INFLUENCE OF REDUCTION OF ENHANCED MOUNTAIN UV-RADIATION ON
THE PHOTOSYNTHESIS AND GROWTH OF CULTURED C3-PLANTS
Valery Yu. Lyubimov ,
Alexander E. Kalevich, Institute of Soil Science and Photosynthesis RAS, Pushchino, Moscow
Region, 142292 Russia.
Said Shomansurov, Pamir Biological Institute Tajik AS, Khorog, Tajikistan.
Key words: C3-plants,
hormones, Pamir, photosynthesis, productivity, UV-radiation.
Investigation was carried
out with small radish (Raphanus sativus L.), pot marigold (Calendula
officianalis L.), red pepper (Capsicum annuum L.), and bulb onion (Allium
cepa L.). Plants were grown at the high mountain place (Pamir, near Khorog, 2320 m
over sea level) under free sky (FS), under usual polyQ-film (UF), and under transforming
polyQ-film (TF). Last one captures from 60 to 30% of UV-radiation (from 300 to 400 nm
resp.) and effectively transforms it to visible light (600-700 nm). Under light condition
using the UF the photosynthetic rate (14CO2-assimilation per leaf
fresh weight) of all species was similar (± 3-5%) to this one under FS. The small radish
and pot marigold which were grown under TF exhibited the enhanced photosynthetic
assimilation of 14CO2 (+20%), red pepper exhibited the decreased
assimilation (-22%) and bulb onion did not changes the photosynthetic rate. There was
qualitative correlation between photosynthetic activity and growth of plants: the height
of small radish and pot marigold plants were increased by 20 and 95%, respectively. The
height of red pepper plants was reduced not significantly changed (-6%) and the height of
bulb onion plants was reduced by 24%. These changes of plant growth and productivity
parameters it seemed are associated with changes of hormonal status of plants. Reduction
of the natural enhanced UV-radiation leads to complex changes in photosynthesis, hormonal
status and growth of cultured plants.