Effect of different arsenic-treatments on the dry weight of vegetative plant parts of green pea in the different phenophase of the plant development

Annals of the Academy of Romanian Scientists Series on Science and Technology of Information ISSN 1234-567X Volume x, Number x/20xx 1 EFFECT OF DIFFERENT ARSENIC-TREATMENTS ON THE DRY WEIGHT OF VEGETATIVE PLANT PARTS OF GREEN PEA IN THE DIFFERENT PHENOPHASE OF THE PLANT DEVELOPMENT Szilvia VÁRALLYAY 1 Andrea BALLÁNÉ KOVÁCS 2 , Áron SOÓS 3 , Béla KOVÁCS 4 , Abstract. The objective of our study was to investigate the effect of arsenate and arsenite on dry weight of root, stem and leaves of green pea in the four different growth phases (four-node condition, the beginning of flowering, green ripening, and complete maturity) of the plant developement. As a results of our experiment shows, in some cases there were significant differences beetwen the effect of As(III)- and As(V)-treatmnets. Based on the data, in the case of the all phenophase, As(III)-treatments has a negatvive effect on the dry mass of vegetative plant parts. According to the results, in the case of the first phenopase the 3 mg kg-1 As(V)-treatments, in the case of the further phenophase the 3 and 10 mg kg-1 As(V)-treatment increased, but the higher concentration of As(V) decreased the dry mass of leaves and stem. Hovewer, the dry weigth of root was sightly increased in the first and second phenophase of the plant develompent as a result of the 3 mg kg-1 As(V)-treatmnet, the dry mass of root was negatively effected by the As(V)-treatments. Keywords: arsenite, arsenate, green pea, dry weight, pot experiment 1. Introduction Arsenic (As) is a toxic element that is found naturally in soils all over the world [1]. Most environmental arsenic problems are the result in mining activities, use of arsenical herbicides and insecticides, irrigation with arsenic contaminated groundwater and some other agricultural and anthropogenic factors [2, 3, 4, 5]. The pollution of soil and groundwater with arsenic is a serious environmental 1 Junior Researcher, Institute of Food Science, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Debrecen, Hungary ([email protected]). 2 Associate professor, PhD, Department of Agricultural Chemistry and Soil Sciences, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Debrecen, Hungary ([email protected]). 3 Junior Researcher, Institute of Food Science, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Debrecen, Hungary ([email protected]). 4 Prof. PhD, Institute of Food Science, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Debrecen, Hungary ([email protected]). 2 Szilvia Várallyay, Andrea Balláné Kovács, Áron Soós, Béla Kovács problem all over the world [4, 6]. Arsenic is non-essential moreover toxic to plants [5, 7]. The phytotoxicity of arsenic depends on the form of the arsenic speciation and just only secondarily depends on the total concentration [8]. Inorganic arsenic forms are usually more toxic to plants, than organic compounds [9]. Arsenic in soil mostly found as inorganic form, namely arsenate [As(V)] and arsenite [As(III)]. Both are easily taken up by the cells of the plant root [10, 11]. Excessive uptake of arsenic by plants have led to physiological changes [12, 13]. Arsenic could inhibit the normal growth of the plants with toxicity symptoms such as morphological changes [14, 15] reduction of the plants productivity [16, 17] and loss of biomass [18]. The objective of this study was to investigate the physiological response of green peas to different As-treatments, evaluated by the parameters of dry mass of shoot, root, leaves, peas and pods in the four different phase of plant development. 2. Materials and methods The pot experiment was carried out in calcareous chernozem soil was collected from the Látókép Experimental Station of the University of Debrecen. The parameters of the experimental soil were published previously by Kovács et al. (2015) [19]. 