Behavior of Tomato Plants as Affected by Spraying with Chitosan and Aminofort as Natural Stimulator Substances under Application of Soil Organic Amendments

This study was carried out during the summer seasons of 2007 and 2008 at the Experimental Farm of Environmental Agric. Sci. Fac., El-Arish, North Sinai, Egypt to study the effect of organic manures such as farmyard manure (FYM), and goat manure and spraying with some amendment substances; viz, chitosan and aminofort on growth, yield and some traits of fruit quality of tomato plants (pH and TSS%) under sandy soil conditions. The data revealed that tomato plants fertilized by goat manure and FYM, respectively as well as spraying of chitosan and aminofort significantly increased all vegetative parameters (plant height and number of both branches and leaves/plant), fresh and dry weight of different plant organs(roots, branches, leaves, and total of both fresh and dry weight of plant), photosynthetic pigments, yield /plant and marketable yield / feddan, but diseased yield (expressed in fruits infected by blossom end rot) was increased as a result of application of organic manures compared to control treatments. Meanwhile, application of chitosan decreased the diseased yield. On the other hand, pH and TSS (%) were not significantly affected.

INTRODUCTION

Tomato (Lycopersicum esculentum Mill.) is one of the major and important vegetable crop in Egypt which consumed in fresh or process forms. Tomato fruits contain some important nutritional compounds for human health such as vitamins and lycopen which helps counteract the harmful effects of radical effects which are thought to contribute to age-related process and a number of types of cancer (Khan et al., 2006). For increasing the productivity of tomato to meet the increment in human population, it could be achieved through increasing the cultivated area or improving the land productivity, especially in sandy soils.

Sandy soils had unfavorable physical, and biological properties. Addition of organic manures to sandy soil is very important to improve these unfavorable characters. It has a positive effect on soil acidity, soil exchange capacity and buffering the soil infiltration (Hsieh and Hsu, 1993). The foundation of organic manure application is enriching the microbial activity which increase the microbial activity, microbial-biomass, biomass C, N flush and consequently increasing the enzymes activities (Nur et al., 2006; Dinesh et al., 2000; Appireddy et al., 2008), increase the availability of macro and micronutrients in soils; viz., N, P, K, Ca , Mg, Fe, Zn, Mn, and Cu as a result of organic manure mineralization, reduction of fixation and complexing properties of these manures with macro and micronutrients (Rasoli and Forghani, 2006; Agbede et al., 2008). Organic manures increase the tolerance to insect disease, help control weeds, increase the health of plant and finally ensure produce quality (Ghorbani et al., 2008). Under organic farming, application of manure compounds for enhancing plant growth and increase the ability to disease and pests is necessary.

Among the promising approaches for inducing plant disease resistance and reducing damage from fungal pathogens and stimulate the immunity of plant is chitosan (Hadwiger et al., 2002). Chitosan is a natural polysaccharides, which consists of a copolymer of N-ace tyl-D-glucosamine and D-glucosamine residues, linked by β- 1,4 glycosidic bonds (Khin et al., 2006) . Chitosan is derived from chitin, a polysaccharide found in the exoskeleton of shellfish such as shrimp, lobster, and or crabs and cell walls of fungi (Wojdyla, 2001). Very few efforts were done to study the effect of chitosan on plant growth and its productivity which applied mainly as antimicrobial to protect plants from soil pathogenics or to increase the storability of fruits such as strawberry (Vargas et al., 2006). The results of application of chitosan revealed that chitosan can increase the immunity of plant (Patkowska et al., 2006), antimicrobial effect of chitosan on pathogenics and microparasitic fungi (Abou Sereih et al., 2007; Palma-Guerrero et al., 2008) which promotion of root system (Gornik et al., 2008), increase the plant health, the photosynthetic pigments and consequently the plant production (Chibu and Shibayama, 1999; Khan et al., 2002; Gornik et al., 2008).

Every plant like any organism needs certain compounds for growth over, the compounds of living cells as proteins, with building block material, and amino acids. Proteins are fundamental ingredients in the process of protein synthesis. Application of amino acids enhanced plant growth expressed in vegetative growth, fresh and dry weight of plant, helps to increase the chlorophyll concentration, achieved the set percentage and it required to increase the yield of tomato crop (Ting et al., 1998; Neeraja et al., 2005; Tantawy et al., 2009). Amino acids help to alleviate the negative effect of abnormal soil conditions such as salinity of water irrigation used (Abdel-Latif, 1995; Hafez, 2001).

