Influence of Amf inoculation on growth, nutrient uptake, arsenic toxicity and chlorophyll content of eggplant grown in arsenic amended soil.
Arsenic is a ubiquitous metalloid that is introduced in to the environment from both anthropogenic and geochemical sources (Smith et al., 1998). In Bangladesh, arsenic contamination of groundwater is believed to cause arsenic-related disorders in 80% of the population (Alam et al., 2002; Das et al., 2004).
Arsenic can be introduced to food through plant uptake in soil contaminated by groundwater or irrigation water. In Bangladesh, the groundwater arsenic contamination problem is the worst in the world. High levels of As in groundwater are causing widespread poisoning in Bangladesh. Contaminated groundwater is also used for irrigation of paddy rice, and other agricultural crops.
Eggplant (Solanum melongena) belongs to the family Solanaceae is commonly used as a popular vegetable in Bangladesh. It grows well during winter in Bangladesh. Moreover, In Bangladesh, about 71205 acres of land was under eggplant cultivation and total production was about 222110 metric tons (BBS, 2007).
Arbuscular mycorrhiza (AM) fungi are vital components of nearly all terrestrial ecosystems, forming mutually beneficial (mutualistic) symbiosis with the roots of around 80% of vascular plants and often increasing phosphate (P) uptake and plant growth. Since the association is mutualistic, both organisms benefit from the association. A major function of these fungi is to increase the surface area of plant root systems, greatly facilitating uptake of soil water and nutrients, especially in harsh conditions. In particular AM fungi can greatly enhance the uptake of P[O.sub.4], as well as N[H.sub.4.sup.+], [K.sup.+], and N[O.sub.3.sup.-] (Marschner and Dell, 1994; Hayman, 1983). The positive role of the vesicular-arbuscular mycorrhizal (VAM) fungi in P uptake and plant growth response under P-deficient conditions has been well established for many agricultural systems (Mosse, 1973). Vesicular-arbuscular mycorrhizas are also important for N uptake to stimulate the growth and nutrition of plants and are of great ecological importance with regards to N-nutrition of plant, especially non-fining species (Barea, 1991). Arbuscular mycorrhizae increase plant productivity by increasing the rate of photosynthesis (Masri, 1997) and providing protection against toxic metals (Bonifacio et al., 1999).
As a chemical analogue of phosphate, As competes with P in the soil because both elements are taken up via the phosphate transport systems (Cao et al., 2003). On the other hand, phosphate may also have a direct effect on As speciation in soil and may enhance As phytoavailability (Melamed et al., 1995; Peryea and Kammereck, 1997).
Some studies have shown that higher plants that have adapted to As-polluted soils are generally associated with mycorrhizal fungi (Meharg and Cairney, 1999; Sharples et al., 2000a, b; Gonzalez et al., 2002). Recently it has been demonstrated that mycorrhizas and phosphate fertilizers can protect plants grown in Ascontaminated soils. The mechanisms proposed include the tolerance of higher plants to arsenate through down regulated arsenate/ phosphate transporters in the epidermis and root hairs (Meharg and Macnair, 1992), to reduce the uptake of As, and upregulated low affinity of phosphate transporters located in the membrane fraction of mycorrhizal roots (Harrison et al., 2002), to take up more P for better growth. Certain Arbuscular mycorrhiza (AM) fungi have been shown to provide host plants with some tolerance of toxic conditions; including high metal concentrations (Sharples et al., 2000a and b; Bradley et al., 1981, 1982).There is growing evidence that AM fungal infection can exert protective effects on host plants under conditions of trace element/metal/metalloid contamination. When considering the toxicity of arsenic to plants, the role of mycorrhizal associations must also be considered, as one of the principal roles of mycorrhizal fungi is phosphorus uptake (Smith and Read, 1997). This could potentially be a problem on arsenic contaminated substrates because of enhanced acquisition of arsenate. However, there is also growing evidence that mycorrhizal fungi may alleviate metal or metalloid toxicity to the host plant by acting as a barrier to uptake (Leyval et al., 1997). The underlying mechanism is thought to be the binding capacity of fungal hyphae which immobilize the metals in or near the roots and thus depresses translocation to the shoots (Bradley et al., 1981; Brown and Wilkins 1985). Saha (2008) reported that AMF inoculation increased plant growth parameters and decreased As toxicity of tomato, radish and garlic grown in As contaminated soil. The objectives of the present study were to assess the influence of AMF inoculation on growth and nutrient uptake by brinjal and /or the interaction of arsenic and mycorrhiza on different physical and chemical growth parameters of eggplant.
Materials and methods
Experimental site and experimental period
The poly bag experiment was carried out in the net house of Sher-e- Bangla agricultural University, Dhaka, Bangladesh during the period from March 2008 to July 2008. Soil was collected from the Agronomy field of Sher-e-Bangla Agricultural University campus from a depth of 5 to 10 inch. After collecting the soil, clods were broken and weeds, stones, gravels, roots and other unwanted materials were removed. Soil was prepared for the experiment containing 10 % sand and 90 % soil.