11 kg soil was weighed into each pot. The soil was air dried, sieved and additional NPK fertilization was applied (Table 1). Table 1) Doses of NPK-fertilizer was applied in the greenhouse experiment Doses of NPK-fertilizer N P K NH4NO3 (g pot-1) KH2PO4 (g pot-1) KH2PO4 (g pot-1) K2SO4 (g pot-1) 0.568 0.229 0.079 0.148 Arsenic was applied in the form of arsenite (NaAsO2) and arsenate (KH2AsO4), separately in seven different levels respectively as follows: 0 (control), 1, 3, 10, 30, 90 and 270 mg kg-1. The NPK fertilizer and the arsenate as well as arsenite was supplemented to the soil as an aqueous solution. Green pea (Pisum sativum L.) was chosen for our research to study the effect of different arsenic treatments on the dry weight of plant since it is one of the vegetables grown in the largest area in Hungary. Twenty-five seeds were planted in each pots and after the germination the number of the plants was slowed to sixteen. The study was conducted in randomized complete block design with three replications. Pots were weighed daily and the water losses were refilled by applications of de-ionized water. Plants samples (four plant in each phenophase) were collected in the four different phase of the plant development (four-node condition, the beginning of flowering, green ripening, and complete maturity). Effect of different arsenic-treatments on the dry weight of vegetative plant part’s of green pea in the different phenophase of the plant development 3 The roots of the plants were washed to eliminate the soil by distilled water. The dry weights were recorded after drying the root, stem, leaves, peas and pods at 65°C until a constant weight was achieved. All data obtained from experiment were subjected to one-way analysis of variance (ANOVA) and Duncan's test at 0.05 significance level to compare populations and arsenic treatments, used by SPSS statistics software version 22.0. Independent Sample T-test was used to determine the statistically significant differences at 0.05, 0.01 and 0.001 significance levels between the effect of arsenate and arsenite at the same level. 3. Results 3.1. Effect of As(III)- and As(V)-treatments on the dry weight of green pea in the first phenophase of the plant development The effect of As(III)- and As(V)-treatments on the dry weight of individual 0plant’s part of green pea plants which were in four-node condition is demonstrate in the Table 3. Table 2) Dry weight (g plant-1) of individual plant’s part of green pea plants which were in four-node condition grown in the calcareous chernozem soil of Látókép depending on arsenic-treatments (0, 3, 10, 30, 90, 270 mg kg-1) Astreatments (mg kg-1) Dry weight (g plant-1) Leaves Stem Root As(III) 0 0.162±0.042a 0.123±0.039a 0.0223±0.0055a 3 0.135±0.01b 0.0817±0.0087b 0.0210±0.0046a 10 0.123±0.01b 0.0813±0.0069b 0.0178±0.0058a 30 0.117±0.007b 0.0785±0.0053b 0.0176±0.0059a 90 0.114±0.013b 0.0711±0.0083b 0.0107±0.0007b 270 0.0198±0.0056c 0.0207±0.0058c 0.0101±0.0034b As(V) 0 0.162±0.042a 0.123±0.039ab 0.0223±0.0055a 3 0.175±0.026a* 0.151±0.051b* 0.0312±0.0069b* 10 0.160±0.038a* 0.111±0.014ab 0.0215±0.0048a 30 0.121±0.028b 0.0837±0.0154a 0.0181±0.0051a 90 0.109±0.024b 0.0740±0.0119ac 0.0164±0.0016a* 270 0.0215±0.0052c 0.0287±0.0071c 0.0157±0.0053a Means followed by the same letter within columns, separately in the case of As(III) and As(V), were not significantly different according to Ducan’s multiple range test (P≤ 0.05). Means followed by *(p<0.05), **(p<0.01), ***(p<0.001) within columns were significantly different between the effect of As(III) and As(V) at the same level according to independent sample T-test. This values show that increasing amount of As(III)-treatment resulted statistically lower dry weight of the leaves and stem of experimental plants. Based on the data, 4 Szilvia Várallyay, Andrea Balláné Kovács, Áron Soós, Béla Kovács in the case of the root the 90 and 270 mg kg-1 As(III)-treatments also significantly reduced the dry weight. According to the data the 3 mg kg-1 As(V)-treatment statistically increased the dry weight of root. When the plants were treated with more than 10 mg kg-1 As(V), the dry weight of leaves were reduced, moreover