Anatomical changes induced by increasing NaCl salinity in three fodder shrubs, Nitraria retusa, Atriplex halimus and Medicago arborea

Abstract

Nitraria retusa and Atriplex halimus (xero-halophytes) plants were grown in the range 0-800 mM NaCl while Medicago arborea (glycophyte) in 0-300 mM NaCl. Plants were harvested after 120 days of salt-treatment. The present study was designed to study the effect of salinity on root, stem and leaf anatomy, water relationship, and plant growth in greenhouse conditions. Salinity induced anatomical changes in the roots, stems and leaves. The cuticle and epidermis of N. retusa and A. halimus stems were unaffected by salinity. However, root anatomical parameters (root cross section area, cortex thickness and stele to root area ratio), and stem anatomical parameters (stem cross section area and cortex area) were promoted at 100-200 mM NaCl. Indicating that low to moderate salinity had a stimulating effect on root and stem growth of these xero-halophytic species. At higher salinities, root and stem structures were altered significantly, and their percentages of reduction were higher in A. halimus than in N. retusa whereas, in M. arborea, they were strongly altered as salinity rose. NaCl (100-300 mM) reduced leaf water content by 21.2-56.2% and specific leaf area by 51-88.1%, while increased leaf anatomical parameters in M. arborea (e.g. increased thickness of upper and lower epidermis, palisade and spongy mesophyll, entire lamina, and increased palisade to spongy mesophyll ratio). Similar results were evidenced in A. halimus leaves with salinity exceeding 100 mM NaCl. Leaves of N. retusa were thinner in salt-stressed plants while epidermis thickness and water content was unaffected by salinity. The size of xylem vessel was unchanged under salinity in the leaf's main vein of the three species while we have increased number in M. arborea leaf main vein in the range of 200-300 mM NaCl. A longer distance between leaf vascular bundle, a reduced size and increased number of xylem vessel especially in stem than in root vascular system was evidenced in M. arborea treated plants and only at (400-800 mM) in the xero-halophytic species. The effects of NaCl toxicity on leaf, stem and root ultrastructure are discussed in relation to the degree of salt resistance of these three species. Our results suggest that both N. retusa and A. halimus show high tolerance to salinity while M. arborea was considered as a salt tolerant species.

Response of Jatropha integerrima Plants Irrigated with Different Levels of Saline Water to Nano Silicon and Gypsum

“…Also, the slight increases (insignificant) in vegetative growth and flowering parameters of salt stressed plants due to nano silicon treatments are in agreement with those reported by Kalteh et al (2014) who found that nano silicon application increased leaves fresh and dry weights of basil salinity stressed plants. Furthermore, previous studies (Rahimi et al 2011;Bayat et al 2013 ;Mateos-Naranjo et al 2013;Gengmao et al 2015 andEsmaeili et al 2015) reported that application of Si in bulk materials (potassium silicate or sodium silicate) increased growth and flowering parameters of salt stressed ornamental plants.…”

“…Also, the results of increasing total chlorophylls in salinity stressed plants due to nano silicon application are in harmony with those reported by Kalteh et al (2014). Other studies (Bayat et al 2013 ;Mateos-Naranjo et al 2013;Gengmao et al 2015 andEsmaeili et al 2015) reported that application of Si in bulk materials (potassium silicate) resulted in increasing total chlorophylls or K% in salinity stressed plants.…”

“…There was significant alterations in anatomical features of leaf, where (Fig. a) represented the effect of highest salt concentration 4000 ppm without addition of either nano silicon or gypsum, resulted in changes in the cells shapes mostly deformed (cytorrhysis) and shrunk, rigorous plasmolysis and serious disorders of cell shape and structure could be observed (Boughalleb et al 2009). bigger glandular trichomes, intercellular air spaces increased but, the thickness of the leaf, and that of the adaxial epidermis of palisade, and spongy parenchyma were significantly reduced in comparison with the same anatomical structures in (Fig.…”

Akaline, saline and mixed saline–alkaline stresses induce physiological and morpho‐anatomical changes in Lotus tenuis shoots

“…At the morphological level, NaCl alters morphological and anatomical characteristics of leaves and stems, such as leaf thickness, stem cross-section area or size and number of xylem vessels (Kilic ß et al 2007;Boughalleb et al 2009;Dolatabadian et al 2011). Whereas the relationship between salinity and morpho-anatomical plant responses has been explored to some extent, reports on the effects of alkaline or mixed salt-alkaline stresses are limited to few plant species, such as aspen (Mandre et al 2012), Pisum sativum (Gharsalli et al 2001), Catharanthus roseus (Cartmill et al 2008) and Phaseolus vulgaris (Valdez-Aguilar & Reed 2008).…”

Morpho-physiological variations in response to NaCl stress during vegetative and reproductive development of rice

“…Bahia, as occurred during the vegetative growth under 20 mM NaCl (Table 2). Boughalleb et al (2009) studying two xerohalophyte and one glycophyte species reported that the sizes of xylem element vessels in the leaf's main vein were unaffected under salinity, but the number of vessels increased. This may be related to changes in IAA contents in salt-stressed plants, as IAA concentrations control xylem differentiation.…”