Saltgrass, a True Halophytic Plant Species for Sustainable Agriculture in Desert Regions
محورهای موضوعی : Research On Crop Ecophysiology
1 - School of Plant
Sciences, the University of Arizona Tucson, AZ 85721, USA
کلید واژه: arid regions, Sustainable agriculture, Keywords: Salt stress, Saltgrass, Saline soil reclamation, Combating desertification processes,
چکیده مقاله :
Mohammad Pessarakli Professor. School of Plant Sciences, the University of Arizona Tucson, AZ 85721, USA * Corresponding author E-mail:pessarak@ag.arizona.edu Received: 4 April 2013 Accepted: 12 November 2013 Abstract Continuous desertification of arable lands due to urbanization, global warming, and shortage of water mandates use of low quality/saline water for irrigation, especially in the regions experiencing water shortage. Using low quality/saline water for irrigation imposes more stress on plants which are already under stress in these regions characterized with saline soils and shortage of water. Thus, there is an urgent need for finding salt/drought tolerant plant species to survive/sustain under such stressful conditions. Since the native plants are already growing under such conditions and are adapted to these stresses, they are the best and the most suitable candidates to be manipulated for use under these stressful conditions. If stress tolerant species/genotypes of these native plants are successfully identified, there would be a substantial savings in cultural practices and inputs in using them by the growers and will result in substantial savings in the currencies of the countries. My investigations at the University of Arizona on saltgrass (Distichlis spicata L.), a euhalophytic plant species, have indicated that this plant has an excellent drought and salinity tolerance with a great potential to be used under harsh and stressful environmental conditions. This grass has multi usages, including animal feed, soil conservation, saline soils reclamation, and combating desertification processes. The objectives of this study were to find the most salt tolerant of various saltgrass genotypes for use in arid and semi-arid regions for sustainable agriculture and biologically reclaiming saline soils. Twelve saltgrass clones were studied in a greenhouse, using the hydroponics technique to evaluate their growth responses in terms of shoot and root lengths and DM weights, and general grass quality under salt stress conditions. Grasses were grown vegetatively in Hoagland solution for 90 days prior to exposure to salt stress. Then, 4 treatments [EC of 6 (control), 20, 34, and 48 dSm-1 salinity stress] were replicated 3 times in a RCB design experiment. Grasses were grown under these conditions for 10 weeks. During this period, shoots were clipped bi-weekly, clippings were oven dried at 65o C and DM weights were recorded, and shoot and root lengths were also measured. At the last harvest, roots were also harvested, oven dried, and DM weights were determined. General grass quality was weekly evaluated and recorded. Although, all the grasses showed a high level of salinity tolerance, there was a linear reduction in their growth responses as salinity level increased. However, there was a wide range of variations observed in salt tolerance of these saltgrass clones. The superior stress tolerant genotypes were identified which could be recommended for sustainable production under arid regions and combating desertification. This grass proved to not only have a satisfactory growth under the harsh desert conditions, but also to substantially reduce salinity level of the rhizosphere, which indicates that saltgrass can effectively be used for biological salinity control or reclamation of desert saline soils and combating desertification processes.