the dry biomass of stem was also reduced when the plats were treated with 270 mg kg-1 As(V). Nevertheless, the 3 mg kg-1 As(V)-treatment significantly increased the dry mass of stem and root. 3.2. Effect of As(III)- and As(V)-treatments on the dry weight of green pea in the second phenophase of the plant development As a result of our experiments shows, the treatments of green pea with As(III) had a negative effect on the dry mass of stem. The dry weight of root and leaves were also reduced when the plants were treated with at least 30 mg kg-1 As(III). In addition it was observed that the dry mass of root, stem and leaves were decreased when the plants were treated with 90 and 270 mg kg-1 As(V). Nevertheless, the 10 mg kg-1 As(V)-treatment increased the dry mass of leaves (Table 3). Table 3) Dry weight (g plant-1) of individual plant’s part of green pea plants which were in the beginning of flowering grown in the calcareous chernozem soil of Látókép depending on arsenic-treatments (0, 3, 10, 30, 90, 270 mg kg-1) Astreatments (mg kg-1) Dry weight (g plant-1) Leaves Stem Root As(III) 0 0.192±0.048a 0.255±0.085a 0.0304±0.0077a 3 0.165±0.014ab 0.170±0.027b 0.0287±0.0095a 10 0.145±0.046ab 0.156±0.037b 0.0255±0.0053ab 30 0.133±0.041b 0.141±0.036b 0.0200±0.0059bc 90 0.128±0.030b 0.126±0.037b 0.0159±0.0051c 270 0.0298±0.0106c 0.0238±0.0046c 0.0130±0.0044c As(V) 0 0.192±0.048a 0.255±0.085a 0.0304±0.0077a 3 0.218±0.06a 0.266±0.07a 0.0335±0.0068a 10 0.311±0.078b** 0.345±0.081a** 0.0299±0.0079ab 30 0.208±0.056a* 0.276±0.07a 0.0267±0.0077abc 90 0.112±0.039c 0.122±0.025b 0.0202±0.0069bc 270 0.0294±0.0098d 0.0323±0.0079c 0.0189±0.0057c Means followed by the same letter within columns, separately in the case of As(III) and As(V), were not significantly different according to Ducan’s multiple range test (P≤ 0.05). Means followed by *(p<0.05), **(p<0.01), ***(p<0.001) within columns were significantly different between the effect of As(III) and As(V) at the same level according to independent sample T-test. Effect of different arsenic-treatments on the dry weight of vegetative plant part’s of green pea in the different phenophase of the plant development 5 3.3. Effect of As(III)- and As(V)-treatments on the dry weight of green pea in the third phenophase of the plant development In the case of the third phase of the plant development, dry weight of each plant part were decreased when the plant were exposed to 90 and 270 mg kg-1 As(V)- treatments. Nevertheless, the 30 mg kg-1 As(V)-treatments significantly increased the dry weight of leaves and stem. In the case if the leaves similar tendency was observed when the plants were treated with As(III). The 90 and 270 mg kg-1 As(III)-treatment significantly decreased the dry weight of leaves. The dry mass of root was not vary significantly under the As(III)-stress, however the biomass of stem was negatively affected by all As(III)-treatments (Table 4.). Table 4) Dry weight (g plant-1) of individual plant’s part of green pea plants which were in green ripening grown in the calcareous chernozem soil of Látókép depending on arsenic-treatments (0, 3, 10, 30, 90, 270 mg kg-1) As-treatments (mg kg-1) Dry weight (g plant-1) Leaves Stem Root As(III) 0 0.226±0.072a 0.299±0.087a 0.0463±0.0127ab 3 0.176±0.038ab 0.194±0.066b 0.0460±0.0149b 10 0.174±0.049ab 0.192±0.061b 0.0394±0.0087ab 30 0.173±0.059ab 0.185±0.041b 0.0341±0.0033ab 90 0.159±0.046b 0.176±0.057b 0.0323±0.0104ab 270 0.0379±0.0126c 0.0270±0.0074c 0.0293±0.0061b As(V) 0 0.226±0.072a 0.299±0.087a 0.0463±0.0127a 3 0.240±0.078a 0.306±0.068a* 0.0455±0.0035a 10 0.356±0.049b** 0.391±0.113b** 0.0452±0.0067a 30 0.248±0.055a* 0.299±0.046a*** 0.0415±0.0105ab 90 0.116±0.028c 0.133±0.028c 0.0300±0.0071bc 270 0.0340±0.0106c 0.0399±0.0124d* 0.0238±0.0072c Means followed by the same letter within columns, separately in the case of As(III) and As(V), were not significantly different according to Ducan’s multiple range test (P≤ 0.05). Means followed by *(p<0.05), **(p<0.01), ***(p<0.001) within columns were significantly different between the effect