Conseguences of soil crude oil pollution on some wood properties of olive trees Consequences of Soil Crude Oil Pollution on Some Wood Properties of Olive Trees Hassan H. Ali Basim A. Abd Ali Natural History Research Center and Museum / Baghdad University Received in : 9/1/2012 , Accepted in : 19/5/2013 Abstract To enlighten the extent of crude oil pollution effects on some anatomical characteristics of olive plant (Olea europaea ). Two years - old seedlings were chosen to grow under 5 levels of pollution (0.0, 0.5, 1.0, 2.0, and 3.0, liter/ plant). The experiment has been conducted in the experimental field of Natural History Research Center and Museum, University of Baghdad. It was designed as CRD experiment. Testing wood specimens were prepared after 2.5 years of growth. Fiber length, width, wall thickness, and wood specific gravity were measured. Results showed that olive plants could not resist the highest level ( 3 liters / plant ) of pollution .Fiber length was the most affected property by treatment. All fiber dimensions were decreased with the increase of pollution level. The reduction was unsystematic. 12% of the fiber length was reduced as a result of pollution. Wood specific gravity of polluted plants showed few higher values than that of control. Lower parts of stem seemed to be more affected, that may be because these parts are fare away from crown ( the source of oxen ). Keywords: olive, wood, soil, pollution, properties, crude, oil. 1 | Biology @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÚÓ‘Ój�n€a@Î@Úœäñ€a@‚Ï‹»‹€@·rÓ:a@Âig@Ú‹©@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@Ü‹1a27@@ÖÜ»€a@I1@‚b«@H2014 Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (1) 2014 Introduction The continuous growth of environmental pollution and anthropological disturbances to ecosystem has made the study of abiotic stress responses in plant become increasingly more important in agriculture, forest management , and ecosystem restoration strategies (1). Crude oil pollution is perhaps the most publicly recognized as serious pollutant despite much of the world depends on the production, trade, or manufacturing of oil. Although oil hydrocarbons are common pollutants and their biodegradation is the subject of numerous studies, information on their toxicity to the plant in the soil is limited. The reaction of some plants after the contamination of ground and water with oil products was studied by Petukhov et.al.( 2 ). They discussed the negative effects of oil contamination on seed germination, reduction of the total biomass and the length of the roots . The presence of petroleum in the soil affects its diversity, canopy and productivity. Little is known about the chronic effect of oil pollution ( 3 ). Michel et. al. ( 4 , 5 ) stated that petroleum constitutes a pollutant that can persist in the environment for a long period until the vegetation recovers completely , and its persistence can be explained by the slow biodegradation of hydrocarbons . According to Green et al . (6) , a variety of reports , patents and scientific papers have addressed the problems of fuel contamination in soil , including chemical characterization and treatment , bioremediation by bacteria metabolism and the impact on biological organisms in the contamination soil . The poisoning mechanism and its dose – response are the biggest concern for toxicologists. The inhibition of germination and the reduction of plant growth as well as its death are indication of the toxicity of hydrocarbons ( 7 ) . The study of plant behavior in petroleum contamination soils allows the identification and selection of oil – pollution – indicating species . Petuchov et. al., ( 2 ) recommended that tested species could be used as test organisms in analyzing the toxicity of this pollutant in soil and water. Comparison of the Podocarpus lambertii trees exposed to petroleum with the control set , showed that the length , diameter and cell wall width of the tracheids of the polluted trees were smaller than that of control ( 8 ) . Olive tree ( Olea europaea Linn )was introduced to Iraq since a long time ago and extensively cultivated in different parts of Iraq ( 9 ) especially in the upper parts of the country. The tree is considered as a tolerant for drought , and for nitrogen deficiency (10). Recently , Iraqi Ministry of Agriculture considers the tree as one of the important economic plants and adopted many projects to expand planting areas and encouraged farmers for planting the tree in their private plantation . Although oil is the main product of olive tree, it is considered as a good source for high quality timbers .Wood is the result of a biological process and grows under a wide range of genetic and environmental influences. Environmental conditions play an important role in tree growth and wood characteristic . Though , any factor having an influence on one or more of these conditions could have an effect on the growth and wood properties . Thus the present study intends to focus on the effects of crude oil pollution on some of olive wood properties . Materials and Methods Olive seedlings nearly two years old were brought from local nursery in Baghdad and planted at experimental area of Natural History Research Center . Six months later, the uniform and nearly equal lengths seedling were chosen and exposed to five levels of crude oil pollution. The experiment was designed as a complete randomized experiment with 5 levels, and 4 replications. Amounts of pollution for each level were as follows ; 0, 0.5, 1.0, 2.0 and 3 liter of Basra light crude oil ( obtained from Ministry of Oil ) for L0 , L1, L 2 , L3 2 | Biology @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÚÓ‘Ój�n€a@Î@Úœäñ€a@‚Ï‹»‹€@·rÓ:a@Âig@Ú‹©@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@Ü‹1a27@@ÖÜ»€a@I1@‚b«@H2014 Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (1) 2014 and L4 respectively .Accordingly, measured quantities of crude oil was poured around selected seedling . Then, uniform irrigation processes were applied to all experimental units . Plants were left to grow for a period of thirty months. After that, the developed shrubs were harvested from the ground . Two disks from the main stem were cut, the first from the base , the second from the uppermost where it was possible to obtain a disc with sufficient diameter. Each disc was divided into two equal parts, one of them was further divided into small sticks for maceration, the other was used for preparing samples of specific gravity. Maceration has done according to ( 11). 40 readings were taken for any of fiber length, fiber diameter, lumen diameter and wall thickness for each level of experimental combinations. Specific gravity was measured for the upper and lower parts of stem separately, and it was determined by immersion method where each mean value represented a mean of 4 measurements. The experiment was designed and conduced by using complete randomized design ( C.R.D ) , and the treatments were replicated four times . The results were statistically analyzed by using Statistica program ( 99 Edition ) . Results and discussion The experiment showed that olive plants of two years old could not survive after pollution by the highest level L4 ( 3 liters / plant), therefore they were excluded from statistical analysis, and the levels of pollution became 4 ( L0, L1, L2, and L3 ) only. Fiber length was the only property of fiber dimensions that significantly affected ( p