So, that, the main objective of this study was to improve the sandy soil properties by using organic manures as soil amendments and application of some natural or biological stimulators as chitosan and amino acids to improve tomato plants growth and its productivity.

MATERIALS AND METHODS

A field experiment was carried out during the summer seasons of 2007 and 2008. The main object of this research was to study the effect of two of organic soil amendments; i.e., Farmyard manure, goat manure plus the check treatments (without manure) and spraying of tomato plants (cv. GS-12) with chitosan and amino acids.

Tomato plants were transplanted in a sandy soil (sand 95.70%, silt 2.46% and clay 1.33%; organic matter 0.05%; pH 7.93 and EC of 0.701 dS m^-1) recovered from 0-15 cm layer at The Experimental Farm of The Faculty of Environmental Agricultural Sciences, El-Arish, Suez Canal University, North Sinai Governorate, Egypt. EC and pH of irrigation water were7.72 dS m^-1 and 7.81, respectively. Total N, P and K were 2.01, 0.83, 1.21 and 0.49, 0.25, 0.52 for goat manure and FYM, respectively.

This experiment include nine treatments which are the combination between three sources of organic manures; viz., goat manure, farmyard manure and check treatment and spraying with two natural stimulator substances; viz., chitosan, aminofort and control treatment. Chitosan was applied as chito-care form. The chemical composition of chito-care and aminofort were shown in Table 1.

Organic manures were applied at a rate of 25 m³/fed. for goat manure and 40 m³ for FYM.

Treatments were randomly arranged in a split plot design with three replications. The organic manures were randomly arranged in the main plots, and spraying treatments (chitosan and aminofort) were randomly arranged in the sub plots.

Table 1:	The chemical composition of chito-care and aminofort

Plot area was 24 m² (24 m in length and 1m in width), and it was divided into 18 m² for yield and 6 m² for vegetative parameters. Plants were transplanted on May 5^th and 9^th in the 1^st and 2^nd seasons, respectively.

Organic manures were added in the mid of row, then covered and mixed with soil. Plants were sprayed four times at 10 days intervals beginning 20 days after transplanting. All plants received the recommended dose of NPK (124 kg N, 86 kg P₂O₅ and 144 kg k₂O/fed.). The other conventional practices were applied.

Data recorded
Vegetative growth: Samples of nine plants were randomly taken from each sub plot at 60 days from transplanting to estimate plant height, number of branches and leaves/ plant, fresh weight of roots, branches, leaves and total fresh weight. All plant parts were dried at 70°C till constant weight, and then dry weight of root, branches, leaves, and total dry weight of plant were calculated.

Photosynthetic pigments: Chlorophyll A, Chlorophyll B, total chlorophyll A+B, and carotenoids were recorded for the fourth leaf from the plant tip according to Wettstein (1957).

Yield and its components: Yield/plant, marketable yield/feddan, and disorder yield/feddan which estimated as the fruits that infected by blossom-end rot were measured.

Fruit quality: Random samples of six fruits were taken from each sub plot at the 2nd harvest, and pH and TSS% were estimated in the 2nd season only by pH meter and Carl Zeis refractometer, respectively.

Statistical analysis: Statistical analysis of the obtained data was carried out according to statistical analysis of variance according to Snedecor and Cochran (1980). Duncans multiple range tests was used for comparison among means (Duncan, 1958).

RESULTS

Vegetative growth
Effect of organic manures: Data in Table 2 shows that fertilization of tomato plants with goat manure increased plant height, number of branches/plant and number of leaves/plant in the first season as well as plant height in the second season without significant differences with application of FYM, while the control treatments recorded the lowest values of vegetative growth. The same data illustrate that there were no significant differences among the treatments on number of both branches and leaves/plant in the second season.

Effect of chitosan and aminofort: It is illustrate from the data shown in Table 2 that spaying tomato plants with chitosan increased all vegetative growth parameters expressed in plant height, number of branches, and number of leaves per plant in the first season and plant height in the second season without significant differences with spraying with Aminofort. Control treatment recorded the last rank belong to the previous parameters. The same data show that there were no significant differences among the treatments on number of both branches and leaves/plant in the second season.

Effect of interaction between organic manures and spraying with chitosan and aminofort: The increase in plant height was fluctuated between spraying tomato plants with aminofort with fertilization of FYM or spraying plants with chitosan with fertilization of goat manure in the first and second seasons, respectively (Table 3). Number of branches and leaves/plant significantly increased by fertilizing tomato plants with goat manure with spraying of chitosan.

Fresh and dry weight
Effect of organic manures: Data in Table 4 show that the fresh and dry weight of different plant organs; viz., roots, branches, leaves and both total fresh and dry weight of tomato plant were significantly affected by application of different organic manures. Goat manure treatment recorded the first rank which recorded the highest values of the abovementioned traits followed by application of FYM, while control treatment was the last.

Effect of spraying with chitosan and aminofort: It is clear from the data in Table 4 that spraying tomato plants with chitosan or aminofort increased the fresh and dry weight of roots, branches, leaves and both total fresh and dry weight of plant.

Table 2:	Effect of organic manures and spraying with chitosan and aminofort on vegetative growth of tomato plants
Values having the same letter(s) did not significantly differ at 0.05 level of significance, according to Duncan's multiple range test

Table 3:	Effect of interaction between organic manures and spraying with chitosan and aminofort on vegetative growth of tomato plants
Values having the same letter(s) did not significantly differ at 0.05 level of significance, according to Duncan's multiple range test

Table 4:	Effect of organic manures and spraying with chitosan and aminofort on fresh and dry weight of tomato plants
Values having the same alphabetical letter(s) did not significantly differ at 0.05 level of significance, according to Duncan's multiple range test

Table 5:	Effect of interaction between organic manures and spraying with chitosan and aminofort on fresh and dry weight of tomato plants
Values having the same alphabetical letter(s) did not significantly differ at 0.05 level of significance, according to Duncan's multiple range test

Effect of interaction between organic manures and spraying with chitosan and aminofort: All interaction treatments among application of goat manure or FYM with or without spraying with chitosan and aminofort increased the fresh weight of roots in the second season significantly. The same trend was found in the first season, except fertilization with FYM only (Table 5). It is also clear from the same data that the interaction between fertilization of goat manure with spraying with aminofort and chitosan, respectively were the superior treatments wherein increased fresh weight of branches, leaves, total fresh weight of plant, and the dry weight of the same parameters.

Photosynthetic pigments
Effect of organic manures: It is obvious from the data in Table 6 that fertilization of tomato plants with goat manure increased all the photosynthetic pigments; i.e., chlorophyll a, chlorophyll b, total chlorophyll (a + b) and carotenoids significantly. These results are true in both seasons.

Effect of spraying with chitosan and aminofort: Spraying tomato plants with chitosan or aminofort had a significant effect on components of photosynthetic pigments expressed in chlorophyll a, chlorophyll b, total chlorophyll (a + b) and carotenoids compared to control treatment (Table 6).

Effect of interaction between organic manures and spraying with chitosan and aminofort: Data in Table 7 show the effect of interaction between organic manures and spraying with chitosan and aminofort on photosynthetic pigments in tomato leaves. The data reveal that the highest concentration of photosynthetic pigments (chl.a, chl.b, and total chl.a+b as well as carotenoids) were achieved by the interaction between application of goat manure and spraying with chitosan followed by application of the same organic manure source and spraying with aminofort.

Table 6:	Effect of organic manures and spraying with chitosan and aminofort on photosynthetic pigments of tomato plants
Values having the same letter(s) did not significantly differ at 0.05 level of significance, according to Duncan's multiple range test

Table 7:	Effect of interaction between organic manures and spraying with chitosan and aminofort on photosynthetic pigments of tomato plants
Values having the same alphabetical letter(s) did not significantly differ at 0.05 level of significance, according to Duncan's multiple range test

Fig. 1:	Effect of organic manures on plant yield of tomato

Yield
Effect of organic manures: It is clear from Fig. 1 that application of goat manure was the best treatment for increasing yield/plant without significant difference with fertilization of FYM, while control treatment recorded the lowest value of yield/plant.

Fig. 2:	Effect of organic manures on marketable yield of tomato plants

Concerning the marketable yield/fed, Fig. 2 shows that fertilization with goat manure and FYM, respectively increased the marketable yield/fed by 40.39, 54.58 and 22.25, 44.03% over the control treatment in both seasons. On the other hand, the both sources of organic manures increased the disorded yield/fed. compared to the control treatment. This increment was high with application of goat manure (Fig. 3).

Effect of spraying with chitosan and aminofort: Figure 4 shows the effect of spraying tomato plants with chitosan and aminofort on yield/plant. It is clear that spaying with chitosan or aminofort increased the yield of plant significantly compared to control treatment.

Fig. 3:	Effect of organic manures on diseased yield (ton/fed.)

