Ali Farhadi; Hossein Arouiee; Seyyed Hossein Nemati; Reza Salehi; Francesco Giuffrida
Abstract
Introduction: Salinity stress is regarded as one of the most important abiotic factors in plant limiting growth, particularly in arid and semi-arid regions. The reduction of plant growth by salinity stress has been well documented. When water supply is limited, plant structure is modified by increasing ...
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Introduction: Salinity stress is regarded as one of the most important abiotic factors in plant limiting growth, particularly in arid and semi-arid regions. The reduction of plant growth by salinity stress has been well documented. When water supply is limited, plant structure is modified by increasing the root: shoot ratio. To reduce of losses in vegetative growth and production of plant and to improve water use efficiency under saline conditions in high-yielding genotypes grafting them onto rootstocks could bereduced the effect of saline stress on plant shoot. Grafting is a routine technique in continuous cropping systems. Most of the species of cucurbits are distributed in the dry regions. The objective of this studywas investigated the effectiveness of salinity stress on accessions of cucurbita and hybrid inter specific which enter from another country to Iran.
Materials and Methods: This research was conducted in laboratory and greenhouse at the Research Center of Agricultural and Natural Resources of Isfahan during 2013-2014 growing season. A factorial experiment based on completely randomized design with three replications was conducted for rootstock and irrigation water salinity.. In the first experiment 25 seeds of rootstocks were sown in petri dishes with 10 cm diameter and irrigated by 10 ml of saline water. Rootstocks included 20 different local landraces and interspecific hybrids (C.moschata cv. Isfahan and Koshk, C.pepo cv. Alvar, Tiran, Koshk and Asgharabad, C. maxima cv. Kermanshah, Shahreza, Mohamadiyeh and Alvar, Lagenaria Siceraria, Luffa cylindrica, Trichosanthes cucumerina, RZ-Ferro, Es113, Ews910, Ews909, Ews913, 426 and Es152). Salinity stress was 6 levels (0, 2, 4, 6, 8 and 10 ds/m of NaCl). Germination, diameter of stem, height of root and stem, shoot and root fresh mass, vigor index and root: shoot ratio were evaluated. In the second experiment seeds were sown in plastic pot by soil media. Seedlings were irrigated daily with 200 ml of saline water (0, 2 and 4 ds/m) for 35 days. Excess solution was allowed to drain from the plants through drainage holes in the base of the pots. Hybrids of 152,426 and Trichosanthes cucumerina, Luffa cylindrical and Cucurbita pepo con. Pepo var. Styriaca was added. In the second phase measured shoot and root dry mass, SPAD index, relatively water content and seedling vigor index.
Results and Discussion: the results showed that all parameters were significantly influenced by salinity except root: shoot ratio in Petri dish. Salinity stress reduced chlorophyll index (SPAD), relative water content in cucurbita leaves than control (without saline) and also seeds germination, seedlings fresh mass and seedlings vigour by 51%, 53%, and 75 % respectively. .The shoot dry biomass of local landrace and inter specific hybrids in both experiment decreased linearly in response to increasing saline stress. Recorded data in Petri dish and plastic pot were significantly influenced by rootstock, whereas no significant difference was observed on germination rate and vigor index for plastic pot in greenhouse. The lowest seed germination percentage, seedling growth, vigor index and root: shoot ratio recorded on high saline concentration. NaCl threshold damage to cucurbits was evaluated 4 ds/m. Populations of C. maxima cv.Kermanshah and Shahreza, C.moschata cv. Isfahan and inters pecific hybrids Ferro, 909 and 910 were showed tolerant to salinity. It is proven that crop growth decreases with increasing saline stress (Rouphael, et al., 2012). Hybrids of C. moschata cv. Koshk, C. pepo cv. Koshk and Asgharabad, Lagenaria Siceraria, Es113 and Cucurbita pepo con. Pepo var. Styriaca were sensitive to saline stress. Kumar et al, (2008) also reported plant response to salinity depends on type of salt, salt concentration and plant genotype.
Conclusions: Salinity stress adversely affect biomass and leaf water content of cucurbita. Our results indicated that local and hybrid cucurbit plants exhibited different response to saline stress. Hybrid rootstocks 909, 910 and Ferro were tolerant to salinity. Although local landrace C. maxima. cv. Shahreza and Kermanshah, C. moschata cv. Isfahan and C. pepo cv. Tiran were tolerant to salinity. Sensitivity to saline stress was similar between some local landrace and hybrid plants. Finally, after grafting in cucurbita rootstocks needs more research to use water, wast water, NaCl and other resources of salinity and to find the most tolerant rootstock.
