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Transverse section through the blade of the 3 rd leaf from the plant tip developed on the main stem of selfgrafted (control)_of cucumber plants (90 days old) grown under different salinity levels and grafting ; AControl (self grafted plants grown under non-salinized condition. B-Self grafted plants grown under 50 mM of salinity. C-Self grafted plants grown under 100 mM of salinity. D-Grafted plants grown under 0 level of salinity. E-Grafted plants grown under 100 mM of salinity.
Source publication
Cucumber is often affected by salinity due to its highly susceptible to soil salinity even at low
electrical conductivity in the saturated soil extract. This study found that cucumber grafting on salt
resistance rootstock of pumpkin can represent an interesting tool to alleviate reduce biomass and yield
losses caused by salinity stress. Grafted pla...
Context in source publication
Context 1
... (9) and Fig (2) show that, salinity decreased diameter of the midvein and the decrease was a concentration dependent. Similarly, salinity decreased diameter of lamina in the blade of the leaf developed on the medium portion of the main stem and the decrease was accompanied with a reduction in palisade and spongy tissues diameter. Also, comparing to the corresponding control, the midvein bundle dimensions (length and width) were decreased due to salinity and the decrease was accompanied with a decrease in the average number of xylem rows per midvein bundle and vessel diameter relative to the control. Similar results were reported by Dawood et al., (2014) on Vicia faba. Comparing self-grafted cucumber plants (control) with those grafting on pumpkin rootstock, the microphotographs and the tabulated data show that grafting increased diameter of both midvein and lamina of cucumber leaf blades more than the control. The increase in lamina diameter was accompanied with an increase in diameter of palisade and spongy tissues compared to the self-grafted plants. Likewise, the main vascular bundle of the midvein was increased in size (length and width) as a result of grafting which mainly due to the increase in its dimensions. However, the average number of xylem rows per midvein bundle was increased due to production of more vessels which amount to more total active conductivity area to cope with vigorous growth resulting from grafting. No available data were detected in this respect. However, it could be concluded that although the processes that regulate water and nutrients uptake are complex, it is clear that roots and shoot structures plays an important role in maintaining favorable plant water relations (Stendle and Peterson, 1998). In line with this Dawood et al., (2014) has suggested that the vessel density provides an estimate of the mean diameter of its components in the xylem, a factor strongly related to water conductivity. Accordingly, the changes in cell structure in the stem and leaves of cucumber plants. In the present investigation might have improved plant tolerance to salinity stress and/or self grafted grown in pots (restricted roots) situation and induced suitable morphological and physiological responses to adapt to the adverse condition. Zaharah and Razi (2009) found that a striking secondary branch feature in the mango plants grown under restricted rooting volume and water stress conditions was a significant reduction in the size of epidermal cells. The smallest size of straight (not sinuous) walls of the epidermal cells may contribute to the greater resistance against collapse than in the large cells. Furthermore, when water availability is low, the cortex thickness decreases and collapses the outer cortex layer in the branches under both restricted and control growth. ...
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Citations
Drought and salinity are the major abiotic stress factors negatively affecting the morphophysiological, biochemical, and anatomical characteristics of numerous plant species worldwide. The detrimental effects of these environmental factors can be seen in leaf and stem anatomical structures including the decrease in thickness of cell walls, palisade and spongy tissue, phloem and xylem tissue. Also, the disintegration of grana staking, and an increase in the size of mitochondria were observed under salinity and drought conditions. Drought and salt stresses can significantly decrease plant height, number of leaves and branches, leaf area, fresh and dry weight, or plant relative water content (RWC%) and concentration of photosynthetic pigments. On the other hand, stress-induced lipid peroxidation and malondialdehyde (MDA) production, electrolyte leakage (EL%), and production of reactive oxygen species (ROS) can increase under salinity and drought conditions. Antioxidant defense systems such as catalase, peroxidase, glutathione reductase, ascorbic acid, and gamma-aminobutyric acid are essential components under drought and salt stresses to protect the plant organelles from oxidative damage caused by ROS. The application of safe and eco-friendly treatments is a very important strategy to overcome the adverse effects of drought and salinity on the growth characteristics and yield of plants. It is shown that treatments with plant growth-promoting bacteria (PGPB) can improve morphoanatomical characteristics under salinity and drought stress. It is also shown that yeast extract, mannitol, proline, melatonin, silicon, chitosan, α -Tocopherols (vitamin E), and biochar alleviate the negative effects of drought and salinity stresses through the ROS scavenging resulting in the improvement of plant attributes and yield of the stressed plants. This review discusses the role of safety and eco-friendly treatments in alleviating the harmful effects of salinity and drought associated with the improvement of the anatomical, morphophysiological, and biochemical features in plants.
The present experiments were performed to determine the effects of Zn (20 µM and 200 µM) and Ni (1 µM and 100 µM) on the growth and metabolic activities in the roots, shoots, and spikes of wheat ( Triticum aestivum L.) cv. Gimiza 11 grown under different salinity conditions. In addition to identifying the osmotic tolerance of wheat, the roles of Zn and Ni in alleviating osmotic stress were examined. The root was the organ most sensitive to osmotic stress, whereas the shoot was the most resistant, and the spike was the intermediate. These three organs negatively responded to increasing osmotic stress levels, as fresh and dry matter decreased, and related biochemical parameters were adversely affected. However, fresh and dry matter were generally elevated when plants were supplemented with Zn or Ni under increasing osmotic stress. The sensitivity of roots was associated with depletion in the concentrations of sugars and free proline, whereas soluble protein and amino acid levels were increased. The stress tolerance of shoots and spikes was accompanied by an increase in soluble sugars, soluble proteins, and proline, while amino acid levels increased in spikes only. The Na ⁺ and K ⁺ content in wheat plants increased with increasing NaCl-induced osmotic stress levels. In turn, the accumulation and partitioning of Na ⁺ and K ⁺ did not vary among the three organs, both at different salt concentrations and between Zn or Ni treatments. Moreover, the present results show that the concentrations of anthocyanins, flavonoids, and l -ascorbic acid increased under exposure to osmotic stress and did not change significantly under Zn or Ni treatments.
