Ultrastructural characteristics of callus cells of Nicotiana tabacum L. var. BELW3 grown in presence of NaCl

Abstract

An investigation by electron microscopy has been carried out on Nicotiana tabacum L. var. BELW3 callus cells grown in a medium containing different NaCl concentrations (0.1, 0.2, 0.3 M) for 60 days to study the salt effect at cell level. Control N. tabacum callus exhibited parenchymatous cell types with normal cytoplasm, nucleus, organelles and membranes, together to cells forming meristematic zones by normal mitosis and cytokinesis. The callus cells exposed to the lowest salt dose did not show specific structural changes in comparison to control cells. On the contrary, the callus cells treated with the salt at the highest doses showed alterations of chloroplasts, severe damages at nuclear and cytoplasmic level, until to a complete disorganization of the whole protoplast. Also mitochondria and the membranous system appeared injured. However, in all the salt treated callus cells amylopasts were very abundant. A peculiar phenomenon was the presence in these calli under salt stress of cells contiguous to the damaged or dead cells which appeared normal in their structure. This fact confirmed the possibility to regenerate plants from callus under salt treatment in view to obtain salt tolerant crops.

In situ experiments on the effect of low pH on the ultrastructure of the seagrasses Cymodocea nodosa and Posidonia oceanica

“…In our study, short term transfers are responsible for the disorganization of the chloroplasts, testified by the loss of their internal membrane organization. Similar responses under stress conditions have been reported for terrestrial plants, such as in cotton cells under cadmium treatment (Daud et al, 2009), cucumber and soybean cold-treated cells (Lee et al, 2002;Glinska et al, 2009), and N. tabacum callus cells under salt stress (Bennici et al, 2012). The disorganization of chloroplasts in meristematic cells (especially after 3 weeks at pH 6.8) found in the present study could be explained by the translocation of photosynthates from aboveground to belowground tissues, which has been shown to decrease the leaf chlorophyll content of Thalassia hemprichii under elevated CO 2 conditions (Jiang et al, 2010).…”

Ultrastructural and physiological responses of potato (Solanum tuberosum L.) plantlets to gradient saline stress

“…It was speculated that starch synthesis plays a role in lessening the hyperosmotic stress as osmoticum. A total disorganization of the protoplast in callus cells was reported in other plants, possibly caused by dehydration (Bennici and Tani, 2012 ). Disintegration of chloroplasts and mesophyll cells end the photosynthesis, thus, maintaining structural integrity is necessary in plant growth (Bennici and Tani, 2012 ).…”

“…In addition, ultrastructural changes at the cellular level in a salt-adapted potato callus lines grown in 150 mM NaCl (Queirós et al, 2011 ) demonstrated that salt-adapted potato cell line contained more large starch, reduced membrane system and no vesicles. Although the ultrastructural alterations induced by saline have been reported in many plant cells (Yamane et al, 2004 ; Miyake et al, 2006 ; Ferreira and Lima-Costa, 2008 ; Bennici and Tani, 2009 , 2012 ), information regarding the effects of salinity on potato cells cultured in vitro is not specified and is incomplete.…”

Growth, secondary metabolite production, and in vitro antiplasmodial activity of Sonchus arvensis L. callus under dolomite [CaMg(CO3)2] treatment

“…This fact confirmed the possibility of generating a plant from callus under dolomite treatment. It seems like Bacinni and Tani [35] study on Nicotiana tabacum L. callus.…”