Original Research Research on Crop Ecophysiology Vol. 9/1, Issue 1 (2014), Pages: 1 -11 Saltgrass, a True Halophytic Plant Species for Sustainable Agriculture in Desert Regions Mohammad Pessarakli Professor. School of Plant Sciences, the University of Arizona Tucson, AZ 85721, USA * Corresponding author E-mail:pessarak@ag.arizona.edu Received: 4 April 2013 Accepted: 12 November 2013 Abstract Continuous desertification of arable lands due to urbanization, global warming, and shortage of water mandates use of low quality/saline water for irrigation, especially in the regions experiencing water shortage. Using low quality/saline water for irrigation imposes more stress on plants which are already under stress in these regions characterized with saline soils and shortage of water. Thus, there is an urgent need for finding salt/drought tolerant plant species to survive/sustain under such stressful conditions. Since the native plants are already growing under such conditions and are adapted to these stresses, they are the best and the most suitable candidates to be manipulated for use under these stressful conditions. If stress tolerant species/genotypes of these native plants are successfully identified, there would be a substantial savings in cultural practices and inputs in using them by the growers and will result in substantial savings in the currencies of the countries. My investigations at the University of Arizona on saltgrass (Distichlis spicata L.), a euhalophytic plant species, have indicated that this plant has an excellent drought and salinity tolerance with a great potential to be used under harsh and stressful environmental conditions. This grass has multi usages, including animal feed, soil conservation, saline soils reclamation, and combating desertification processes. The objectives of this study were to find the most salt tolerant of various saltgrass genotypes for use in arid and semi-arid regions for sustainable agriculture and biologically reclaiming saline soils. Twelve saltgrass clones were studied in a greenhouse, using the hydroponics technique to evaluate their growth responses in terms of shoot and root lengths and DM weights, and general grass quality under salt stress conditions. Grasses were grown vegetatively in Hoagland solution for 90 days prior to exposure to salt stress. Then, 4 treatments [EC of 6 (control), 20, 34, and 48 dSm-1 salinity stress] were replicated 3 times in a RCB design experiment. Grasses were grown under these conditions for 10 weeks. During this period, shoots were clipped bi-weekly, clippings were oven dried at 65o C and DM weights were recorded, and shoot and root lengths were also measured. At the last harvest, roots were also harvested, oven dried, and DM weights were determined. General grass quality was weekly evaluated and recorded. Although, all the grasses showed a high level of salinity tolerance, there was a linear reduction in their growth responses as salinity level increased. However, there was a wide range of variations observed in salt tolerance of these saltgrass clones. The superior stress tolerant genotypes were identified which could be recommended for sustainable production under arid regions and combating desertification. This grass proved to not only have a satisfactory growth under the harsh desert conditions, but also to substantially reduce salinity level of the rhizosphere, which indicates that saltgrass can effectively be used for biological salinity control or reclamation of desert saline soils and combating desertification processes. Keywords: Salt stress, Arid regions, Saltgrass, Sustainable agriculture, Saline soil reclamation, Combating desertification processes Introduction Saltgrass (Distichlis spicata (L.) Greene var. stricta (Gray) Beetle) (Gould, 1993), indigenous to the Southwest, a potential animal feed plant, saline soil reclamation, soil establishment/erosion control, and use as a turfgrass species for lawns/recreation areas, grows in very poor to fair condition soils, in both salt-affected soils and soils under poor fertility as well as drought and harsh environmental conditions (Gould, 1993 O’Leary and Glenn, 1994). Its dominant and most common habitats are arid and semi-arid regions (Marcum et al., 2005 Pessarakli and Kopec, 2010 Pessarakli