of As(III) and As(V) at the same level according to independent sample T-test. 3.4. Effect of As(III)- and As(V)-treatments on the dry weight of green pea in the fourth phenophase of the plant development The effect of As(III)- and As(V)-treatments was also evident on the vegetative plant’s part of green pea. The As(V)-treatments caused a similar tendency in the dry weight of leaves, stem and root as previously mentioned in the case of the third phenophase of the plant development. The 90 and 270 mg kg-1 As(V)- 6 Szilvia Várallyay, Andrea Balláné Kovács, Áron Soós, Béla Kovács treatments decreased the dry mass of the vegetative plant parts, however the 10 mg kg-1 As(V)-treatment increased the dry weight of leaves and stem. In the case of the leaves the dry mass was also positively affected by the 3 mg kg-1 As(III)- treatment. As in the case of the third phenophase of the plant development, the highest As(III)-treatment (270 mg kg-1) also significantly decreased the dry weight of the vegetative parts of the green pea, moreover the 90 mg kg-1 As(III)- treatment also decreased the dry mass of the root compared to the control as demonstrated in the Table 5. Table 5) Dry weight (g plant-1) of vegetative plant’s part of green pea plants which were in complete maturity grown in the calcareous chernozem soil of Látókép depending on arsenic-treatments (0, 3, 10, 30, 90, 270 mg kg-1) Astreatments (mg kg-1) Dry weight (g plant-1) Leaves Stem Root As(III) 0 0.24±0.061ab 0.305±0.064ab 0.0607±0.0119a 3 0.368±0.072c 0.374±0.129b 0.0565±0.0194ab 10 0.301±0.039bc 0.322±0.036ab 0.0527±0.0110ab 30 0.238±0.074ab 0.263±0.032ab 0.0450±0.0150ab 90 0.197±0.059a 0.209±0.028a 0.0430±0.0120b 270 0.0554±0.0182d 0.065±0.0107c 0.0249±0.0081c As(V) 0 0.24±0.061a 0.305±0.064a 0.0607±0.0119a 3 0.246±0.056a* 0.316±0.085a 0.0505±0.0097ab 10 0.379±0.052b* 0.465±0.108b* 0.0471±0.0092bc 30 0.262±0.037a 0.307±0.048a 0.0463±0.0119bc 90 0.127±0.036c 0.153±0.043c 0.0342±0.0074c 270 0.0435±0.0119d 0.0525±0.0154d 0.0341±0.0089c Means followed by the same letter within columns, separately in the case of As(III) and As(V), were not significantly different according to Ducan’s multiple range test (P≤ 0.05). Means followed by *(p<0.05), **(p<0.01), ***(p<0.001) within columns were significantly different between the effect of As(III) and As(V) at the same level according to independent sample T-test. Conclusion This study provides important information concerning the relationship between the levels of As in the soil and its impact on dry weight of the of individual plant’s part of green pea plants. According to the results, in the case of the all phenophase As(III)-treatments has a negative impact on the dry weight of the vegetative plant’s parts, however is statistically not supportable in all cases. Based on the data in the case of the first phenophase the lower concentration of As(V)-treatment (3 mg kg-1) increased, but the higher As(V)-treatments (10, 30, 90 and 270 mg kg-1) inhibited the dry mass accumulation, however is statistically also not supportable in all cases. In the case of the second, third and fourth phenophase of the plant development, increasing Effect of different arsenic-treatments on the dry weight of vegetative plant part’s of green pea in the different phenophase of the plant development 7 tendency was observed in the dry weight of leaves and stem until the 10 mg kg-1 As(V)-treatment, nevertheless decreasing tendency was observed in the case of the higher As(V)-treatments (30, 90 and 270 mg kg-1). However, in the case of the first phenophase as a result of the 3 mg kg-1 As(V)-treatment the dry weight of root was slightly increased and in the second phase also was slightly increased. Nevertheless, the dry mass of root was negatively affected by the As(V)- treatments in case of the other treatments and other phenophase of the green pea development. As a results of our experiment shows in some cases there were significant differences between the effect of As(III)- and As(V)-treatments. 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