A survey program was conducted in the Agronomy field of Sher-e-Bangla Agricultural University in February 2008 to collect natural inoculum of Mycorrhiza. Root samples of different plants species growing under the natural condition in different places of the Agronomy field were collected for the observation of occurrence of Arbuscular Mycorrhizal fungi (AMF) association with the root systems. The roots of each species were stained according to Koske and Gemma (1989) with some modifications (Mridha et al., 1999). The root pieces were boiled in 2.5 % KOH solution for 30 minutes at 90[degrees]C temperatures. Later on, the root segments were washed in water for several times and acidified with 1% HCl solution for 24 hours. Heavily pigmented roots were bleached by 10% [H.sub.2][O.sub.2] for 20 to 60 minutes. Again, these segments were boiled for 30 minutes in 0.05% aniline blue at a temperature of 90[degrees]C. Subsequently the roots were destined at room temperature in acidic glycerol. Leucas aspara plant roots showed the highest percentage of infection of mycorrhiza among the plant species examined and it was collected along with the rhizosphere soil for inoculation.
Preparation of arsenic solution
For preparation of 1000 ppm 1 liter arsenic solution at first 4 g Sodium hydroxide was taken in a 100 ml measuring cylinder. Sodium hydroxide was diluted with distilled water and the volume of the cylinder rose up to the 100 ml mark. Then 1.32 g arsenic powder was taken in another 1000 ml measuring cylinder and dilute with Sodium hydroxide. 10% Hcl was added into the 1000 ml measuring cylinder to acidify the solution. At lasts the volume of the flask rise up to 1000 ml mark with distilled water.
Preparation of polybag and general inoculation technique
The polythene bags of 12"x10" size were used which has the capacity to fill 2 kg soil. Soil was sterilized by formaldehyde (0.05%) and used it as base soil. Soil was taken into the perforated seedling bags. At first 2/3rd portion of the seedling bags were filled with substratum. Then a layer of both inoculum i.e. root inoculum 25 g and soil inoculum 100 g, were placed in each treated bag. Five replications i.e., 5 for inoculated and 5 for non-inoculated polybags were prepared. Both 25 g roots and 100 g sterilized soil (rhizosphere) were used in non-inoculated bags to maintain the same nutrient status between the inoculated and non-inoculated bags. The inoculum layer of each bag was covered with a thin soil (substratum) layer of 2 cm below the surface on which seeds were sown. 35 polythene bags (7 x 5) were prepared for the study. Twenty seeds/ bag were sown.
Data were recorded on seedling emergence at 7, 10 and 15 days after sowing (DAS). Seedlings were harvested at 30, 45 and 60 days of sowing. In this case 3 seedlings bags from inoculated and 3 seedlings bags from non-inoculated were harvested randomly. At first polythene bags were removed very carefully with sharp knife. The roots were washed with tap water to remove the adhering soil. Shoots and roots were separated with the help of sharp scissors and were preserved after necessary processing for determining shoot mass and root mass. Shoots and roots were then dried in an oven for 72 hours at 70[degrees]C until the samples gave constant weight. Shoot fresh and dry weight (30 DAS, 45 DAS, 60 DAS), root fresh and dry weight (30 DAS, 45 DAS, 60 DAS), shoot and root length (30 DAS, 45 DAS, 60 DAS) were recorded.
Nutrient analysis of plant sample
Plant (shoot) samples were dried in oven at 70[degrees]C for 72 hours and then ground the samples and sufficient amount of sample for each treatment was kept in desiccators for chemical analysis. An amount of 0.5g of subsample was taken into a dry clean 100 ml Kjeldahl flask.10 ml of di-acid mixture (HN[O.sub.3], HCl[O.sub.4] in the ratio of 2:1) was added and kept for few minutes. Then, the flask was heated at a temperature rising slowly to 200[degrees]C. Heating was instantly stopped as soon as the dense white fumes of HCl[O.sub.4] occurred and after cooling, 6ml of 6N HCl were added. The content of the flask was boiled until they became clear and colorless. This digest was used for determining P, K and S. Phosphorus and Sulphur were determined with the help of a spectrophotometer, potassium was determined with the help of flame photometer and nitrogen was determined with the help of Micro-kjeldahl method.
Arsenic analysis of plant sample
Arsenic toxicity of plant was analyzed detected in the laboratory of Pharmacology Department, Bangladesh Agricultural University, Mymensingh with Hydride Generation Atomic Absorption Spectrophotometer (HGAAS; PG-990, PG Instruments Ltd. UK). Arsenic was detected by forming As[H.sub.3] at below [p.sup.H] 1.0 after the reaction of As with a solution of potassium borohydride (KB[H.sub.4]=53.94, BDH Chemicals Ltd., Poole England, UK.), sodium hydroxide (NaOH, M=40,000 g/mol, Merck KGaA, Darmstadt, Germany) and 10% HCl. In this test, standard was maintained as [As.sup.V] ranging from 0 to 12.5 [micro]g/L.
