The general increase in temperature, together with sudden episodes of extreme temperatures, are increasingly impacting plant species in the present climate change scenario. Limoniastrum monopetalum is a halophyte from the Mediterranean Basin, exposed to broad daily and seasonal changes in temperature and extreme high temperatures. We studied the photosynthetic responses (chlorophyll fluorescence dynamics and gas exchange) of L. monopetalum leaves exposed to temperatures from -7.5°C to +57.5°C under darkness in controlled laboratory conditions. L. monopetalum presented its optimum temperature for photosynthesis around +30°C. The photosynthetic apparatus of L. monopetalum exhibited permanent damages at > +40.0°C. L. monopetalum tolerated, without permanent damages, temperatures as low as -7.5°C in darkness. L. monopetalum appears as a plant species very well adapted to the seasonality of the Mediterranean climate, which may work as a pre-adaptation to stand more extreme temperatures in the actual context of accelerating climate change.

• Klíčová slova
• Mediterranean climate, chlorophyll fluorescence, climate change, gas exchange, heat wave, stressor,
• Publikační typ
• časopisecké články MeSH

Although the chloroplast movement can be strongly affected by ambient temperature, the information about chloroplast movement especially related to high temperatures is scarce. For detailed investigation of the effects of heat stress (HS) on tobacco leaves (Nicotiana tabacum L. cv. Samsun), we used two different HS treatments in dark with wide range of elevated temperatures (25-45 degrees C). The leaf segments were either linearly heated in water bath at heating rate of 2 degrees C min(-1) from room temperature up to maximal temperature (T (m)) and then linearly cooled down to 25 degrees C or incubated for 5 min in water bath at the same T (m) followed by 5 min incubation at 25 degrees C (T-jump). The changes in light-induced chloroplast movement caused by the HS pretreatment were detected after the particular heating regime at 25 degrees C using a method of time-dependent collimated transmittance (CT) and compared with the chlorophyll O-J-I-P fluorescence rise (FLR) measurements. The inhibition of chloroplast movement started at about 40 degrees C while the fluorescence parameters responded generally at higher T (m). This difference in sensitivity of CT and FLR was higher for the T-jump than for the linear HS indicating importance of applied heating regime. A possible influence of chloroplast movement on the FLR measurement and a physiological role of the HS-impaired chloroplast movement are discussed.

• MeSH
• chlorofyl chemie   metabolismus   MeSH
• chloroplasty metabolismus   účinky záření   ultrastruktura   MeSH
• fluorescence MeSH
• fotochemie MeSH
• fotosyntéza fyziologie   MeSH
• fototropismus fyziologie   účinky záření   MeSH
• fyziologický stres fyziologie   MeSH
• listy rostlin cytologie   metabolismus   MeSH
• pohyb buněk fyziologie   účinky záření   MeSH
• světelná stimulace MeSH
• světlo MeSH
• tabák cytologie   metabolismus   účinky záření   MeSH
• teplota MeSH
• vysoká teplota škodlivé účinky   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• chlorofyl MeSH