and Kopec, 2011 Pessarakli et al., 2011a, 2011b Pessarakli et al., 2012). The plant is abundantly found in areas of the western parts of the United States as well as on the sea-shores of several Middle-Eastern countries, Africa, South and Central American countries (Pessarakli et al., 2005 Pessarakli, 2007 Pessarakli and Kopec, 2010 Pessarakli et al., 2011a, 2011b Pessarakli et al., 2012). The species can be manipulated to modify its performance and increase its yield and productivity. This plant has multi-purpose usages. It can be substituted for animal feeds like alfalfa, used for biological reclamation of saline soils, soil conservation and erosion control for covering road sides and soil surfaces in lands with high risks of erosion, and use as a turfgrass species. Recently, the United States Golf Association (USGA) and the US Bureau of Land Management (BLM) have shown a great deal of interest in financing research work on this plant to use it as a turfgrass or for soil erosion control and saline soil reclamation. Most of these research works have been conducted at the University of Arizona and Colorado State University. Consequently, the USGA and the BLM funds for the investigations on this grass species have been allocated to these institutions. Positive and promising results have already been obtained from these studies (Gessler and Pessarakli, 2009 Kopec et al., 2000, 2001a, 2001b, 2006 Marcum et al., 2001, 2005 Pessarakli, 2005a, 2005b, 2007, 2008 Pessarakli and Kopec, 2005, 2006, 2008a, 2008b, 2010 Pessarakli and Marcum, 2000 Pessarakli et al., 2001a, 2001b, 2001c, 2003, 2005, 2008 2011a, 2011b, 2012). Most of the published reports on saltgrass, including those of Sigua and Hudnall (1991), Sowa and Towill (1991), Enberg and Wu (1995), Miyamoto et al. (1996), Rossi et al. (1996), and Miller et al. (1998) are concern only with the growth of this species, usually concentrated only on one grass genotype or the species of a specific location. The objectives of this study were to find the most salinity tolerant of various saltgrass genotypes and to recommend them as the potential species for use under arid, semi-arid, and areas with saline soils and limited water supplies for sustainable agriculture and combating desertification. Materials and Methods Plant Materials Twelve inland saltgrass (Distichlis spicata L.) clones (A37, A49, A50, A60, 72, A86, A107, A126, A136, A138, 239, and 240), collected from different locations in several western states of the United States (Arizona, California, Nevada, and Colorado) were used in a greenhouse experiment to evaluate their growth responses in terms of shoot and root lengths as well as shoot and root dry weights, and visual grass quality under different levels of salinity stress conditions, using a hydroponics technique. Plant Establishment The plants were grown as vegetative propagules in cups, 9 cm diameter and cut to 7 cm height. Silica sand was used as the plant anchor medium. The cups were fitted in plywood lid holes and the lids were placed on 42 cm X 34 cm X 12 cm Carb-X polyethelene tubs containing half strength Hoagland nutrient solution (Hoagland and Arnon, 1950). Three replications of each treatment were used in a randomized complete block (RCB) design in this investigation. The plants were allowed to grow in this nutrient solution for 8 weeks. During this period, the plant shoots were harvested weekly in order to reach full maturity and develop uniform and equal size plants. The harvested plant materials were discarded. The culture solutions were changed biweekly to ensure adequate amount of plant essential nutrient elements for normal growth and development. At the last harvest, 10th week, the roots were also cut to 2.5 cm length to have plants with uniform roots and shoots for the stress phase of the experiment. Salt Treatments The salt treatments were initiated by gradually raising the EC (electrical conductivity) of the culture medium to 6, 20, 34, and 48 dS m-1 by adding Instant Ocean salt to the nutrient solutions, followed procedures used by Pessarakli and Kopec (2005, 2006). The EC of the culture solutions were raised by increments of 6 (first day) and 7 every other day until the desired EC levels were reached. Four treatments were used, including control (EC = 6 dS