, drastically reduced the import of assimilate by the inflorescence and altered the partitioning of labelled sucrose between the ethanol-soluble and insoluble fractions. It was not clear, from these studies alone, whether this reduced import was causally related to abortion or occurred because abortion had already irreversibly reduced assimilate demand. The capacity of inflorescence tissues to hydrolyse sucrose (termed 'hydrolase' activity and largely attributed to invertase) was assayed over a range of FDIs. The 'hydrolase' activity in the whole inflorescence decreased as the FDI decreased. In inflorescences developing normally, between the times of buds visible and the start of fruit swelling, activity rose to a peak shortly before anthesis. It is considered possible that pollen development might be important in determining the 'hydrolase' activity of the flower, and hence its sink activity. In aborting inflorescences, a low level of activity was maintained, possibly indicating a causal relationship between 'hydrolase' activity and abortion. The role that plant growth substances might play in inflorescence development is also briefly discussed.
This record has no associated files available for download.
More information
Published date: 1980
Identifiers
Local EPrints ID: 463337
URI: http://eprints.soton.ac.uk/id/eprint/463337
PURE UUID: 1c400ced-0c26-491d-aa09-76346a2caf24
Catalogue record
Date deposited: 04 Jul 2022 20:50
Last modified: 04 Jul 2022 20:50
Export record
Contributors
Author:
Christine Rosemary Russell
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics