Study On Growth, Physiological And Biochemical And Anatomical Structure Of Cherry Stocks Under Salt Stress

Cherry which is a berry fruit trees, has a high nutritional、healthy and economic value. Itcannot be stored and transported for long time and is suitable for production near the markets.Tianjing is the third largest city in China. There is a very good market prospect. However,most parts of Tianjin are mild and moderate saline-alkali land, so the salt-tolerant stockshould be used in cherry cultivation. In order to understand the salt-tolerant mechanism ofcherry stock, Cerasus pseudocerasus、Cerasus maximowiczii、Cerasus szechuanica、Cerasustomentosa and Prunus prostrata and the difference between different species, the germinationindexes of seeds, the growth indexes, physiological and biochemical indexes of the seedlingsof Cerasus pseudocerasus、Cerasus maximowiczii and Cerasus szechuanica were analized bystress treatment of0、0.2%、0.4%、0.6%NaCl in the seed germination and the seedling growth.It was measured that indexes of seed germination included the germination rate, germinationindex, germinating energy, the initial germination days、radicle length、the tolerance, thehalf-lethal and the limit concentration of NaCl, the growth indexes included the plant height,leaf area, stem diameter, leaf number, the physiological and biochemical indexes included themembrane permeability、MDA content、content of chlorophyll a,b、SOD and POD enzymaticactivity and free proline content. The structure of epidermal cells, corneum thickness,mesophyll cell size and palisade tissue thickness of leaf cross-sections of3species(Cerasuspseudocerasus、Cerasus maximowiczii、Cerasus szechuanica)were observed under salt stressand in microscopic, and the characteristic of epidermis, corneum, stomatal、palisade tissue、vascular tissue of leaf vein, cork layer, phelloderm，vascular tissue（phloem、xylem）of the5different species were observed. All the indicators were comprehensively analyzed bysubjection function. The results showed that:1．All indexes of Cerasus pseudocerasus were the highest during germination, such as thegermination rate, germinating potential, germination index, radicle length, salt toleranceconcentration, salt tolerance and half lethal concentration and concentration of salt tolerancelimit.The result showed that the average value of Cerasus pseudocerasus was the highest of3species in different salt concentration. While, the Cerasus maximowiczii and Cerasusszechuanica were different: under0.2%and0.4%NaCl concentration, Cerasus szechuanicawas medium, while Cerasus maximowiczii was the lowest among3species. But, the resultwas opposite under0.6%NaCl concentration. Therefore the salt tolerance in germinationperiod: under low salt concentration: Cerasus pseudocerasus> Cerasus szechuanica> Cerasus maximowiczii; under high salt concentration: Cerasus pseudocerasus> Cerasusmaximowiczii> Cerasus szechuanica by comprehensive analysis.2．The4indexes of Cerasus pseudocerasus were the highest during growth period underdifferent salt stress, such as the plant height、number of blade、leaf area、stem diameter andphysiological, the stem diameter of Cerasus maximowiczii was bigger than that of Cerasusszechuanica,while the other three index were smaller than Cerasus szechuanica. So thecomparison of salt tolerance in cherry seedlings growing period: Cerasus pseudocerasus>Cerasus maximowiczii> Cerasus szechuanica.3．With the increase of NaCl concentration，the content of chlorophyll a,b of Cerasuspseudocerasus and Cerasus szechuanica increased and then declined, while the Cerasusmaximowiczii almost didn’t change. The MDAcontent of Cerasus pseudocerasus increasedunder0.2%NaCl treatment but significantly reduced under0.4%concentration. SODenzymatic activity first increased thenreduced, while it didn’t change under highconcentration (0.6%); POD enzymatic activity is highest under0.4%concentration and it wasthe same to free proline content, while it then reduced. The MDA content of Cerasusszechuanica first increased and then reduced, but the content was always in a high level; SODand POD enzymatic activity increased and then reduced. They were significantly reducedunder high concentration salt stress. Free proline content peaked at0.2%, and quickly reducedunder0.4%and0.6%. The MDA content and SOD enzymatic activity of Cerasusmaximowiczii almost didn’t change under low concentration, while MDA content increasedunder0.6%, and SOD enzymatic activity decreased significantly; what’s more, PODenzymatic activity decreased after a slow rate increasing，which had the same tend with freeproline, the difference is that free proline increased significantly under0.6%concentration.Analysis shows salt tolerance comparison: Cerasus pseudocerasus> Cerasus maximowiczii>Cerasus szechuanica.4、In the5cherry, leaf and palisade tissue of Cerasus pseudocerasus were the thickestand its leaf corneum was thick, while the stomatal density was smallest. The number ofcatheter、xylem parenchyma, vascular bundles in the stem and xylem catheter were the most,which meaned Cerasus pseudocerasus had more anatomical characteristics of salt tolerance.The epidermis cell thickness of Prunus prostrata was the thickest, its leaf corneum andmesophyll, palisade tissue were thick, the stomatal density was smallest. The leaf corneum of Cerasus szechuanica was the thickest, mesophyll and palisade tissue were thick. The stomataldensity of Cerasus tomentosa was the smallest and the cuticular layer was thick. The stomatalof Cerasus maximowiczii was the minimum, the leaf corneum and palisade tissue was thick.So, According to the salt anatomical characteristics of5cherry, the salt tolerance comparison:Cerasus pseudocerasus> Prunus prostrata>Cerasus maximowiczii, Cerasus szechuanica andCerasus tomentosa5、The epidermal cell layer、corneum and spongy tissue of Cerasus pseudocerasus gotthicker， the palisade tissue became thinner, which made the leaf thinner. The change ofstructure was in favour of reducing the evaporation of the water and water consumption.While it’s just opposite to Cerasus maximowiczii and Cerasus szechuanica. Under salt stress,the epidermal cell layer corneum became thinner, the spongy tissue and the leaf got thicker.So according to adaptive change of anatomical structure under salt stress, the salt tolerancecomparison: Cerasus pseudocerasus> Cerasus maximowiczii and Cerasus szechuanica.Integrating the characteristic in seed germination、Seedling stage growth and the changein physiological and anatomic structure, the salt tolerance comparion: Cerasuspseudocerasus> Cerasus maximowiczii and Cerasus szechuanica. Otherwise, according to theanalysis of anatomical structure of blades and stem, the salt tolerance comparison: Cerasuspseudocerasus> Prunus prostrata> Cerasus maximowiczii, Cerasus szechuanica and Cerasustomentosa.