Pospíšilová J., Čatský J., Solárová J., Tichá, I.
BIOLOGIA PLANTARUM 29: 415-421, 1987

Klíčová slova: photosynthesis, carbon dioxide concentration, irradiance, leaf anatomy
Abstrakt: Abstraet. Regencrants from tobacco (2Vicotiana tabacum L. cv. White Burley) 1( af segments cultivated in vitro in vessels with solid agar medium under usual conditions (plantlets) grow under very tow h-radiance (I = 40 ~tmol m -2 s-l), very high relative humidity (more than 90 %) and decreased CO2 concentration (Ca) during light period. In comparison with seedlings of a similar number of leaves and similar total leaf area grown in sand and nutrient solution, the plantlots had lower dry mass of shoots and roots per plant and thinner leaves almost without trichomes and epicuticular waxes. Due to a low transpiration rate under high relative humidity the water potential of plantlet leaves was higher than that of seedhng leaves and the difference in water potential between leaves and medium was lowel. The rate of water loss from leaves detached from plantlets was considerably faster than that from seedlings under the same conditlons (I= 110 Izmol m -2 s -1, temperature 30 ~ relative humidity 50 ~o). Net photosynthetic rates (PN) of leaves of plantlets and seedlings measured under saturating I, natural ca and the leaf temperature 20 ~ were similar, nevertheless the shape of curves relating P~ to ca indicated some differences in photosynthetic parameters (e.g. saturation of PN under lower ca, higher CO2 compensation concentration in plantlets than m seedlings). Similarly compensation and saturating I were lower m plantlets than in seedlings. The shape of transpiration curves as well as the expressive linear phases of Ps(ca) and PN(I) curves of plantlet leaves indicated ineffective stomatal control of gas exchange. These results were confirmed by microscopic observatmns of stomatal movements in situ
DOI: 10.1007/Bf02882209 Autoři z ÚEB: Jana Pospíšilová