Reading was taken with the help of a computer connected to the HG-AAS by using manufacturer supplied 'AAwin software' (Atomic Absorption Spectrophotometer PC-Software). The reading of the tested sample was displayed on the computer monitor in a pre-customized Microsoft excel sheet provided by the AAWin software as numerical number with giving a peak of As concentration on the respective part of the software displayed sheet on the computer monitor. Readings of As concentrations of the samples were taken in ppb.
Chlorophyll extraction of plant sample
Chlorophyll extraction was done in the plant physiology Lab, Bangladesh Rice Research Institute (BRRI), Gazipur with the help of Spectrophotometer. 1 gram fresh plant samples (leaves) were cut into small pieces and inserted into test tubes. Then 100 ml (80%) acetone was added in air tight condition to avoid losses. The test tubes were kept for 24-48 hrs in normal temperature. Data was recorded by Spectrophotometer.
Total chlorophyll = Absorbance (chlorophyll a + chlorophyll b) x Correction Factor
In this experiment all data were analyzed in the computer using MSTAT package Program and mean difference was compared by DMRT.
Results and Discussion
Arsenic solution reduced seedling emergence of eggplant at 10 and 15 DAS in all the concentration tested (Table 1). But the seedling emergence is increased when mycorrhiza was inoculated in the arsenic amended soil. The highest seedling emergence was recorded under the treatment [T.sub.3] (100 ppm As+ mycorrhiza) in compare to control. The influence of AMF inoculation on shoot height and root length of eggplant, grown in soil amended with different concentrations of arsenic solution is shown in Table 2. The data were varied significantly at different arsenic concentrations tested. The shoot height and root length were recorded after 30, 45 and 60 days after sowing. The highest shoot height was recorded in [T.sub.3] treatment after 60DAS. In case of root length in comparison to all the treatments mycorrhizal treatment [T.sub.3] (10 ppm arsenic solution + mycorrhiza) gave the highest result and those were 22.87cm and 28.07cm at 45DAS and 60DAS respectively and the lowest root length of eggplant was recorded in case of treatment [T.sub.4] (100 ppm arsenic solution) and those were 20.27cm and 21.37cm at 45DAS and 60DAS respectively. In all the three recorded periods it was observed that the shoot height and root length of eggplant decreased with the increase of arsenic concentration. Among the treatments, [T.sub.6] gave the lowest result so it was clearly exposed that with the increase of arsenic concentration the root length of eggplant decreased.
The influence of AMF inoculation on fresh weight of shoot and fresh weight of root of eggplant at different growth periods in soil amended with different concentrations of arsenic solution is presented in Table 3. The highest fresh weight of shoot was recorded in treatment [T.sub.3] followed by treatment [T.sub.2] [T.sub.5] and the lowest fresh weight of shoot was recorded in treatment [T.sub.7] at 30 DAS. Similar results were also obtained at 45 DAS and 60 DAS. On the other hand, treatment [T.sub.3] (10 ppm arsenic solution + mycorrhiza) gave the highest results in case of fresh weight of root and those were 8.97g, 8.99g and 10.93g at 30 DAS, 45 DAS and 60 DAS respectively which was significantly better in comparison to each of the other treatments. Incase of treatment [T.sub.2] and [T.sub.4] it was clearly showed that with the increase of arsenic concentration the fresh weight of shoot and fresh weight of root of brinjal decreased. Incase of only arsenic treatment [T.sub.2] (10 ppm arsenic solution) the fresh weight of shoot of eggplant at 60DAS was13.75 g but it increased up to 19.18 g when mycorrhiza were inoculated with that 10 ppm arsenic solution. Moreover, the fresh weight of root of eggplant at 60 DAS was 9.45 g but it increased up to 10.93 g when mycorrhiza was inoculated with that 10 ppm arsenic solution.
The influence of AMF inoculation on dry weight of shoot and dry weight of root of eggplant in soil, amended with different concentrations of arsenic solution is presented in Table 4. There was a remarkable variation of dry weight of shoot among the 7 different treatments. The variation of dry weight of shoot of eggplant was recorded due to the effect of mycorrhiza inoculation against arsenic solution. Result revealed that treatment [T.sub.3] (10 ppm arsenic solution + mycorrhiza ) gave the highest 1.67 g, 1.93 g and 1.99 g dry weight of shoot at 30 DAS, 45 DAS and 60 DAS respectively and on the other hand treatment [T.sub.3] (10 ppm arsenic solution + mycorrhiza ) also gave the highest dry weight of root and those were 0.53 g 1.16 g and 1.74 g at 30 DAS, 45 DAS and 60 DAS respectively which is significantly different and better in comparison to each of the other treatments. The dry weight of shoot and the dry weight of root of eggplant decreased when the rate of arsenic concentration increased. But AMF inoculation significantly increased dry weight in arsenic amended soil in compare to the arsenic treatment alone without AMF inoculation.
