Grana’s structure in mesophyll of leaves Galanthus nivalis L. under the exogenous sucrose and low temperatures influence

Fediuk O. M., Bilyavska N. O., Zolotareva O. K.
M.G. Kholodny Institute of Botany of NAS of Ukraine
e-mail: olgamuronivna@ukr.net

Annotation. In laboratory conditions, after treatment of leaves Galanthus nivalis L. whit exogenous sucrose 0.1 M, a decrease of negative influence low temperatures (–15 °C) atmospheric air on the structure grana’s was revealed due to changes of thylakoids morphometric parameters.

In the spring period of G. nivalis development, after 14 days of plants cold quenching (at a temperature of +5 °C), the treatment of leaves with exogenous sucrose (Suc) of various concentrations (0.02 and 0.1 M), led to a decrease of thylakoids number per grana, respectively by 23 and 26%, in comparison with the control (0 M sucrose), an increase length the thylakoids of grana by 16 and 74%, of the thylakoids thickness by 12 and 22%, of the width lamellar space in grana by 11 and 14% by 15 and 13%. The gran area was practically unchanged at 0.02 M Suc, but it increased greatly at 0.1 M Suc (up to 52%), mainly due to a significant increase (by 74%) of the thylakoids length (at the p≤0.05). In this case, the thylakoids had no signs of swelling and undulation, and were more tightly packed than control plants (not treated with Suc), which indicates the optimization of their structure under the influence of Suc solutions at given ambient temperatures.
With the decrease in the atmospheric air temperature to –15 °C, in the grana’s chloroplasts of control leaves appeared granularity and swelling, so the thylakoids had a pronounced undulating shape. In leaves, treated with 0.02 and 0.1 M Suc, as compared to the control, the thylakoids thickness decreased insignificantly (respectively by 4 and 3%), and the luminal space thickness by 25% at 0.1 M Suc. Despite the decrease of thylakoids luminal space thickness, there was a pronounced tendency to increase the grana’s area. At 0.02 M Suc, the value increased by 108% due to an increase in the thylakoids length (by 105%), and at 
0.1 M Suc due to an increase in the number of thylakoids by 113% (more than 2 times). The presence of high grana’s formed from tightly packed, relatively short thylakoids and the absence of thylakoids deformations indicate a positive influence of the exogenous Suc solution, on adaptation of structure grana to missal temperatures.