caa a22 4500 477100376 CHVBK 20180405111539.0 cr unu---uuuuu 170330e19961001xx s 000 0 eng 10.1007/BF00208317 doi (NATIONALLICENCE)springer-10.1007/BF00208317 The impact of reduced vacuolar invertase activity on the photosynthetic and carbohydrate metabolism of tomato [Elektronische Daten] [Julie Scholes, Nicholas Bundock, Robin Wilde, Stephen Rolfe] The impact of reduced vacuolar invertase activity on photosynthetic and carbohydrate metabolism was examined in tomato (Solanum lycopersicon L.). The introduction of a co-suppression construct (derived from tomato vacuolar invertase cDNA) produced plants containing a range of vacuolar invertase activities. In the leaves of most transgenic plants from line INV-B, vacuolar invertase activity was below the level of detection, whereas leaves from line INV-A and untransformed wild-type plants showed considerable variation. Apoplasmic invertase activity was not affected by the co-suppression construct. It has been suggested that, in leaves, vacuolar invertase activity regulates sucrose content and its availability for export, such that in plants with high vacuolar invertase activity a futile cycle of sucrose synthesis and degradation takes place. In INV-B plants with no detectable leaf vacuolar invertase activity, sucrose accumulated to much higher levels than in wild-type plants, and hexoses were barely detectable. There was a clear threshold relationship between invertase activity and sucrose content, and a linear relationship with hexose content. From these data the following conclusions can be drawn. (i) In INV-B plants sucrose enters the vacuole where it accumulates as hydrolysis cannot take place. (ii) There was not an excess of vacuolar invertase activity in the vacuole; the rate of sucrose hydrolysis depended upon the concentration of the enzyme. (iii) The rate of import of sucrose into the vacuole is also important in determining the rate of sucrose hydrolysis. The starch content of leaves was not significantly different in any of the plants examined. In tomato plants grown at high irradiance there was no impact of vacuolar invertase activity on the rate of photosynthesis or growth. The impact of the cosuppression construct on root vacuolar invertase activity and carbohydrate metabolism was less marked. Springer-Verlag, 1996 Carbohydrate metabolism nationallicence Invertase (co-suppression construct) nationallicence Photosynthesis nationallicence Lycopersicon nationallicence Vacuole nationallicence CaMV : Cauliflower Mosaic Virus nationallicence WT : wild type nationallicence Scholes Julie Department of Animal and Plant Sciences, University of Sheffield, S102UQ, Sheffield, UK aut Bundock Nicholas Department of Animal and Plant Sciences, University of Sheffield, S102UQ, Sheffield, UK aut Wilde Robin Zeneca Plant Science, Jealott's Hill Research Station, RG42 6ET, Bracknell, Berkshire, UK aut Rolfe Stephen Department of Animal and Plant Sciences, University of Sheffield, S102UQ, Sheffield, UK aut Planta Springer-Verlag 200/2(1996-10-01), 265-272 0032-0935 200:2<265 1996 200 425 https://doi.org/10.1007/BF00208317 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00208317 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Scholes Julie Department of Animal and Plant Sciences, University of Sheffield, S102UQ, Sheffield, UK aut NATIONALLICENCE 700 1- Bundock Nicholas Department of Animal and Plant Sciences, University of Sheffield, S102UQ, Sheffield, UK aut NATIONALLICENCE 700 1- Wilde Robin Zeneca Plant Science, Jealott's Hill Research Station, RG42 6ET, Bracknell, Berkshire, UK aut NATIONALLICENCE 700 1- Rolfe Stephen Department of Animal and Plant Sciences, University of Sheffield, S102UQ, Sheffield, UK aut NATIONALLICENCE 773 0- Planta Springer-Verlag 200/2(1996-10-01), 265-272 0032-0935 200:2<265 1996 200 425 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer