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Physiological effects of high temperature treatments on leaves of olive cv. gemlik Article · January 2012
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Plant Archives Vol. 12 No. 1, 2012 pp. 521-525
ISSN 0972-5210
PHYSIOLOGICAL EFFECTS OF HIGH TEMPERATURE TREATMENTS ON LEAVES OF OLIVE cv. GEMLIK Asuman Cansev Department of Horticulture, Faculty of Agriculture, Uludag University, 16059, Nilufer, Bursa, Turkey. E-mail:
[email protected]
Abstract Temperature is one of the most important environmental factors for survival of plants. Each plant has an optimum temperature for development and growth. However, as in most plant species, olive tree may be subjected to different temperatures distinct from its ecological needs. This study was conducted to investigate the effects of high temperatures which are likely to be observed in the future due to global climate changes on olive cv. Gemlik leaves. For this purpose, one-year shoots of 25 yearold olive trees were obtained at the end of May and the leaves were subjected to high temperature treatments in water bath at 40, 45, 50, 55, 60 and 65°C with gradual increments every 3 hours. The leaves were then analyzed for cell membrane injury, lipid peroxidation, loss of turgidity, leaf relative water content and chlorophyll content. Results revealed that membrane damage and lipid peroxidation were increased significantly starting at 50 oC, while leaf relative water content and chlorophyll content decreased. Therefore, it can be concluded that high temperature stress affects the growth and development of olive tree by damaging cellular membranes in leaves, reducing water content and inhibiting photosynthesis particularly when the temperature is above 50 oC in May in northwest of Turkey. Key words : Olive, high temperature stress, physiological changes.
Introduction The olive (Olea europaea L.) is an important plant for its high economic value especially for countries in Mediterranean region (Pereira et al., 2007). Due to the geographic location of Turkey, the olive is planted in almost all regions of our country, most of which are under the effect of Mediterranean climate. Although, it is generally accepted that the olive can easily adapt to high temperatures, evidence suggests that it has lower yields at temperatures out of its tolerance range. Photosynthesis is reduced and vegetative growth is stopped when maximum temperature exceeds 35°C and 40°C, respectively (Eris and Barut, 2000). Recently, various global climate changes, particularly global warming, have been observed due to industrialization, uncontrolled urbanization and population increases and senseless agricultural practice. Turkey is predicted to be one of the most affected countries from global warming (Eris et al., 2008). In addition, climate zones are suggested to shift hundreds of kilometers from the equator towards poles resulting in the inclusion of Turkey in the hot and droughty climate zone that presently affects Middle East and North Africa (Turkes, 2003). A
possible climate change is likely to affect the South East and Central regions of our country which are under desertification threat, as well as the semi-humidified Aegean and Mediterranean regions which are devoid of adequate water supplies (Ozturk, 2002). Such climate instability negatively affects physiological processes of the plants and hence, the yield, by causing abiotic stress on agricultural products. Because global warming is believed to cause a variety of heat-related stress responses in plants that may alter their ability to survive, the present study was conducted to help quantify plant responses to global warming. This study aimed to determine the physiological responses of the olive plant under high temperatures in May in Bursa, Turkey. Results revealed that high temperature stress affects the growth and development of olive tree negatively by damaging cellular membranes, reducing water content and inhibiting photosynthesis in leaves. Hence, the present study provides evidence with regard to the possible fate of the olive tree, one of the most important agricultural and economical values in Bursa, under high temperatures that might be faced in the future due to global climate changes.
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Materials and Methods Plant material and high temperature tests One-year shoots of olive cv. Gemlik was used in the study. The samples were obtained in May from an orchard containing 25 year-old olive trees in Gorukle town which is close to Uludag University, Bursa, Turkey (latitude: 29° 04' E, longitude: 40°39' N). Average temperatures in May were 17.4 °C (3.4–34.2 °C). High temperatures were generated artificially by gradually increasing the temperature as described previously Arora et al. (1998) with some modifications. Briefly, leaves obtained from one-year shoots were collected into pyrex tubes with caps closed and placed into water bath. After a 30-min habituation of the samplecontaining tubes in water bath adjusted to 35ºC, the water temperature was inclined to 40ºC in half an hour. Samples were then subjected to 40, 45, 50, 55, 60 and 65°C temperatures with gradual increments every 3 hours. Samples that were obtained at each treatment temperature were analyzed for membrane injury, high temperature tolerance, lipid peroxidation, water content and loss of turgidity, and chlorophyll content. Rate of injury Rate of cell membrane injury was determined by ion leakage tests as previously described by Arora et al. (1992). Briefly, leaf disks of 1 cm diameter from each treatment group were placed into test tubes containing 20 ml of deionized water. The samples were then subjected to vacuum infiltrated at -0.15 MPa for 5 min to allow uniform diffusion electrolyte and incubated on a shaker at 250 rpm at room temperature (24 ± 1oC) for 4 hours before electrical conductivity of each sample was measured by a conductivity meter (WTW TetraCon 325 model, InoLab Cond Level 1, Weilheim, Germany). Leaf discs were killed in the same solution by autoclaving and total conductivity was measured at room temperature. Electrolyte leakage was expressed as the percentage of total ions present in the tissue. Percent injury at each temperature was calculated from ion leakage data using the equation (Arora et al., 1992): % injury = [(%L(t)-%L(c)) / (100-%L(c))] x 100, where %L(t) and %L(c) are percent ion leakage data for the treatments and control samples, respectively. All measurements were replicated three times. High temperature tolerance (LT50) High temperature tolerance (LT50) was defined as the temperature causing half-maximal % injury calculated as mid-point between maximum injury and control.
Lipid peroxidation Lipid peroxidation was determined by measuring malonedialdehyde (MDA) content of leaves as described previously by Rajinder et al. (1981). Briefly, 0.5 g of leaf sample was homogenized in 0.1% TCA (trichloroacetic acid) and centrifuged at 10.000 x g for 5 min. An aliquot (250 µl) of the supernatant was then transferred to another tube containing 1 ml of 20% (w/v) TCA and 0.5% (w/v) TBA (thiobarbituric acid). The mixture was incubated at 100°C for 30 min and the reaction was stopped by placing the reaction tubes in an ice-water bath. The samples were then centrifuged at 10,000 × g for 10 min. The absorbance of the supernatant was read at 532 and 600 nm by a spectrophotometer (Beckmann, Coulter Inc., Fullerton, CA). MDA content was expressed as nmol/gTA. Leaf relative water content and loss of turgidity Leaf relative water content (RWC) and loss of turgidity were analyzed by a previously-described method by Gulen and Eris (2003). Leaf disks of 1 cm diameter were weighed at three different states; fresh state, turgor state after incubating in deionized water for 4 hours, and dry state after drying at 800C for 48 hours. RWC and loss of turgidity was measured as follows respectively; RWC = [(fresh weight-oven dry weight)/ (turgid weight-oven dry weight)] × 100 Loss of turgidity = (turgid weight - fresh weight)/ turgid weight × 100 Chlorophyll content Changes in chlorophyll content of olive leaves were analyzed spectrophotometrically as described by Moran and Porath (1980). Leaf samples subjected to dimethylformamide (DMF) extraction were incubated at +4ºC for 72 hours. The absorbance of supernatants were measured at 652 nm by a spectrophotometer. Data were expressed as mg/g fresh weight.
Results and Discussion Fig. 1 shows that high temperature treatments cause significant injury on olive leaves. Although the rate of injury was minimal at 40 and 45oC treatments, it was greater than 50% at 50 oC treatment with a linear increment at higher temperatures. High temperature tolerance point is a good means of the ability of the plant to survive at high temperatures. High temperature tolerance (LT50) was determined by a method which is based on leakage of ions out of the injured cell membranes. Data show that LT50 value of leaves of olive cv. Gemlik is 49.5oC. When compared with the previously-reported (Mancuso and Azzarello, 2002) LT50 values of leaves of
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Fig. 1 :Injury rates in leaves of olive cv. Gemlik with respect to exposure to high temperatures. Vertical curve indicates LT50 as 49.5oC. Fig. 2 : Changes of lipid peroxidation (MDA) in olive leaves cv. Gemlik with respect to exposure to high temperatures. C : Control (Samples not subjected to high temperature treatment). Vertical lines on bars represent ±SS of repetitions.
Fig. 3 : The effects on leaf water relative content (RWC) of olive leaves cv. Gemlik with respect to exposure to high temperatures. C : Control (Samples not subjected to high temperature treatment). Vertical lines on bars represent ±SS of repetitions.
olives cvs. Leccino, Frantoio, Maurino, Pendolino, Moraiolo, Carbona, Coratina, Diana, Simjaca and Urano as 50.34, 50.50, 49.05, 48.10, 48.38, 50.70, 50.74, 49.79, 46.75 and 46.83oC, respectively, it can be suggested that olive cv. Gemlik has a moderate tolerance against high temperatures.
Fig. 4 : The effects on loss of turgidity of olive leaves cv. Gemlik with respect to exposure to high temperatures. C: Control (Samples not subjected to high temperature treatment). Vertical lines on bars represent ±SS of repetitions.
In the present study, MDA content increased significantly at 50oC treatment and showed parallel increases with increasing rate of injury (fig. 2). Free radicals that are generated under stress conditions in plants cause injury in cell membranes by lipid peroxidation. Malonedialdehyde (MDA) is a metabolite which is generated by peroxidation of unsaturated fatty acids in
membrane phospholipids, and it is used as a marker for membrane breakdown (Halliwell and Gutteridge, 1989). In good accord with the present finding, high temperature stress was shown to enhance MDA content in leaves and roots of Agrostis palustris Huds (Liu and Huang, 2000) suggesting the onset of an oxidative injury due to high temperatures.
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temperature can damage components of leaf photosynthesis during the vegetative state leading to reduced carbon dioxide assimilation rates (Mancuso and Azzarello, 2002). Therefore, the present data with regard to reduced chlorophyll content by high temperature treatment are in agreement with those reported in previous studies.
Fig. 5 : The effects on chlorophyll content of olive leave cv. Gemlik with respect to exposure to high temperatures. C : Control (Samples not subjected to high temperature treatment). Vertical lines on bars represent ±SS of repetitions.
Osmoregulation of plant cells is an important mechanism under stress conditions caused by heat, cold, drought and salinity (Hasthanasombut et al., 2011). The maintenance of turgor has been reported to be essential for keeping a normal cell activity and contribute to growth (Farouk, 2011). Therefore, leaf relative water content and turgor state could serve as indicators of growth and development. High temperatures lead to a decrease in leaf water content and loss of turgidity by enhancing transpiration (Turkes, 2003; Yamasaki and Dillenburg, 1999). Data from the present study revealed that leaf relative water content was stable at temperatures up to 45oC, while it decreased significantly at 50oC; the leaf water content fell down to 50% of its basal values when the temperature was increased to 55oC (fig. 3). Similar observations were made with regard to loss of turgidity (fig. 4). Although the olive is considered to have tolerance to high temperatures during summer, the present study shows that chronic subjection of olive tree to high temperatures exceeding 50oC during spring causes significant loss of leaf water content and turgor leading to disrupt normal physiological processes. Although leaf chlorophyll content was not affected by high temperatures up to 45oC, it started decreasing significantly with increasing temperatures from 50oC ( S, ekil 5). In good accord, Jiang and Huang (2001) showed that leaf relative water content and chlorophyll content were decreased by high temperature treatments in grass, suggesting damage of the photosynthetic reaction centers (Bowler et al., 1992). This suggestion is further supported by previous studies which demonstrated that high
In conclusion, high temperature stress disrupts the growth and development of olive tree by damaging cellular membranes in leaves, reducing water content and inhibiting photosynthesis particularly when the temperature is above 50oC May in North West of Turkey. Although to date low temperature, as opposed to high temperature, has been considered a limiting factor in olive cultivation (Eris et al., 2007; Cansev et al., 2009; Gulen et al., 2009 and Cansev et al., 2011), high temperature stress must as well be taken into account as a risk factor due to global climate changes. It might therefore be suggested that higher latitudes may serve as more suitable regions for olive cultivation in the future, while failure of the olive to adapt to high temperatures may generate a considerable risk for its survival and distribution on the earth. Hence, further physiological and molecular biological studies are required for understanding the response of the olive tree to high temperatures and the mechanism by which it shows adaptation under such conditions. In addition, strategies are needed to enhance the ability of the olive to adapt high temperature stress.
References Arora, R, M. E. Wisniewski and R. Scorza (1992). Cold acclimation in genetically related (Sibling) dedicious and evergreen peach (Prunus persica [L.] Batsch). I. seasonal changes in cold hardiness and polypeptides of bark and xylem tissues. Plant Physiol., 99 : 1562-1568. Arora, R., S. Dharmalingam, S. Pitchay and B. C. Bearce (1998). Water-stress-induced heat tolerance in geranium leaf tissues : a possible linkage through stress proteins? Physiologia Plantarum, 103 : 24-34. Bowler, C., M. Van Montagu and D. Inze (1992). Superoxide dismutase and stress tolerance. Annu. Rev. Plant Physiol. Plant Mol. Biol., 43 : 83–116. Cansev, A., A. Eris and H. Gulen (2009). Cold-hardiness of olive (Olea europaea L.) cultivars in cold-acclimated and non-acclimated stages: seasonal alteration of antioxidative enzymes and dehydrin-like proteins. J Agricultural. Sci., 147 : 51-61. Cansev, A., H. Gulen and A. Eris (2011). The Activities of Catalase and Ascorbate Peroxidase in Olive (Olea europaea L. cv. ‘Gemlik’) under Low Temperature Stress. Hort. Environ. Biotechnol., 52(2) : 1-6.
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Gulen, H. and A. Eris (2003). Some Physiological Changes in Strawberry (Fragaria × ananassa cv. Camarosa ) Plants Under Heat Stress. J. Hort. Sci. Biotech., 78 : 894–898. Gulen, H., A. Cansev and A. Eris (2009). Cold-hardiness of olive (Olea europaea L.) cultivars in cold-acclimated and non-acclimated stages : Seasonal alteration of soluble sugars and phospholipids. Journal of Agricultural Science, 147 : 459-467. Eris, A. and E. Barut (2000). Temperate Fruit Crops- I. Uludag University, Faculty of Agriculture Text Book, Bursa Turkey, No : 6, 226p. Eri s, , A., H. Gulen, E. Barut and A. Cansev (2007). Annual patterns of total soluble sugars and proteins related to cold hardiness in olive (Olea europaea L. cv. Gemlik). J. Hort. Sci. Biotech., 82(4) : 597-604. Eri s, , A., H. Gülen, E. Turhan, N. Koksal and A. Cansev (2008). Global warming and viticulture (in Turkish: Küresel Isýnma ve Baðcýlýk). Symposium of Viniculture. 6-9 November 2008 Denizli, Turkey, Vol I: 51-57. Farouk, S. (2011). Osmotic adjustment in wheat flag leaf in relation to flag leaf area and grain yield per plant. Journal of Stress Physiology & Biochemistry, 7(2) : 117-138. Gülen, H. ve A. Eri s, (2003). Some Physiological changes in strawberry (Fragaria × ananassa Cv. Camarosa ) plants Under heat stress. J. Hort. Sci. Biotech., 78 : 894–898. Gulen, H., A. Cansev and A. Eris (2009). Cold-hardiness of olive (Olea europaea L.) cultivars in cold-acclimated and non-acclimated stages: Seasonal alteration of soluble sugars and phospholipids. Journal of Agricultural Science, 147 : 459-467. Halliwell, B. and J. M. C. Gutteridge (1989). Free Radical in Biology and Medicine, 2nd ed. Clarendon Press, London. Hasthanasombut, S., N. Paisarnwipatpong, K. Triwitayakorn, C. Kirdmanee and K. Supaibulwatana (2011). Expression of OsBADH1 gene in Indica rice (Oryza sativa L.) in correlation with salt, plasmolysis, temperature and light stresses. Plant Omics Journal, 4(7) : 400-407.
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Jiang, Y. and B. Huang (2001). Effects of calcium on antioxidant activities and water relations associated with heat tolerance in two cool season grasses. J. Exp. Bot., 52(355) : 341349. Liu, X. and B. Huang (2000). Heat stress injury in relation to membrane lipid peroxidation in creeping bentgrass. Crop Sci., 40 : 503–510. Mancuso, S. and E. Azzarello (2002). Heat tolerance in olive. Adv. Hort. Sci., 16(3-4) : 125-130. Moran, R. and D. Porath (1980). Chlorophyll determination in intact tissues using N,N-Dimethylformamide. Plant Physiol., 65(3) : 478–479. Ozturk, K. (2002). Global Climatic Changes and Their Probable Effect upon Turkey. (In Turkish: Küresel iklim deðiþikliði ve Türkiye’ye olasý etkileri). Journal of Gazi University Faculty of Education, 22(1) : 47-65. Pereira, A. P., I. C. F. R. Ferreira, F. Marcelino, P. Valentão, P. B. Andrade, R. Seabra, L. Estevinho, A. Bento and J. A. Pereira (2007). Phenolic Compounds and Antimicrobial Activity of Olive (Olea europaea L. Cv. Cobrançosa) Leaves. Molecules, 12 : 1153-1162 . Rajinder, S. D., P. P. Dhinsa and T. A. Thorpe (1981). Leaf Senescense : Corralated with Increased Levels of Membrane Permability and Lipid Peroxidation and Decreased Levels of Superoxide Dismutase and Catalase. J. Exp. Bot., 32(126) : 93–101. Turkes, M. (2003). Sustainable technological and behavioral options for reducing of greenhouse gas emissions. (in Turkish : Sera gazý salýnýmlarýnýn azaltýlmasý için sürdürülebilir teknolojik ve davranýþsal seçenekler). Fifth Congress of National Environmental Engineering, Ankara, Turkey, Vol I : 267-285. Yamasaki, S. and L. R. Dillenburg (1999). Measurements of leaf relative water content in Araucaria angustifolia. Revista Brasilleira de Fisiologia Vegetal, 11(2) : 69-75.
