Thesis (MSc)--Stellenbosch University, 1964. / ENGLISH ABSTRACT: The influence of manganese sulphate sprays on the yield
and ripening of fruit of manganese-deficient Vitis vinifera L.
(cv. Pinotage) plants was investigated. Ripening was determined
in terms of changes in concentration of the indivi=
dual and total sugars and organic acids.
Increasing concentrations of manganese sulphate resulted
in significant increases in the manganese content of the
leaves. The higher levels of manganese were associated with
an increase in yield. Ripening, however, was retarded, in
that the percentage sugar of the fruit was decreased and
titrable acid content increased.
The principal sugars present in the fruit were sucrose,
glucose, fructose and xylose. Malic and tartaric acids were
the main organic acid constituents. Glucose and fructose
increased sharply, and sucrose and xylose slightly during
ripening of the fruit, whereas malic and tartaric acid de=
creased. Glucose, fructose, tartaric and malic acid tended
to increase with increasing manganese content.
Sucrose and xylose were not appreciably affected.
An application of 1% manganese sulphate can be recommend-
ยท ed for manganese deficient vineyards, as it results in an
increased yield, in addition to delaying ripening until a
more favourable time for handling. Furthermore, the lowered
sugar content of the fruit may be advantageous for the pro=
duction of dry wines from Pinotage grapes . / AFRIKAANSE OPSOMMING: Die invloed van mangaansulfaatbespuiting op die opbrengs
en vrugrypwording van Vitis vinifera L. cv. Pinotage,
wat aan ernstige mangaantekorte gely het, is ondersoek.
Rypwording is met betrekking tot veranderings in die
konsentrasies van totale en indiwiduele suikers en
sure bepaal.
2. Toenemende konsentrasies Mnso4 (van O.2% tot l.O%) het
n betekenisvolle toename in die mangaangehalte van die
blare (van 3 tot 80 d.p.m.) tot gevolg gehad. Die ver=
hoogde mangaangehalte het gepaard gegaan met n toe=
name in opbrengs, terwyl rypwording vertraag is, deurdat
die suikerpersentasie en die titreerbare suurgehalte ver=
meerder is in vergelyking met die kontroleplante.
3. Die vernaamste suikers in die vrugte was sukrose, glukose,
fruktose en xilose. Glukose en fruktose het vinnig en
sukrose en xilose geleidelik toegeneem met die verloop
van rypwording. In die ryp vrugte was glukose en fruk=
tose oorheersend. Glukose en fruktose was geneig om
toe te neem met toenemende mangaangehalte, terwyl sukrose
en xilose nie beinvloed is nie.
4. Appelsuur en Wynsteensuur was die oorwegende sure in die vrugte. Beide hierdie sure het gedurende rypwording
verminder. Hulle konsentrasies het oor die algemeen
toegeneem namate die mangaankonsentrasie verhoog is.
5. Dit is afgelei dat bespuiting met 1.0% MnS04 aanbeveel
kan word vir wingerde met mangaantekorte, daar dit n
toename in opbrengs, gepaard met 'n vertraging in
rypwording tot gevolg gehad het. So 'n vertraging
mag moontlik in parstyd voordelig wees. Die verlaagde
suikerpersentasie van die vrugte is moontlik
gunstig vir die bereiding van droe wyne, waarvoor
Pinotage hoofsaaklik gebruik word.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/67657 |
| Date | 12 1900 |
| Creators | Barker, Wilma (Wilma Henriette) |
| Contributors | De Bruyn, J. A., Stellenbosch University. Faculty of AgriSciences. Dept. of Viticulture and Oenology and Institute for Wine Biotechnology . |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | af_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | [iv], 55 p. : ill. |
| Rights | Stellenbosch University |
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