REGULAR ARTICLE
UV-B radiation does not limit carbohydrate level and carbohydrate metabolism in cucumber leaves
Magdalena Rybus-Zając, Jan Kubiś, Jan Bocianowski
Commun. Biometry Crop Sci. (2014) 9 (1), 3-14.
ABSTRACT
Cucumber is a vegetable exhibiting relatively high
sensitivity to environmental stress factors.
When it is grown outdoors, from early stages of development
there is a real risk of exposure to elevated UV-B radiation.
In order to explain the effects of time-dependent UV-B doses on
carbohydrate level and metabolism, the photosynthetic activity,
accumulation of carbohydrates and activities of carbohydrate-related
enzymes were determined in the cucumber leaves.
Elevated UV-B radiation led to an increase in the rate of photosynthesis,
which was reflected by an increase in SPAD values. Higher photosynthetic
activity resulted in an increase in levels of soluble sugars.
In view of the above-mentioned results, radiation stress led to a
UV-B time-dependent dose increase in the activity of two enzymes
decomposing carbohydrate: invertase and glucosidase. Our results
suggest that the exposure of cucumber plants to supplemental UV-B
doses does not limit the availability of the photoassimilate.
Carbohydrates are required to provide not only respiratory energy
for protection, maintenance (and repair) of plant activity and structure,
but also provide biosynthetic carbon skeletons for secondary metabolite synthesis
Key Words: invertase; b-D-glucosidas; soluble sugars (fructose, glucose and sucrose); SPAD readings.