The inoculation of arbuscular mycorrhizal fungi in response to nutrient uptake (N, P, K and S), arsenic uptake and chlorophyll content by eggplant shoots at 60 DAS is represented in Table 5. It is revealed from the study that mycorrhizal fungi have a positive role in response to nutrient uptake and mycorrhizal fungi inoculated treatments significantly enhanced nutrient uptake by eggplant shoot in comparison to other treatment. The highest nutrient uptake was recorded in case of treatment [T.sub.3] (10 ppm arsenic solution + mycorrhiza) and those were 2.7 % total N, 0.77 % P, 4.56 % K and 0.77 % S and the lowest result was found in case of treatment [T.sub.6] (500 ppm arsenic solution) and those were 1.53 % total N, 0.30 % P, 1.41 % K and 0.27 % S.
Due to inoculation of AMF, lower amount of arsenic was found in AMF inoculated plants than noninoculated ones. The amount of arsenic increased with the increase rate of arsenic concentrations but in all the cases inoculation of AMF reduced arsenic uptake. The lowest amount of arsenic was found in treatment [T.sub.3] (10 ppm arsenic solution + mycorrhiza) and that was 59 ppm on the other hand the highest amount was found in treatment [T.sub.6] (500 ppm arsenic solution) and that was 159 ppm. Between the treatment [T.sub.2] and [T.sub.3] the amount of arsenic was higher in treatment [T.sub.2] and that was 129.3 ppm but inoculation of mycorrhiza significantly decreased As to 59.0 ppm.
In case of chlorophyll content by shoots the lowest amount of chlorophyll was found in treatment [T.sub.7] (500 ppm arsenic solution + mycorrhiza) and that was 0.1177 ppm. On the other hand the highest amount was found in treatment [T.sub.3] (10 ppm arsenic solution + mycorrhiza) and that was 0.2243 ppm. Among the treatment [T.sub.2], [T.sub.4] and [T.sub.6], the amount of chlorophyll was higher in treatment [T.sub.2] and that was 0.1437 ppm and lower in treatment [T.sub.6].
Arsenic solution reduced seedling emergence at 10 and 15 DAS in all the concentration tested. But the seedling emergence is increased when mycorrhiza was inoculated in the arsenic amended soil. Regarding this parameter in response to arsenic amended soil not enough work had been done so far. Saha (2008) reported that AMF inoculation significantly increased seedling emergence of tomato, radish and grown in arsenic contaminated soil. The findings of the present study is also suppoted by Akhter (2008).
The results of this experiment indicated that, shoot height and root length of eggplant were higher in all the mycorrhiza inoculated treatments than non-inoculated treatments. Shoot height and root length differs significantly due to the relevance of different concentrations of arsenic solution and inoculation of mycorrhiza. Among the 7 treatments, treatment [T.sub.3] (10 ppm arsenic + mycorrhiza) gave the best result whereas, treatment [T.sub.6] (500 ppm arsenic solution) gave the lowest result of plant growth and biomass in all the three recorded periods. Mycorrhizal inoculation significantly enhanced shoot height and root length in comparison to noninoculated. This was probably due to uptake of more nutrients, which increased vegetative growth. Present findings are in agreement with Vishwakarma and Singh, 1996 and Matsubara et al. (1994) who investigated the effects of inoculation with Vesicular-arbuscular mycorrhizal fungi (Glomus etunicatum or Glomus intraradices) on seedling growth of 17 vegetable crop species and reported that the growth was noticeably enhanced by VAMF inoculation to Spinach, Water Spinach, Indian Spinach, White Gourd and Cucumber.Shoot height and root length of brinjal was decreased with the increase of arsenic concentrations. Ultra et al. (2007) reported the AM inoculation as well as P application reduced As toxicity symptoms in the +AM-P treatment. They also reported that Plant growth was highest in the +AM + P treatment. The findings of Xia et al., 2007 is similar with the findings of present study. They conducted an experiment under glasshouse condition in an As-contaminated soil and they reported arbuscular mycorrhizal (AM) fungus (Glomus mosseae) increased both root length markedly under the zero-P treatments. Ahmed et al. (2006) reported that plant height, plant biomass and shoot and root P concentration increased significantly due to mycorrhizal infection and the parameters decreased significantly with increasing As concentration.
A significant reduction of fresh and dry weight of shoot and root of eggplant was recorded due to arsenic treatment in soil. The fresh and dry weight of shoot and root of brinjal were recorded after 30, 45 and 60 days of sowing. In comparison to all the treatments better result was obtained where mycorrhiza was inoculated than non-inoculated. The results indicated a positive effect of mycorrhizal inoculation on fresh and dry weight of shoot and root when soil amended with different concentrations of arsenic solution. This was probably due to the uptake of nutrient, which increased vegetative growth and hence greater translocation of photosynthetic product from leaf to shoot and thereby enhanced shoot growth and weight. Tarafdar and Parveen, (1996) reported that shoot biomass was significantly improved in mycorrhiza inoculated plants. The results of the present study corroborates with the findings of Carling and Brown, 1980 who reported that root colonization by most of the Glomus isolates significantly increased plant shoot dry weight in low fertility soil. Fresh weights of root and shoot increased when the plants were inoculated with AMF (Matsubara et al., 1994). Root and shoot dry weights were higher in mycorrhizal than non-mycorrhizal plants is reported by Giri et al., 2005. The findings of the present study is in accordance with the findings of Xia et al. (2007) who reported that both of dry weight and root biomass of maize plants increased markedly when inoculated with arbuscular mycorrhizal (AM) fungus (Glomus mosseae) under glasshouse condition in an arsenic amended soil. The present findings are also in accordance with the findings of Ahmed et al., 2006, where they reported that plant height, leaf/ pod number, plant biomass, root length and mycorrhizal infection decreased significantly with increasing As concentration. Agely et al. (2005) found that the AM fungi not only tolerate As amendment, but their presence increased dry mass at the highest As application rate.