m-1, several of my salinity stress experiments showed that saltgrass at relatively low level of salinity for this high salinity tolerant halophytic grass performs better than growing in normal condition, therefore, for the control, usually, I use EC = 6 dS m-1), 20, 34, and 48 dS dS m-1 (EC = 48 dS dS m-1 is a good representative of the EC of sea water which is normally between 30 and 60 dS dS m-1). The culture solution levels in the tubs were marked at the 10 liter volume, and the solution conductivities were monitored/adjusted to maintain the prescribed treatment salinity levels. After the final salinity levels were reached, the shoots and the roots were harvested and the harvested plant materials were discarded prior to the beginning of the data collection of the salinity stress phase of the experiment. Then, plant shoots were harvested bi-weekly for 10 weeks for the evaluation of the dry matter (DM) production. At each harvest, both shoot and root lengths were measured and recorded. The harvested plant materials were oven dried at 65o C and DM weights were measured and recorded. The recorded data were considered the bi-weekly plant DM production. At the termination of the experiment, the last harvest, plant roots were also harvested, oven dried at 65o C, and dry weights were determined and recorded. Weekly visual evaluation of the grass quality was also performed and recorded. The data were subjected to Analysis of Variance, using SAS statistical package (SAS Institute, Inc. 1991). The means were separated, using Duncan Multiple Range test. Results and Discussion Shoot Dry Matter (DM) Weight The shoot dry matter (DM) weights of all the saltgrass clones decreased with increased salinity stress level. A marked reduction in shoot dry weights occurred at the higher salinity levels (EC 34 and EC 48 dS m-1) across all the clones (Table 1). For the dry weights of the shoots, the gap between the means of the stressed plants and the control (EC = 6 dS m-1) was wider as the exposure time to salinity stress progressed. Root Dry Matter (DM) Weight The effect of salinity on root dry weight was less severe compared to that of shoot dry mass (Table 2). Similar results were reported on different genotypes/ accessions/clones of this grass in other studies by this author and his co-workers Table 1. Saltgrass shoot dry weight (DM) under salt stress Grass ID Shoot 6 DM (g)* 20 at EC 34 dS m-1 48 A37 1.10cde** 0.57bcde 0.27cde 0.15c A49 1.26bcd 0.77ab 0.32bcde 0.13c A50 1.65ab 0.60bcd 0.21de 0.17bc A60 1.03cde 0.38e 0.17e 0.13c 72 1.38bc 0.82a 0.38abc 0.19bc A86 1.66ab 0.86a 0.26cde 0.14c A107 0.95de 0.52cde 0.30bcde 0.20bc A126 0.83e 0.41de 0.18e 0.15c A128 1.37bc 0.73abc 0.52a 0.30a A138 1.09cde 0.46de 0.36abcd 0.25ab 239 1.67ab 0.88a 0.44ab 0.15c 240 1.94a 0.91a 0.49a 0.24ab *The values are the means of 3 replications of each treatment. **The values followed by the same letters in each column are not statistically significant at the 0.05 probability level. Table 2. Saltgrass root dry weight (DM) (cum. values) under salt stress Grass ID Root 6 DM (g)* 20 at EC 34 dS m-1 48 A37 0.74cde** 0.99def 1.10cdef 0.78cd A49 1.61b 1.11cdef 1.56bcd 1.03bcd A50 1.83b 1.65a 1.94abc 0.74cd A60 1.46bc 1.71a 1.31bcde 0.84bcd 72 0.77cde 0.93def 0.72def 0.50d A86 1.06bcde 1.18bcde 0.76def 0.81bcd A107 0.68de 0.84ef 0.53ef 0.68cd A126 0.50e 0.68f 0.26f 0.48d A128 3.46a 1.50abc 2.05ab 1.18bc A138 1.17bcde 0.88def 0.43ef 2.28a 239 1.31bcd 1.30abcd 2.82a 1.21bc 240 3.36a 1.63ab 1.25bcde 1.42b *The values are the means of 3 replications of each treatment. **The values followed by the same letters in each column are not statistically significant at the 0.05 probability level. (Marcum et al., 2005 Pessarakli, 2007, 2008 Pessarakli and Kopec, 2005, 2006, 2010 Pessarakli and Marcum, 2000 Pessarakli et al., 2001c, 2005, 2008, 2011a, 2012). Sagi et al. (1997) and Pessarakli and Tucker (1985, 1988) also found the adverse effect of salinity stress was more pronounced on plant shoots than the roots. This is a common phenomenon in halophytic plant species that usually under salinity stress conditions, their shoots are more severely affected than their roots. Clone 240 had excellent root growth at EC 6 dS m-1 and the second highest root production at EC 48 dS m-1 (Table 2), but had poor quality under high salinity level. The same was true for clone 239. Clone A138 had twice the root mass of most other clones at EC 48 dS m-1, but essentially had no green foliage at EC 48 dS m-1 at the close of the test. At EC 6 dS m-1, clone A128 produced twice the test mean average for roots (3.46 g) with fairly good absolute root production afterwards, but showing a significant change in root production as EC levels increased (Table 2). Although the root dry weight was enhanced at the lower level of salinity for most of the clones, there was not statistically significant difference detected between the means of the different treatments (Table 2). Grass Visual Quality Any level of salinity stress had a significant adverse effect on the grass visual quality (Table 3). Quality scores for various clones ranged from 9.7 to 2.6 at different salinity stress levels. At EC 20 dS m-1, quality scores ranged from 5.1 to 9.7 (Table 3) throughout the entire test. As shown in Table 3, all clonal entries had good quality and full maintenance of green tissue retention at EC 6 dS m-1 at the end of the trial. After 10 weeks growth at EC 34 dS m-1 (salinity level equal to that of sea level salinity), entries 239 and 240 were the only clones to have quality ratings of 6 (acceptable quality, on the scale of 1 - 10) or greater (Table 3). These two clones represented the best quality clones at EC 34 dS m-1 at the end of the test. At EC 48 dS m-1, no entries produced an acceptable plant quality (scores of 6 or higher). Most clones decreased in (final) quality as EC increased from EC 6 to EC 48 dS m-1, but the entries 239 and 240 showed a more of typical halophytic response, having an increase in quality at EC 20 dS m-1 over that observed at EC 6 dS m-1 (Table 3). Table 3. Saltgrass visual quality under salinity stress Grass ID General 6 quality* 20 at 34 EC 48 A37 8.0cde** 5.1f 3.3g 2.6e A49 7.7def 6.4d 4.3ef 2.8e A50 8.6abc 7.2bc 5.0cd 4.0bc A60 8.2bcd 5.5ef 3.9fg 3.5cd 72 9.0a 7.4bc 5.9b 4.8a A86 8.5abc 6.7cd 5.7b 3.9bc A107 7.5def 5.9def 5.4bc 4.4ab A126 6.7g 5.3f 4.6de 3.9bc A128 7.1fg 6.2de 5.0cd 3.0de A138 8.6abc 7.9b 5.4bc 4.2ab 239 8.9ab 9.3a 6.6a 4.2ab 240 9.2a 9.7a 7.1a 2.8e *The quality values are the means of 3 replications of each treatment and 10 weekly evaluations. **The values followed by the same letters in each column are not statistically significant at the 0.05 probability level. Salt Tolerance Ranking of the Various Clones of Saltgrass Salinity tolerance ranking of the various saltgrass clones used in this study based on shoot DM weight, root DM weight, grass visual quality, or overall ranking considering all the study parameters together, are presented in Table 4. Although there are some minor differences in salt tolerance ranking of the clones when compared based on shoot DM weight, root DM weight, or grass visual quality, the overall ranking is the best representation of the salinity tolerance of the various tested clones. Considering all the study parameters together, there was a wide range of salinity tolerance found among the 12 saltgrass clones. The 240 and 239 clones were the most salt tolerant clones (especially, up to EC of 34 dS m-1) followed by A128, 72, A138. These were closely followed by A50, A86, and A49 in salinity tolerance. A49 clone laid between this and the last group in regards to salinity tolerance. A60, A107, A37, and A126 were among the lowest salinity tolerant grasses which the A126 was the least tolerant clone. Table 4. Salt tolerance ranking of Saltgrass based on shoot weight, root weight, or grass visual quality Tolerance Salt Shoot wt. tolerance Root wt. based Quality on Overall High 240a* A128a 240a 240a A128ab 240ab 239a 239a 239ab 239ab 72ab A128ab 72ab A50ab A138ab 72ab A86ab A60abc A50abc A138ab A138abc A138abc A86bc A50b A50bc A49bc A60bcd A86b A49bc A86bc A49cde A49bc A107cd A37cd A128de A60cd A37cd 72cd A107de A107cd A126d A107cd A37de A37cd Low A60d A126d A126e A126d *The clones followed by the same letters in each column are not statistically significant at the 0.05 probability level. Overall, the results of the shoot and the root dry mass and the visual grass quality showed that the maintenance of green foliage and tolerance under saline hydroponic conditions are under physiological conditions/adjustments that are not totally related to dry matter (DM) production in shoots and roots. This was corroborated by the results that clones which maintained the highest quality under EC 34 dS m-1 exhibited either a large increase in root mass (i.e., clone 239), or only a small increase of the root mass (i.e., clone 240) produced at EC 6 dS m-1. Likewise, clone A138 produced a large increase of its EC 6 dS m-1 root mass at the highest EC level of 48 dS m-1. However, it could not maintain green foliage at 10 weeks of exposure to this high EC. The same was true for shoot DM production that occurred in a more narrow range of values than did root DM production. In short, saltgrass shoot DM weight decreased linearly with increased salinity levels for all clones. For most clones, there was no difference among the root DM of the grass at different salinity levels. Visual quality of the grass followed the same pattern as the shoot DM weight. It decreased linearly with increased salinity levels for all clones. Clones differed greatly in their maintenance of green color retention (quality) as EC levels (salinity) increased. Two clones which produced acceptable quality at the EC level of 34 dS m-1 were clones 239 and 240. No clones could maintain adequate quality color at EC level of 48 dS m-1 after 10 weeks of exposure at this EC level. The difference in salinity tolerance level among the clones was significant. The grasses were separated in several groups with different degrees of salt tolerance. Considering all the study parameters together, there was a wide range of salinity tolerance found among the 12 saltgrass clones. The 240 and 239 clones were the most salt tolerant clones (especially, up to EC of 34 dS m-1) followed by A128, 72, and A138. These were closely followed by A50, A86, and A49 in salinity tolerance. A49 clone laid between this and the last group in regards to salinity tolerance. A60, A107, A37, and A126 were among the lowest salinity tolerant grasses which the A126 was the least tolerant clone. Conclusions In terms of salinity tolerance (quality), green foliage retention was empirically the best assessment of the clonal response to increased salinity. For large scale screening of saltgrass germplasm, the maintenance of green tissue at a specific EC level would seem to be adequate as a simple selection method for salinity tolerance. Shoot and root lengths and dry weights decreased with increased salinity stress. However, shoots were more severely affected by salinity stress than the roots. Grass visual quality was significantly affected (lower quality) as the salinity levels of the culture solutions increased. Overall, the results of this investigation indicate that saltgrass is a very high salinity tolerant species, and the results further suggest that this grass growing even under poor soil conditions (salt-affected desert soils) can be a suitable and beneficial plant species for growth and production in arid regions, and still show a favorable growth. Acknowledgments This study was financially supported by a grant from the United States Golf Association (USGA). References Enberg A, Wu L. 1995. Selenium assimilation and differential response to elevated sulfate and chloride salt concentrations in two saltgrass ecotypes. Ecotoxicology and Environmental Safety, 32(2):71‑178. Gessler N, Pessarakli M. 2009. Growth Responses and Nitrogen Uptake of Saltgrass under Salinity Stress. Turfgrass Landscape and Urban IPM Research Summary 2009, Cooperative Extension, Agricultural Experiment Station, The University of Arizona, Tucson, AZ, USA, United States Department of Agriculture (USDA), Publication AZ1487, Series P-155, pp 32-38. Gould FW. 1993. Grasses of the Southwestern United States. 6th Edition. The University of Arizona Press, Tucson, AZ, USA. Hoagland DF, Arnon DI. 1950. The Water Culture Method for Growing Plants Without Soil. California Agriculture Experiment Station, Circulation, 347 (Rev.). Kopec DM, Adams A, Bourn C, Gilbert J.J, Marcum K, Pessarakli M. 2001a. Field Performance of Selected Mowed Distichlis Clones, United States Golf Association (USGA) Research Report #3. Turfgrass Landscape and Urban IPM Research Summary 2001, Cooperative Extension Agriculture Experiment Station, The University of Arizona, Tucson, AZ, USA, United States Department of Agriculture (USDA), Publication AZ1246 Series P-126, pp. 295-304. Kopec DM, Adams A, Bourn C, Gilbert JJ, Marcum K, Pessarakli M. 2001b. Field Performance of Selected Mowed Distichlis Clones, United States Golf Association (USGA) Research Report #4. Turfgrass Landscape and Urban IPM Research Summary 2001, Cooperative Extension Agriculture Experiment Station, The University of Arizona, Tucson, AZ, USA, United States Department of Agriculture (USDA), Publication AZ1246 Series P-126, pp. 305-312. Kopec DM, Marcum K, Pessarakli M. 2000. Collection and Evaluation of Diverse Geographical Accessions of Distichlis for Turf-Type Growth Habit, Salinity and Drought Tolerance. Report #2, Cooperative Extension Agriculture Experiment Station Service, The University of Arizona, Tucson, AZ, USA, 11p. Kopec DM, Nolan S, Brown PW, Pessarakli M. 2006. Water and Turfgrass in the Arid Southwest: Water Use Rates of Tifway 419 Bermudagrass, SeaIsle 1, Seashore Paspalum, and Inland Saltgrass. United States Golf Association (USGA) Green Section Record, A Publication of Turfgrass Management, November-December 2006 Issue (6):12-14. Marcum KB, Kopec DM, Pessarakli M. 2001. Salinity Tolerance of 17 Turf-type Saltgrass (Distichlis spicata) Accessions. International Turfgrass Research Conference, July 15-21, 2001, Toronto, Ontario, Canada. Marcum KB, Pessarakli M, Kopec DM. 2005. Relative salinity tolerance of 21 turf-type desert saltgrasses compared to bermudagrass. HortScience 40(3): 827-829. www.ashs.org Miller Deborah L, Smeins FE, James W. Webb. 1998. Response of a Texas Distichlis spicata coastal marsh following lesser snow goose herbivory. Aquatic Botany, 61(4):301‑307. Miyamoto S, Glenn EP, Olsen MW. 1996. Growth, water use and salt uptake of four halophytes irrigated with highly saline water. Journal of Arid Environment, 32(2):141‑159. O’Leary J.W, Glenn E.P. 1994. Global distribution and potential for halophytes. In: Halophytes as a Resource for Livestock and for Rehabilitation of Degraded Lands (V.R. Squires and A.T. Ayoub, Eds.). pp7-19. Kluwer Acad. Publ., Dordrecht. Pessarakli M. 2005a. Supergrass: Drought-tolerant turf might be adaptable for golf course use. Golfweek’s SuperNews Magazine, November 16, 2005, p 21 and cover page. http://www.supernewsmag.com/news/golfweek/ supernews/20051116/ p21. asp?st=p21_s1.htm Pessarakli M. 2005b. Gardener’s delight: Low-maintenance grass. Tucson Citizen, Arizona, Newspaper Article, September 15, 2005, Tucson, AZ, USA. Gardener'sdelight:Low-maintenancegrasshttp://www.tucsoncitizen. com/ Pessarakli M. 2007. Saltgrass (Distichlis spicata), a Potential Future Turfgrass Species with Minimum Maintenance/Management Cultural Practices. In: Handbook of Turfgrass Management and Physiology (M. Pessarakli, Ed.), pp. 603-615, CRC Press, Taylor and Francis Publishing Company, Florida. Pessarakli M. 2008. Nitrogen Nutrition of Distichlis (Saltgrass) under Normal and Salinity Stress Conditions Using 15N. Turfgrass and Environment, United States Golf Association (USGA), p. 70. Pessarakli M, Gessler N, Kopec DM. 2008. Growth Responses of Saltgrass (Distichlis spicata) under Sodium Chloride (NaCl) Salinity Stress. United States Golf Association (USGA) Turfgrass and Environmental Research Online, October 15, 2008, 7(20):1-7. http://turf.lib.msu.edu/tero/ v02/n14.pdf Pessarakli M, Harivandi MA, Kopec DM, Ray DT. 2012. Growth Responses and Nitrogen Uptake by Saltgrass (Distichlis spicata L.), a Halophytic Plant Species, under Salt Stress, Using the 15N Technique. International Journal of Agronomy, Volume 2012, Article ID 896971, 9 pages, doi:10.1155/2012/896971. Pessarakli M, Kopec DM. 2005. Responses of Twelve Inland Saltgrass Accessions to Salt Stress. United States Golf Association (USGA) Turfgrass and Environmental Research Online 4(20):1-5. http://turf.lib.msu.edu/tero/ v02/ n14.pdf Pessarakli M, Kopec DM. 2011. Responses of Various Saltgrass (Distichlis spicata) Clones to Drought Stress at Different Mowing Heights. Journal of Food, Agriculture, and Environment (JFAE), Vol. 9(3 and 4):665-668. Pessarakli M, Kopec DM. 2006. Interactive Effects of Salinity and Mowing Heights on the Growth of Various Inland Saltgrass Clones. Turfgrass and Environment, United States Golf Association (USGA), pp. 83-84. Pessarakli