Azadeh Mousavi Bazaz; Ali Tehranifar; Mohammad Kafi; Ali Gazanchian; Mahmood Shoor
Abstract
Introduction: Worldwide, more than one-third of irrigated land is salinized, and in many regions, fresh water shortage has resulted in restrictions on the use of potable water for landscape irrigation. On the other hand, rapidly expanding population growth is occurring in many arid regions, where soil ...
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Introduction: Worldwide, more than one-third of irrigated land is salinized, and in many regions, fresh water shortage has resulted in restrictions on the use of potable water for landscape irrigation. On the other hand, rapidly expanding population growth is occurring in many arid regions, where soil and water salinity are problems and there are increased demands on limited fresh water resources (9). In the turf grass industry, with the increased use of saline and non-potable water, the development of turf grass landscapes in arid and seashore regions where saline soil is common, and with the use of salt for deicing roadways, the need for salinity tolerant turf grasses is very important (16).Seed germination and early seedling growth is usually the most critical stage in plant establishment, and determining successful crop production (23). Tall fescue (Festuca arundinacea Schrub.) is an important perennial cool-season grass in temperate regions and it is widely used for both forage and turf purposes (25). There is no study on the evaluation of salinity on tall fescue native populations in Iran. The major objective of this study is to determine the relative salt tolerance and growth response of native populations of tall fescue to salinity in germination stage.
Materials and Methods: In this experiment, seeds of some native populations of tall fescue (TF) (F. arundinacea Schreb) including: Semirom, Mashhad, Sanandaj, Sanajan, Yasuj, Yazd Abad, Daran, Kamyaran, Gandoman, Borujen, Nasir Abad, Alborz and commercial TF (C. TF) seeds were used. Four replicates of 25 seeds were germinated on filter papers with 5 ml of NaCl concentrations placed in 9 cm Petri dishes. NaCl concentrations included: 0, 45, 90 and 135 milimolar. The Petri dishes were transferred to germinator at 23°C.Germinated seeds were counted on the3rd, 5th, 8th, 11th and 14th days. Germination was considered to have occurred when the root length was 2 mm long. The seedling with short, thick, and spiral formed hypocotyls and stunted primary root were considered as abnormally germinated. Then, the total germination percentage, germination rate, root length and shoot length were calculated on Day 15. The vigor index was calculated as VI= (RL+SL)×GP, where for the VI, RL is the root length, SL is the shoot length and GP is the germination percentage. Root length and shoot length were measured manually with a ruler. The experimental design was a completely randomized design with 4 replications and 25 seed per replicate. The data were statistically analyzed by JMP 8.0. The difference between the means was compared using LSD values (P < 0.01).
Results and Discussion: The results indicated that the increase of salinity level leads to a significant decrease in germination percentage, germination rate, length of shoot, root and vigor index in all genotypes. Also, interaction of salinity and genotype was significant for germination percentage, germination rate, and vigor index. The highest germination percentage was related to Mashhad population at 45 milimolar, and Daran population at 90 and 135 milimolar. Also, the lowest germination percentage was related to Kamyaran population at 45 and 90 milimolar and Commercial tall fescue at 135 milimolar. Mashhad population at 135 milimolar, Daran population at 90 and 135 milimolar had the highest germination rates. The lowest germination rate was recorded at 45, 90 and 135 milimolar in Commercial tall fescue, Kamyaran and Sanandaj populations, respectively. The highest root length was seen in Commercial tall fescue at 90 and 135 milimolar, and Mashhad population at 45 milimolar. For shoot length factor, Mashhad population, Commercial tall fescue and Mashhad population had the highest lengths at 135, 90 and 45 milimolar, respectively. The highest vigor index was related to Mashhad, Daran and Mashhad populations, at 45, 90 and 135 milimolar, respectively. NaCl has an inhibitory effect on seedgermination and its effect on germination showed time course dependence for absorption of Na and Cl by thehypocotyls (28).Increasing salinity levels caused delays in seedlingemergence as a result of reducing cell division and plant growth metabolism (28). The negative effect of salinity on seed germination and early growth could be due to the toxic effects of NaCl on seeds, or to the osmotic effect, that prevents the seeds from imbibitions (21).
Conclusion: Major grasses mentioned above could tolerate 45 milimolar salinity without noticeable changes in germination traits. Mashhad and Brujen populations were least affected by 135 Mm Nacl at germination rate and percentage. Also, Daran and Mashhad populations were least affected by different salinity levels in all germination factors compared to other populations and could be suggested as salt-tolerant genotypes at germination stage.