Fig. 4:	Effect of spraying with chitosan and aminofort on plant yield of tomato

Fig. 5:	Effect ofspraying with chitosan and aminofort on marketable yield of tomato

On the other side, spraying tomato plants with aminofort recorded the highest value of marketable yield/fed (44.32, 35.03% in the first and second seasons, respectively) without significant difference with spraying of chitosan wherein increased the marketable yield by 34.25 and 25.72% in both seasons over than the control treatment (Fig. 5).

Regarding the diseased yield, the data in Fig. 6 show that there were no significant differences among the treatments on diseased fruits yield/fed in the second season. While, in the first season the diseased fruits yield/fed. was significantly decreased with spraying of chitosan followed by spraying with aminofort. The highest fruit yield diseased was recorded by control treatment.

Fig. 6:	Effect of spraying with chitosan and aminofort on diseased yield (ton/fed.)

Fig. 7:	Effect of interaction between organic manures and spraying with chitosan and aminofort on tomato yield/plant

Effect of interaction between organic manures and spraying with chitosan and aminofort: It is clear from the data shown in Fig. 7 that the interaction between fertilization of tomato plants with goat manure with spraying chitosan and aminofort was the best interaction treatment for increasing yield/plant followed by spraying chitosan and aminofort with fertilization of FYM. The same trend was obtained with marketable yield/fed which is illustrated in Fig. 8. With regard to the diseased yield, data in Fig. 9 reveal that fertilization tomato plants with goat manure alone increased the impaired yield fruits/fed. without significant differences than spraying aminofort with fertilizing of the both organic manure sources in the first season. In the second season, fertilization of goat manure or FYM separately recorded the highest values of disorded fruit yield without significant differences with the other treatments, except spraying with chitosan alone which recorded the lowest value of disorded fruit yield/feddan.

Fig. 8:	Effect of interaction between organic manures and spraying with chitosan and aminofort on marketable yield of tomato

Fig. 9:	Effect of interaction between organic manures and aminofort on diseased yield (ton/fed)

Fruit quality
Effect of organic manures: Regarding fruit quality (pH and TSS), Fig. 10 shows that there were no significant differences among the organic manure sources on fruit quality. The treatments did not reflect any significant differences on fruit pH which recorded 4.11, 4.22 and 4.20 for control treatment, goat manure and FYM, respectively. Applications of FYM slightly increased TSS (7.02%) compared to goat manure (6.53%) and control treatments (5.96%).

Fig. 10:	Effect of organic manures on pH and TSS(%) of tomato fruits

Fig. 11:	Effect of spraying with chitosan and aminofort on pH and TSS (%) of tomato fruits

Effect of spraying with chitosan and aminofort: Figure 11 shows that spraying tomato plants with chitosan or aminofort did not reflect any significant effect on pH (4.19, 4.18) and TSS (6.61%, 6.54%) of tomato fruits compared to control treatment which recorded 4.16 and 6.36% for pH and TSS, respectively.

Effect of interaction between organic manures and spraying with chitosan and aminofort: It is clear from Fig. 12 that there were no significant differences among the interaction treatments on pH and TSS in tomato fruits.

DISCUSSION

Effect of organic manures: Fertilization of tomato plants with goat manure or FYM increased all different plant organs expressed in plant height, number of both branches and leaves/plant, the total fresh and dry weight of plant as well as the contents of chlorophylls (Table 2, 4 and 6). The positive effect of goat manure or FYM on vegetative growth may be attributed to the high content of nitrogen in both sources, respectively, and the other beneficial effects of organic manures on soil properties.

The increments in the above mentioned traits are higher with application of goat manure than FYM. This may be owed to the higher contents of nutrients compared to FYM (Reddy and Reddi, 2002).The increment in plant growth and the content of photosynthetic pigments may be attributed to the positive effect on sandy soil properties.

Fig. 12:	Effect of interaction between organic manures and spraying with chitosan and aminofort on pH and TSS(%) of tomato fruits

Application of organic manures change the organic matter input and it may affect on soil properties and crop depending on mineral nutrients supply and soil microbiological properties (Chirinda et al., 2008), increase in microbial activities, microbial-biomass, biomass C, N flush and consequently increasing the enzymes activities (Nur et al., 2006; Dinesh et al., 2000; Appireddy et al., 2008).The increment in plant growth due to application of organic manure ascribed to reducing in soil bulk density, increase porosity and moisture content as well as higher availability of macro and micronutrients in soils; viz, N, P, K, Ca , Mg, Fe, Zn, Mn, and Cu as a result of organic manure mineralization, reduction of fixation and complexing properties of these manures with macro and micronutrients (Rasoli and Forghani, 2006; Agbede et al., 2008).