It is revealed from the study that the arbuscular mycorrhizal fungi have a positive role in response to nutrient uptake (N, P, K and S). Mycorrhiza inoculated treatments significantly enhanced nutrient uptake by crops shoots in comparison to other treatments. Results of this experiment showed that with the increase of arsenic concentration the percentage of nutrient uptake decreased. Arbuscular mycorrhizal (AM) fungus had their most significant effect on P uptake. Dong et al. (2007) investigated the influence of AM inoculation on plant growth, phosphorus (P) nutrition, and plant competitions and they reported that mycorrhizal inoculation substantially improved plant P nutrition and in contrast markedly decreased root to shoot As translocation and shoot As concentrations. Khan et al. (1995) identified that nitrogen fixation as well as N and P contents in groundnut increased only by dual inoculation with AM fungi and Bradyrhizobium. Nutrient uptake was enhanced significantly in soybean shoot by inoculation of AM fungi. The VAM fungi promote phosphorus uptake in low phosphate soil during the early stages of plant growth (Sasai, 1991). Shnyreva and Kulaev (1994) identified the effect of VAM mycorrhization on maize plants by Glomus spp., phosphorus content in the VA-mycorrhizal root tissues increased by 35 % for the species G. mosseae and by 98 % for G. fasciculatum. Phosphorus uptake was influenced significantly by the inoculation of AM fungi over control by many selected crops. Nutrient uptake was enhanced significantly in Pigeon pea shoot by inoculation of AM fungi.
Bangladesh is one of the most densely populated countries and crop production need to be increased through a low imputes method. Mycorrhizal technology would be least expensive, simple and nature farming technology. Increased crop production and decreased arsenic toxicity of eggplant has particularly importance for human health and suggests that mycorrhizal inoculation may contribute to minimize As intake through consumption of crops grown in arsenic contaminated areas of Bangladesh.
Agely, A.A., D.M. Sylvia, and L.Q. Ma, 2005. Mycorrhizae increase arsenic uptake by the hyperaccumulator Chinese brake fern (Pteris vittata L.). J. Environ. Qual., 34(6): 2181-2186.
Akther, B., 2008. Mycorrhizal status of crops grown in arsenic affected areas of Sonargaon and influence of mycorrhizae on growth of selected crops in arsenic amended soil. M.S. Thesis. Department of Plant Pathology, Sher-e-Bangla Agricultural University, Dhaka.
Ahmed, F.R.S., K. Killham and I. Alexander, 2005. Influences of arbuscular mycorrhizal fungus Glomus mosseae on growth and nutrition of lentil irrigated with arsenic contaminated water. Plant Soil., 283(1-2): 33-41.
Alam, M.G., G. Allinson., F. Stagnitti., A. Tanaka and M. Westbrooke, 2002. Arsenic contamination in Bangladesh groundwater: a major environmental and social disaster. Int. J. Environ. Health Res., 12: 235253.
Barea, J.M., 1991.Vesicular-arbuscular mycorrhizae as modifiers of soil fertility. In: Stewart, B. A. (ed.), Advan. Soil Science. Springer-verlag, New York, Inc. pp: 1-40.
BBS (Bangladesh Bureau of Statistics). 2007. Monthly Statistical Bulletin, June. Ministry of Planning, Government of the People's Republic of Bangladesh, Dhaka, pp: 66-67.
Bonifacio, E., G. Nicolotti, E. Zanini and G. P. Cellerino, 1999. Heavy metal uptake by Mycorrhizae of beech in contaminated and uncontaminated soils. Fresenius Environ. Bull., 7: 408-413.
Bradley, R., A.J. Burt and D.J. Read, 1981. Mycorrhizal infection and resistance to heavy metal toxicity in Calluna vulgaris. Nature, 292: 335-337.
Bradley, R., A.J. Burt, and D.J. Read, 1982. The biology of mycorrhiza in the Ericaceae.VIII. The role of mycorrhizal infection in heavy metal resistance. New Phytol., 91: 197-209.
Brown, M.T. and D.A. Wilkins, 1985. Zinc tolerance of mycorrhizal Betula. New Phytol., 99: 101-106.
Cao, X., L.Q. Ma and A. Shiralipour, 2003. Effects of compost and phosphate amendments on arsenic mobility in soils and arsenic mobility in soils and arsenic uptake by the hyper accumulator pteris vitata L. Environ pollut. 126: 157-167.
