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2 2009

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Photosynthetic and physiological responses of Swida hemsleyi (C.K. Schneid. et Wangerin) Sojak (Cornaceae) subjected to enhanced UV-B radiation and to nitrogen supply

Yao X., Liu Q.

Polish Journal of Ecology

2009

Vol. 57, nr 3

483-494

Atmospheric ozone remains depleted which in turn leads to the increase of UV-B radiation reaching the surface of the earth and in the same time more and more nitrogen will be imported into the terrestrial ecosystems through nitrogen deposition. These two factors will operate simultaneously. The photosynthetic and physiological responses of deciduous broad leaved species Swida hemsleyi occurring commonly at 1350-3700 m a.s.l. subjected to enhanced UV-B and to nitrogen supply were studied. The experimental design included two levels of UV-B treatments (ambient UV-B, 11.02 KJ m[^-2] day[^-1] and enhanced UV-B, 14.33 KJ m[^-2] day[^-1] and two nitrogen levels (without supplemental nitrogen supply and with supplemental nitrogen supply). An experiment was conducted in open semi-field condition in Maoxian Ecological Station of Chinese Academy of Sciences, Sichuan province, China at 1820 m a.s.l. Enhanced UV-B caused a marked decline in growth parameters, net photosynthetic rate, stomatal conductance to water vapour, chlorophyll pigments, whereas it induced an increase in rate of reactive oxygen species (ROS) production and ROS accumulation and malondialdehyde (MDA) content. Enhanced UV-B also induced an increase in leaf thickness and antioxidant compounds content, such as carotenoids and proline content. On the other hand, nitrogen supply caused an increase in some growth parameters, chlorophyll pigments and antioxidant compounds, and reduced ROS accumulation. However, nitrogen supply did not affect MDA content under enhanced UV-B, though it increased antioxidant compounds content and reduced the rate of ROS production and ROS accumulation. These results implied that enhanced UV-B brought harmful effects on Swida hemsleyi seedlings and supplemental nitrogen supply could alleviate the adverse effects of UV-B radiation on plants to some extent.

Ocena degradacji barwników chlorofilowych i karotenoidów w liofilizowanych liściach lubczyka ogrodowego (Levisticum officinale Koch.)

Polak R., Krzykowski A., Kluza F.

Chłodnictwo : organ Naczelnej Organizacji Technicznej

2009

R. 44, nr 4

50-53

Za cel pracy przyjęto ocenę wpływu parametrów liofilizacji na degradację barwników chlorofilowych i karotenoidowych w liściach lubczyka ogrodowego (Levisticum officinale Koch.). Badania prowadzono na czterech poziomach ciśnienia: 30 Pa, 63 Pa, 125 Pa, 198 Pa w zakresie temperatury od 20°C do 70°C. Wstępnie zamrażane liście (w temperaturze -30°C) liofilizowano w aparacie Alphal-4. Zawartość chlorofili oraz sumy karotenoidów w badanym materiale oznaczano metodą spektrofotometryczną, wykorzystując absorpcyjny spektrofotometr typu Diode Array (Hewlett-Packard). Sposób wykonania oznaczenia oparto na metodzie Lichtenthalera. Wykazano istotny wpływ zmiennych niezależnych (ciśnienie, temperatura) na zawartość wybranych barwników w liofilizowanych liściach.

The objective of the study was evaluation of influence of some lyophilisation parameters on chlorophyll and carotene pigments degradation rate in lovage leafs (Levisticum officinale Koch.). The study was carried out at four distinct pressure levels 30 Pa, 63 Pa, 125 Pa, and 198 Pa, in temperature range from 20°C to 70°C. Initially frozen leafs (at-30°C) were subsequently lyophilised in an Alpha 1-4 apparatus. For the estimation of chlorophyll and total carotene contents a spectrophotometric method was used and a Diode Array spectrophotometer was applied, according to the Lichtenthaler procedure. Both, temperature and pressure significant influence on the amount of analyzed pigments in lovage leafs bas been proved.