and arabinose are tasteless; mannose and galactose are toxic to bees; where,
gentiobiose and cellobiose and repellent to bees.
The nectar composition can vary greatly depending on plant species and environmental conditions [38], as well as on floral sexual phases [70], and flower
position within inflorescences [71]. According to [72], between-plant variability of
nectar sugar composition can be due to a casual selection of flowers of different ages,
because in some cases, sucrose breakdown in nectar can be related to flower age. But
this cannot be applied on the results of the recent investigation reported on sour
cherry [64] were the flowers were in the same phenophase code [65], BBCH scale
[73]. On the other hand, some authors considered nectar sugar composition as it is
conservative taxonomic character [26, 74].
So far, sugar composition of sour cherry nectar was only explored by the two
research groups. One research group was investigating sour cherry cultivars in
Újfehértó, in the eastern Hungary in the period 1997–2000 [41, 46, 47]. The following
sour cherry cultivars were examined: “Újfehértói fürtös,” “Pándy 48,” “Érdi
jubileum,” “Meteor USA,” “Montmorency,” “Debreceni bőtermő,” “Nefris,” “Sárándi
S/Gy,” “Korai pipacs,” “Mej Djuk,” “Kőrösi korai,” “Érdi nagygyümölcsű,”
“Kántorjánosi 3,” “Oblacsinszka,” “Érdi bőtermő,” “Cigány 404.” Three sugar components (glucose, fructose, and sucrose) were determined by thin layer chromatography and quantitative evaluation was carried out by densitometry (CAMAG TLC
Scanner II). The cultivars “Újfehértói fürtös,” “Pándy 48,” “Érdi jubileum,” and
“Érdi bőtermő” yielded nectar with high sucrose content in each season, even under
varying climatic conditions, and are valued from an apicultural point of view [46].
Subsequently, in order to determine the floral insect attraction, the floral secretory
product of the two cultivars, an autofertile cultivar (“:Újfehértói fürtös”) and an autosterile
cultivar (“Pándy 48”) were studied [41]. The nectar of both studied cultivars contained all
three major sugar components: sucrose, glucose, and fructose. The nectar sugar composition of “Újfehértói fürtös” varied to a great extent according to the seasons. The
phenomenon was explained by the great fluctuation in air temperatures, which influenced
the sugar production of the cultivar to a great degree. “Pándy 48” yielded nectar with
quite stable concentration and composition in the studied four seasons.
The other research group studied nectar of the most planted sour cherry cultivar
in Serbian orchards, “Oblačinska” sour cherry, an autochthonous cultivar [64].
Investigation included 16 nectar samples of “Oblačinska” sour cherry clones. Both
the content of sugars and sugar alcohols were studied using high performance anion
exchange chromatography with pulsed amperometric detection (HPAEC/PAD).
Carbohydrates were separated on a CarboPac® PA10 pellicular anion-exchange
column. Total of 14 sugars and 6 sugar alcohols were determined, showing great
variability in carbohydrate profiles among studied genotypes. Nectars from several
sour cherry clones stood out based on the notably different concentrations of the
individual sugars and sugar alcohols. Such an unequaled nectar composition was
related to the assumption that Oblačinska sour cherry is not a cultivar but mixture of
many different genotypes.
As reported in [41], during 4-year study sucrose level in cultivars „Újfehértói
fürtös “and „Pándy 48 “ranged from 18–59 mg/mL and from 27–59 mg/mL,
762
M. F. Akšić et al.
gentiobiose and cellobiose and repellent to bees.
The nectar composition can vary greatly depending on plant species and environmental conditions [38], as well as on floral sexual phases [70], and flower
position within inflorescences [71]. According to [72], between-plant variability of
nectar sugar composition can be due to a casual selection of flowers of different ages,
because in some cases, sucrose breakdown in nectar can be related to flower age. But
this cannot be applied on the results of the recent investigation reported on sour
cherry [64] were the flowers were in the same phenophase code [65], BBCH scale
[73]. On the other hand, some authors considered nectar sugar composition as it is
conservative taxonomic character [26, 74].
So far, sugar composition of sour cherry nectar was only explored by the two
research groups. One research group was investigating sour cherry cultivars in
Újfehértó, in the eastern Hungary in the period 1997–2000 [41, 46, 47]. The following
sour cherry cultivars were examined: “Újfehértói fürtös,” “Pándy 48,” “Érdi
jubileum,” “Meteor USA,” “Montmorency,” “Debreceni bőtermő,” “Nefris,” “Sárándi
S/Gy,” “Korai pipacs,” “Mej Djuk,” “Kőrösi korai,” “Érdi nagygyümölcsű,”
“Kántorjánosi 3,” “Oblacsinszka,” “Érdi bőtermő,” “Cigány 404.” Three sugar components (glucose, fructose, and sucrose) were determined by thin layer chromatography and quantitative evaluation was carried out by densitometry (CAMAG TLC
Scanner II). The cultivars “Újfehértói fürtös,” “Pándy 48,” “Érdi jubileum,” and
“Érdi bőtermő” yielded nectar with high sucrose content in each season, even under
varying climatic conditions, and are valued from an apicultural point of view [46].
Subsequently, in order to determine the floral insect attraction, the floral secretory
product of the two cultivars, an autofertile cultivar (“:Újfehértói fürtös”) and an autosterile
cultivar (“Pándy 48”) were studied [41]. The nectar of both studied cultivars contained all
three major sugar components: sucrose, glucose, and fructose. The nectar sugar composition of “Újfehértói fürtös” varied to a great extent according to the seasons. The
phenomenon was explained by the great fluctuation in air temperatures, which influenced
the sugar production of the cultivar to a great degree. “Pándy 48” yielded nectar with
quite stable concentration and composition in the studied four seasons.
The other research group studied nectar of the most planted sour cherry cultivar
in Serbian orchards, “Oblačinska” sour cherry, an autochthonous cultivar [64].
Investigation included 16 nectar samples of “Oblačinska” sour cherry clones. Both
the content of sugars and sugar alcohols were studied using high performance anion
exchange chromatography with pulsed amperometric detection (HPAEC/PAD).
Carbohydrates were separated on a CarboPac® PA10 pellicular anion-exchange
column. Total of 14 sugars and 6 sugar alcohols were determined, showing great
variability in carbohydrate profiles among studied genotypes. Nectars from several
sour cherry clones stood out based on the notably different concentrations of the
individual sugars and sugar alcohols. Such an unequaled nectar composition was
related to the assumption that Oblačinska sour cherry is not a cultivar but mixture of
many different genotypes.
As reported in [41], during 4-year study sucrose level in cultivars „Újfehértói
fürtös “and „Pándy 48 “ranged from 18–59 mg/mL and from 27–59 mg/mL,
762
M. F. Akšić et al.