Carling, D.E. and M.F. Brown, 1980. Relative effect of vesicular mycorrhizal fungi on growth and yield of soyabeans. Soil Sci. Soi. America J., 44(3): 528-592.
Das, H.K., A.K. Mitra., A. Hossain., F. Isalm and G.H. Rabbani, 2004. Arsenic concentrations in rice, vegetables and fish in Bangladesh: a preliminary study. Environ. Int. 30: 383-387.
Dong, Y., Y.G. Zhu, F.A. Smith, Y. Wang and B. Chen, 2007. Arbuscular mycorrhiza enhanced arsenic resistance of both white clover (Trifolium repens Linn.) and ryegrass (Lolium perenne L.) plants in an arsenic-contaminated soil. Department of Soil Environmental Science, Research Center for EcoEnvironmental Sciences, the Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085, China.
Giri, B., R. Kapoor and K.G. Mukerji, 2005. Effect of the Arbuscular Mycorrhizae Glomus fasciculatum and G. macrocarpum on the growth and nutrient content of Cassia siamea in a semi-arid Indian wasteland soil. New Forests., 29(1): 63-73.
Gonzalez, C.C., P.J. Harris and J. Dodd, 2002. Arbuscular mycorrhizal fungi confer enhanced arsenate resistance on Holcus lanatus. New Phytol., 155: 163-171.
Harrison, M.J., G.R. Dewbre and J. Liu, 2002. A phosphate transporter from Medicago trunculata involved in the acquisition of phosphate released by arbuscular mycorrhizal fungi. Plant Cell., 14: 1-17.
Hayman, D.S., 1983. The physiology of vesicular-arbuscular endomycorrhizal symbiosis. Can. J. Bot., 61(3): p: 944-963.
Khan, M.K., K. Sakamoto and T. Yoshida, 1995. Dual inoculation of ground nut with Glomus sp. and Bradyrhizobium sp. enhanced the symbiotic nitrogen fixation assessed by 15 N-technique. Soil sci. Pl Nutri., 41(4): 769-779.
Koske, R.E. and J.N. Gemma, 1989. A modified procedure for staining roots to detect VA-mycorrhizas. Mycol. Res., 92: 486-488.
Leyval, C., K. Turnau, and K. Haselwandter, 1997. Effect of heavy metal pollution on mycorrhizal colonization and function: physiological, ecological and applied aspects. Mycorrhiza., 7: 139-153.
Marschner, H. and B. Dell, 1994. Nutrient uptake in mycorrhizal symbiosis. Plant soil., 159: 89-102.
Masri, B.M., 1997. Mycorrhizal inoculation for growth enhancement and improvement of the water relations in mungosteen (Garcinia mangostana L.) seedlings. Ph. D. Thesis. University putra Malaysia. Serdung. Malaysia.
Matsubara, V. I., T. Haraba and T. Yakuwa, 1994. Effect of vesicular-arbuscular mycorrhizal fungi inoculation on seedling growth in several species of vegetable crops. J. Jap. Soci. Hort. Sci., 63(3): 619-628.
Meharg, A.A. and J.W.G. Cairney, 1999. Co-evolution of mycorrhizal symbionts and their hosts to metal contaminated environments. Adv. Ecol. Res., 30: 70-112.
Meharg, A.A. and M.R. Macnair, 1992. Suppression of the high affinity phosphate uptake system: a mechanism of arsenic tolerance in Holcus lanatus L. J. Exp. Bot., 43: 519-524.
Melamed, R., J.J. Jurinak and L.M. Dudley, 1995. Effect of adsorbed phosphate on transport of arsenate through an oxisol. Soil Sci. Soc. Am. J. 59: 1289-1294.
Mosse, B., 1973. Advances in the study of vesicular-arbuscular mycorrhiza. Annu. Rev. Phytopathol., 11: 171-196.
Mridha, M.A.U., A. Sultana., N. Sultana., H.L. Xu and H. Umemura, 1999. Biodiversity of VA mycorrhizal fungi of some vegetable crops in Bangladesh. Proc. International Symposium on World Food Security and Crop Production Technologies for Tomorrow, October 8-9, 1998. Kyoto, Japan, pp: 330-331.
Peryea, F.J. and R. Kammereck, 1997. Phosphate-enhanced movement of arsenic out of lead arsenate contaminated topsoil and through uncontaminated subsoil. Water Air Soil Pollut., 93: 243-254.
Saha, N.K., 2008. Mycorrhizal status of crops grown in arsenic affected areas of Manikganj district and effect of mycorrhiza on growth of some crops in arsenic amended soil. M.S. Thesis. Dept. of Pl. path. Sher-e Bangla Agricultural University, Bangladesh.
Sasai, K., 1991. Effect of phosphate application on infection of vesicular arbuscular mycorrhizal fungi in some horticultural crops. Scientific Rep. Miyagi Agric. Coll., 39: 1-9.
Sharples, J.M., A.A. Meharg., S.M. Chambers and J.W.G. Cairney, 2000a. Mechanism of arsenate resistance in the Ericoid mycorrhizal fungus Hymenoscyphus ericae. Plant Physiol., 124: 1327-1334.