M, Kopec DM. 2008a. Establishment of Three Warm-Season Grasses under Salinity Stress. Acta HortScience, International Society of Horticultural Science (ISHS), Vol. 783:29-37. Pessarakli M, Kopec DM. 2008b. Growth Response of Various Saltgrass (Distichlis spicata) Clones to Combined Effects of Drought and Mowing Heights. United States Golf Association (USGA) Turfgrass and Environmental Research Online, January 1, 2008, 7(1):1-4. http://turf.lib. msu.edu/tero/v02/n14.pdf Pessarakli M, Kopec DM. 2010. Growth Responses and Nitrogen Uptake of Saltgrass (Distichlis spicata), a True Halophyte, under Salinity Stress Conditions using 15N Technique. Proceedings of the International Conference on Management of Soils and Ground Water Salinization in Arid Regions, Vol. 2, 1-11, Muscat, Sultanate of Oman. Pessarakli M, Kopec DM, Koski AJ. 2003. Establishment of Warm-Season Grasses under Salinity Stress. American Society of Agronomy-Crop Science Society of America-Soil Science Society of America (ASA-CSSA-SSSA) Annual Meetings, Nov. 2-6, 2003, Denver, CO. Pessarakli M, Kopec DM, Ray DT. 2011a. Growth Responses of Various Saltgrass (Distichlis spicata) Clones Under Salt Stress Conditions. Journal of Food, Agriculture, and Environment (JFAE), Vol. 9(3 and4):660-664. Pessarakli M, Marcum KB, Emam Y. 2011b. Relative droughttolerance of various desert saltgrass (Distichlis spicata) genotypes. Journal of Food, Agriculture, and Environment (JFAE), Vol. 9(1):474-478. Pessarakli M, Marcum KB. 2000. Growth Responses and Nitrogen-15 Absorption of Distichlis under Sodium Chloride Stress. American Society of Agronomy-Crop Science Society of America-Soil Science Society of America (ASA-CSSA-SSSA) Annual Meetings, Nov. 5-9, 2000, Minneapolis, Minnesota. Pessarakli M, Marcum KB, Kopec DM. 2001a. Drought Tolerance of Twenty one Saltgrass (Distichlis) Accessions Compared to Bermudagrass. Turfgrass Landscape and Urban IPM Research Summary 2001, Cooperative Extension, Agricultural Experiment Station, The University of Arizona, Tucson, AZ, USA, United States Department of Agriculture (USDA), Publication AZ1246 Series P-126, pp. 65-69. Pessarakli M, Marcum KB, Kopec DM. 2001b. Drought tolerance of turf- type inland saltgrasses and bermudagrass. American Society of Agronomy-Crop Science Society of America-Soil Science Society of America (ASA-CSSA-SSSA) Annual Meetings, Oct. 27 - Nov 2, 2001, Charlotte, North Carolina, Agronomy Abstract, C05-pessarakli130005-P. Pessarakli M, Marcum KB, Kopec DM. 2001c. Growth Responses of Desert Saltgrass under Salt Stress. Turfgrass Landscape and Urban IPM Research Summary 2001, Cooperative Extension, Agricultural Experiment Station, The University of Arizona, Tucson, AZ, USA, United States Department of Agriculture (USDA), Publication AZ1246 Series P-126, pp. 70-73. Pessarakli M, Marcum KB, Kopec DM. 2005. Growth responses and nitrogen-15 absorption of desert saltgrass under salt stress. Journal of Plant Nutrition, 28(8):1441-1452. www.tandf.co.uk/journals/titles/01904167.asp Pessarakli M, Tucker TC. 1985. Uptake of Nitrogen-15 by cotton under salt stress. Soil Science Society of America Journal, 49:149-152. Pessarakli M, Tucker TC. 1988. Dry matter yield and nitrogen-15 uptake by tomatoes under sodium chloride stress. Soil Science Society of America Journal, 52:698-700. Rossi AM, Brodbeck BV, Strong DR.1996. Response of xylem‑feeding leafhopper to host plant species and plant quality. Journal of Chemical Ecology, 22(4):653‑671. Sagi M, Savidov NA, L’vov NP, Lips SH. 1997. Nitrate reductase and molybdenum cofactor in annual ryegrass as affected by salinity and nitrogen source. Physiologia Plantanum, 99:546-553. SAS Institute, Inc. 1991. SAS/STAT User’s guide. SAS Inst., Inc., Cary, NC. Sigua GC, Hudnall WH. 1991. Gypsum and water management interactions for revegetation and productivity improvement of brackish marsh in Louisiana. Communications in Soil Science and Plant Analysis, 22(15/16):1721‑ 1739. Sowa S, Towill LE. 1991. Effects of nitrous oxide on mitochondrial and cell respiration and growth in Distichlis spicata suspension cultures. Plant‑Cell, Tissue, and Organ Culture (Netherlands), 27(2):197‑201. White RH, Engelke MC, Morton SJ, Ruemmele BA. 1992. Competitive turgor maintenance in tall fescue. Crop Science Journal, 32:251-256.