Yield/plant and marketable yield/fed. were increased with fertilization of goat manure and FYM compared to control treatment (Fig. 1, 2). These results may be converted to the enhancement of plant vegetative growth due to application of organic manures wherein showed an increase in tomato plant healthy (Ghorbani et al., 2008), increasing in photo assimilation as a result of increasing in leaf area and dry weight of tomato plants (Azarmi et al., 2008). In this connection, Ghorbani et al. (2006) found that fertilizing tomato plants with cattle manure had high marketable yield compared to sheep manure. On the other hand, the both sources of organic manures; i.e., goat manure and FYM increased the diseased yield (Fig. 3). The increment in diseased yield was higher than with application of goat manure. This may be owed to the highest vegetative growth which need to supplemental of a lot of water quantities for the high vegetative and fruits growth under sandy soils. In contrast with Azarmi et al. (2008) who found that the occurrence rate of physiological disorder of blossom-end rot of tomato fruits was reduced with increasing in sheep manure vermicomposted rate in soil. The data pointed out in Fig. 10 illustrate that there were no significant differences among the organic manure sources on pH and TSS in tomato fruits. These results are in harmony with those reported by Azarmi et al. (2008), who found that addition of sheep manure vermicomposted to the soil had not significant effect on TSS and pH of tomato fruits juice.

Effect of chitosan: Spraying tomato plants with chitosan increased significantly all the vegetative growth traits of plant as well as the contents of photosynthetic pigments (Table 2, 4, 6). These results may be owed to antimicrobial effect of chitosan on pathogenics and microparasitic fungi (Abou Sereih et al., 2007; Palma-Guerrero et al., 2008) which caused a promotion of root hair (Gornik et al., 2008) and seemed good plant due to increments soil actinomyces and decreased filamentous fungus (Hitomi et al., 2006). Spraying tomato plants with chitosan increased the vigor plants, and this phenomenon was probably connected with bigger resistance of tomato roots fungi pathogenesis which had healthier roots (Borkowski et al., 2007). Table 2 showed that application of chitosan increased the number of leaves that may be attributed to the increment in internodes (Gornik et al., 2008).

Concerning the effect of spraying of chitosan on tomato yield, Fig. 4, 5 and 6 show increment in yield/plant and marketable yield/fed., and decreased the disorder yield/feddan.The increase in yield may be owed to the increment in photosynthetic pigments which led to the increment in the vigor growth and hence increase in yield. Regarding the disorder yield, the data in Fig. 6 reveal in the first season that, the diseased fruits yield/fed. was decreased significantly with spraying of chitosan followed by spraying with aminofort. The highest fruit yield diseased was recorded by control treatment. The decreasing of disorder yield due to application of chitosan might be due to the increment in lignification (Wojdyla, 2001).

Generally, it could be said that spraying plants with chitosan increased plant product as a result of stimulation of the immunity of plants (Wanichpongpan et al., 2001; Hadwiger et al., 2002; New et al., 2004) to protect plants against microorganisms (Pospieszny et al., 1991) and to simulation of roots, shoots, leaves and chlorophyll content and photosynthetic rate (Chibu and Shibayama, 1999; Khan et al., 2002; Gornik et al., 2008).

Effect of aminofort: Application of aminofort increased both total fresh and dry weight of plant as shown in Table 4 as a result of increasing in plant vegetative growth; viz., plant height, number of both branches and leaves/plant as well as increased the photosynthetic pigment in tomato leaves (Table 2, 6). The simulative effect of aminofort may be owed to the contents of amino acids, GA and other mineral nutrients.

In this respect, the abovementioned results are in agreement with Tantawy et al. (2009), who found that application of amino acids increased tomato plant height, leaf area of plants, fresh and dry weight of aerial plants, as well as total chlorophyll which reduced the percentage of barely albino plants (Ting et al., 1998). Also, amino acids improved plant growth and production under saline water (Abdel-Latif, 1995; Hafez, 2001).

The increment in marketable yield (Fig. 5) may be attributed to the increase in leaves chlorophyll content leading to increment in carbohydrate synthesis and consequently increment in plant production (Fig. 4). Application of amino acids increased pollen germination and the length of pollinic tube, leading to increment in fruit set %, average fruit weight, and yield/plant (Neeraja et al., 2005), but TSS was not affected significantly (Tantawy et al., 2009).