Sharples, J.M., A.A. Meharg, and S.M. Chambers, 2000b. Symbiotic solution to arsenic contamination. Nature, 404: 951-952.
Shnyreva, A.V. and I.S. Kulaev, 1994. Effect of vesicular arbuscular mycorrhiza on phosphorus metabolism in agricultural plants. Microb. Res., 149(2): 139-143.
Smith, E., R. Naidu and A.M. Alston, 1998. Arsenic in the soil environment: A review. Adv. Agron. 64: 149-195.
Smith, S.E. and D.J. Read, 1997. Mycorrhizal Symbiosis, 2nd edn. Academic Press, London, U.K.
Tarafdar, J.C. and K. Praveen, 1996. The role of Vesicular Arbuscular Mycorrhizal fungi on crop, tree and grasses grown in an arid environment. J. of Arid Envirt., 34: 197-203.
Ultra, V.U., S. Tanaka, K. Sakurai and K. Iwasaki, 2007. Effects of arbuscular mycorrhiza and phosphorus application on arsenic toxicity in sunflower (Helianthus annuus L.) and on the transformation of arsenic in the rhizosphere. Plant Soil., 290(1-2): 29-41.
Xia, Y.S., B.D. Chen, P. Christie, A. Smith, Y.S. Wang and X.L. Li, 2007. Arsenic uptake by arbuscular mycorrhizal maize (Zea mays L.) grown in an arsenic -contaminated soil with added phosphorus. J. Environ. Sci., 19(10): 1245-1251.
(1) F. E. Elahi, (2) M. A. U. Mridha and (3) F.M. Aminuzzaman
(1) Division of Plant Pathology, Regional Agricultural Research Station, Bangladesh Agricultural Research Institute, Jamalpur, Bangladesh,
(2) Department of Botany, University of Chittagong, Bangladesh and
(3) Department of Plant Pathology, Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh
Corresponding Author: F.M. Aminuzzaman, Division of Plant Pathology, Regional Agricultural Research Station, Bangladesh Agricultural Research Institute, Jamalpur, Bangladesh,
Table 1: Influence of AMF inoculation on seedling emergence of eggplant at different growth periods in arsenic amended soil Treatments Seedling emergence 7 DAS 10 DAS 15 DAS [T.sub.1] 12.60ab 15.00 a 15.20 ab [T.sub.2] 14.60ab 14.60 a 15.00 ab [T.sub.3] 14.80ab 15.20 a 18.00 a [T.sub.4] 11.20 b 12.00 a 12.20 ab [T.sub.5] 13.80ab 14.40 a 14.60 ab [T.sub.6] 13.20ab 14.80 a 15.40 ab [T.sub.7] 11.80ab 12.40 a 13.20 b LSD 3.164 3.596 2.993 CV (%) 8.44 9.60 5.18 DAS= Days after sowing [T.sub.1] = Control, [T.sub.2] =10 ppm arsenic solution, [T.sub.3]=10 ppm arsenic solution + mycorrhiza, [T.sub.5] = 100 ppm arsenic solution, [T.sub.1] =100 ppm arsenic solution+ mycorrhiza, T6 =500 ppm arsenic solution, T7 =500 ppm arsenic solution+ mycorrhiza Table 2: Influence of AMF inoculation on shoot height and root length of eggplant at different growth periods in arsenic amended soil Treatments Shoot length (cm) 30 DAS 45DAS 60DAS [T.sub.1] 18.69abc 18.97bc 20.73ab [T.sub.2] 17.97bc 17.37c 18.03bc 16.50bcd 20.70a 21.80c [T.sub.3] 20.10ab 21.43a 22.20a [T.sub.4] 18.13bc 19.03c 19.80ab [T.sub.5] 21.67a 20.77a 19.60bc [T.sub.6] 17.67bc 18.73c 17.83c [T.sub.7] 16.90c 18.03c 18.57bc LSD 2.762 1.827 2.325 CV (%) 9.43 5.01 9.32 Treatments Root length (cm) 30 DAS 45 DAS 60 DAS [T.sub.1] 15.67cd 20.77a 21.63c [T.sub.2] [T.sub.3] 17.40abc 22.87a 28.07a [T.sub.4] 18.47a 20.27a 21.37c [T.sub.5] 19.17a 22.37a 22.03c [T.sub.6] 14.53d 20.53a 21.03c [T.sub.7] 19.37a 21.73a 23.67b LSD 2.446 3.188 1.832 CV (%) 6.24 4.45 8.89 DAS = Days after sowing [T.sub.1] = Control, [T.sub.2] =10 ppm arsenic