Chlorophyll fluorescence in micropropagated Rhododendron ponticum subsp. baeticum plants in response to different irradiances

Abstract

The aim of this study was to investigate acclimation of micropropagated plants of Rhododendron ponticum subsp. baeticum to different irradiances and recovery after exposure to high irradiance. Plants grown under high (HL) or intermediate (IL) irradiances displayed higher values of maximum electron transport rate (ETR max ) and light saturation coefficient (E k ) than plants grown under low irradiance (LL). The capacity of tolerance to photoinhibition (as assessed by the response of photochemical quenching, q p ) varied as follows: HL > IL > LL. Thermal energy dissipation (q N ) was also affected by growth irradiance, with higher saturating values being observed in HL plants. Light-response curves suggested a gradual replacement of q p by q N with increasing irradiance. Following exposure to irradiance higher than 1500 μmol m -2 s -1 , a prolonged reduction of the maximal photochemical efficiency of PS 2 (F v /F m ) was observed in LL plants, indicating the occurrence of chronic photoinhibition. In contrary, the decrease in F v /F m was quickly reverted in HL plants, pointing to a reversible photoinhibition.

In vitro mass propagation of Murraya koenigii L

“…Also, the presented work examining the effect of 70 days hardening periods over photosynthetic parameters, favored by the studies of various authors (Pospisilova et al, 1999;Van Huylenbroeck et al, 2000;Carvalho et al, 2001;Osorio et al, 2010). A significant decline in chlorophyll (a and b), carotenoid contents and P N rate at the initial 14 days of acclimatization period followed by enhancement with the formation of new leaves at the consequent recovery period of 21-70 days is in conformity with the findings of Kadlecek et al (1998) in Nicotiana tabacum, wherein photomixotrophically grown plantlets exhibited decrease in Chl a and b content during first week of ex vitro transplantation.…”

Acclimatization of micropropagated plantlets induces an antioxidative burst: a case study with Ulmus minor Mill.

“…These special conditions result in a formation of plants with abnormal morphology, anatomy and physiology (Pospíšilová et al 1999, Hazarica 2006, Estrada-Luna et al 2001, Pinto et al 2011. During the transfer to ex vitro conditions, in vitro plants are exposed to light intensities higher than those used under in vitro conditions, resulting usually in photoinhibition (Carvalho and Amâncio 2002a, Ali et al 2005, Osório et al 2010). In addition, the high differential vapour pressure between in vitro and ex vitro condition can induce water stress.…”

Rooting affects the photosystem II activity: in vitro and ex vitro studies on energy hybrid sorrel

“…The regenerated plantlets were successfully rooted and acclimated to ex vitro conditions with an almost 100% survival rate. It is commonly known that the transfer from in vitro to ex vitro conditions requires adaptation to the new stressful conditions (Pospíšilová et al 1999;Apóstolo et al 2005;Joshi et al 2006;Osório et al 2010). During this acclimation, plants undergo physiological and morphological changes that enable them to grow in the new environment (Pospíšilová et al 1999).…”