Relationship of leaf ultrastructure of mangrove Kandelia candel (L.) Druce to salt tolerance

Abstract

ABSTRACT:The leaf ultrastructure of mangrove Kandelia candel (L.) Druce planted in pots under different salinity conditions was compared under a transmission electron microscope (TEM). The results showed that the plasmalemma in plants grown in salinity conditions of 0‰ treatment (control) and 25‰ treatment was tightly combined, while in plants with salinity of 50‰ treatment, the plasmalemma crimpled remarkably and plasmolysis occurred. The nucleus and its two-layer membranes were obvious in control plants. In the case of 25‰ treatment, the membrane breakdown was observed, nucleoplasm dispersed in cytoplasm, and the electron density of cells was lower than that in control plants. In plants treated with 50‰ salinity the nucleus collapsed and no structure of the nucleus could be observed. As far as chloroplasts in control plants were concerned, they were oblong with a typical arrangement of grana and stroma thylakoids and one or two grains of starch. However, the chloroplasts in plants treated with 25‰ salinity were swelling and usually contained more grains of starch and few plastoglobuli. Most chloroplasts had a reduced number of grana, particularly of thylakoids in grana as compared with control plants. The chloroplasts of plants treated with 50‰ salinity had a considerably reduced system of grana and stroma thylakoids, and sometimes they were even deformed morphologically. They were mixed-up and contained more grains of starch and plastoglobuli. The indistinct structure of mitochondrial cristae was observed only in plants treated with 50‰ salinity. These showed that mitochondria are cell organs less sensitive to hypersaline conditions than chloroplasts and nucleus, and it was deduced that respiration was more conservative to an environment change than photosynthesis.

Effect of Silica on Physiological and Ultrastructure Characters in Barley (Hordeum Vulgare L.) Plant Under Salt Stress

“…Plastoglobuli, which were greater in number and size in chloroplasts from leaves from the hypersaline site, may have been induced by lipid release upon thylakoid destruction under salt stress (Barhoumi et al, 2007) or due to premature cellular aging and senescence (Kelly et al, 1982). Increased plastoglobuli were also reported in chloroplasts of the mangrove Kandelia candel after salt treatment (Qiu et al, 2005). The ultrastructural changes observed mainly in the chloroplast of mesophyll cells of salt treated-plants suggest metabolic disorders in these organelles.…”

Hypersalinity effects on leaf ultrastructure and physiology in the mangrove Avicennia marina

“…Increased plastoglobuli were also reported in chloroplasts of the mangrove Kandelia candel after salt treatment (Qiu et al, 2005). Mitochondrial aberrations, observed in leaves from the hypersaline site, such as fragmented envelopes with vacuolated and swollen cristae, were also reported for salt stressed, herbaceous Agrostis stolonifera (Smith et al, 1982), rice (Rahman et al, 2002;Yamane et al, 2003) and Atriplex halimus (Kelly et al, 1982).…”

“…Although Avicennia is one of the most salt tolerant mangroves (Ball, 1988), there are few studies on the effects of hypersalinity on morphological and physiological responses under natural conditions (Gordon, 1993;Lin and Sternberg, 1992;Naidoo, 2010;Sobrado and Ball, 1999). The effects of hypersalinity on leaf ultrastructure of mangroves in particular, and of halophytes in general have not been adequately addressed (Barhoumi et al, 2007;Qiu et al, 2005;Schmitz et al, 2008).…”

Seawater spray injury to Quercus acutissima leaves: Crystal deposition, stomatal clogging, and chloroplast degeneration

“…Overall cytoplasmic disintegration and reduced cytoplasm indicated high levels of necrosis, which had virtually no water (Griffiths and Orians,2003). Detachment of plasma membrane from the cell wall has been also noted in bacteria (Pianetti et al,2009) as well as plants (Qiu et al,2005) exposed to stressful salinity. As organelles that are particularly sensitive to pollutants and other stress factors, chloroplasts are thought to have undergone profound structural alterations, probably owing to the disturbance of membrane systems (Bussotti et al,1997).…”

“…In addition, salinity caused the development of an undulating thylakoid system and numerous plastoglobuli in most of the mesophyll chloroplasts of a halophytic salt excreter species (Barhoumi et al,2007). A mangrove species treated with high salinity contained a considerably reduced system of thylakoids (Qiu et al,2005). X‐ray microanalysis was performed with polymerized root sections of poplar (Chen et al,2002) and mangrove species (Li et al,2008) for probe measurements of sodium and chloride concentrations.…”