solution, [T.sub.3]=10 ppm arsenic solution + mycorrhiza, [T.sub.4] = 100 ppm arsenic solution, [T.sub.5] =100 ppm arsenic solution+ mycorrhiza, T6 =500 Table 3: Influence of AMF inoculation on fresh weight of shoot and root of eggplant at different growth periods in arsenic amended soil Treatments Fresh weight of shoot (g) 30 DAS 45 DAS 60 DAS [T.sub.1] 8.77b 9.57abc 11.47bc [T.sub.2] 10.77a 10.53ab 13.75b [T.sub.3] 8.43bc 11.24a 19.18a [T.sub.4] 6.93d 7.58bc 12.99b [T.sub.5] 6.88d 10.10ab 13.41b [T.sub.6] 7.91c 8.63abc 10.55b [T.sub.7] 6.71d 7.03c 8.90c LSD 0.733 2.792 3.443 CV (%) 5.07 5.68 4.36 Treatments Fresh weight of root (g) 30 DAS 45 DAS 60 DAS [T.sub.1] 8.79a 8.57a 8.73b [T.sub.2] 8.46a 8.57ab 9.45b [T.sub.3] 8.97a 8.99ab 10.93a [T.sub.4] 5.67b 5.89b 6.75c [T.sub.5] 6.21b 7.31ab 7.21c [T.sub.6] 6.75b 7.63ab 7.55c [T.sub.7] 6.31b 6.73ab 6.91c LSD 1.533 2.042 9.190 CV (%) 6.08 6.87 9.98 DAS = Days after sowing [T.sub.1] = Control, [T.sub.2] =10 ppm arsenic solution, [T.sub.3]=10 ppm arsenic solution + mycorrhiza, [T.sub.4] = 100 ppm arsenic solution, [T.sub.5] =100 ppm arsenic solution + mycorrhiza, [T.sub.6] =500 ppm arsenic solution, [T.sub.7] = 500 ppm arsenic solution+ mycorrhiza Table 4: Influence of AMF inoculation on dry weight of shoot and root of eggplant at different growth periods in arsenic amended soil Treatments Dry weight of shoot (g) 30 DAS 45DAS 60DAS [T.sub.1] 1.58 1.42 1.69 [T.sub.2] 1.4 1.40 1.45 [T.sub.3] 1.67 1.93 1.99 [T.sub.4] 1.57 1.39 1.58 [T.sub.5] 1.36 1.27 1.58 [T.sub.6] 1.06 1.21 1.40 [T.sub.7] 1.40 1.03 1.54 LSD NS NS NS CV (%) 5.5 6.90 7.77 Treatments Dry weight of root (g) 30 30 DAS 45 DAS 60 DAS [T.sub.1] 0.50a 0.98 1.61c [T.sub.2] 0.26ab 0.73 1.40abc [T.sub.3] 0.53a 1.16 1.74a [T.sub.4] 0.14b 0.82 1.08ab [T.sub.5] 0.29ab 0.85 1.25bc [T.sub.6] 0.26ab 0.63 0.49d [T.sub.7] 0.39ab 0.52 0.62d LSD 0.3132 NS 0.3898 CV (%) 8.81 7.89 5.78 DAS = Days after sowing [T.sub.1] = Control, [T.sub.2] = 10 ppm arsenic solution, [T.sub.3] = 10 ppm arsenic solution + mycorrhiza, [T.sub.4] = 100 ppm arsenic solution, [T.sub.5] = 100 ppm arsenic solution + mycorrhiza, [T.sub.6] = 500 ppm arsenic solution, [T.sub.7] = 500 ppm arsenic solution+ mycorrhiza Table 5: Influence of AMF inoculation on nutrient uptake, arsenic uptake and chlorophyll content of eggplant grown in arsenic amended soil Treatments Nutrient uptake Total N % P % K % S % [T.sub.1] 2.10 c 0.63ab 2.40bc 0.40bc [T.sub.2] 1.56 d 0.48ab 2.64bc 0.76a [T.sub.3] 2.70 a 0.76ab 4.56a 0.77a [T.sub.4] 2.56 a 0.43ab 4.13a 0.46b [T.sub.5] 2.33 b 0.56ab 3.40ab 0.40b [T.sub.6] 1.53 d 0.30 b 1.41cd 0.27c [T.sub.7] 2.13 c 0.45a 1.41cd 0.64a LSD 0.1949 0.3375 1.226 0.1378 CV (%) 5.18 4.78 6.46 4.64 Treatments Arsenic Chlorophyll (As) content (ppm) (mg/g) [T.sub.1] 0.00 d 0.1260 b [T.sub.2] 129.3 a 0.1437 b [T.sub.3] 59.00 b 0.2243 a [T.sub.4] 51.00 c 0.1340 b [T.sub.5] 86.00 b 0.1617 b [T.sub.6] 159.00a 0.1320 b [T.sub.7] 80.33 a 0.1173 b LSD 32.18 2.18 CV (%) 8.79 9.98 [T.sub.1] = Control, [T.sub.2] = 10 ppm arsenic solution, [T.sub.3] = 10 ppm arsenic solution + mycorrhiza, [T.sub.4] = 100 ppm arsenic solution, [T.sub.5] = 100 ppm arsenic solution + mycorrhiza, [T.sub.6] = 500 ppm arsenic solution, [T.sub.7] = 500 ppm arsenic solution+ mycorrhiza