JWSS - Journal of Water and Soil Science

---

The interference of biological agents may cause behaviors such as interspecific predation, reducing their efficiencies. The interspecific predation of lacewing, Chrysoperla carnea (Steph.) and ladybeetle, Hippodamia variegata (Goeze) was investigated in the presence and absence of prey, Aphis gossypii Glover under laboratory conditions.

In the presence and absence of prey, the larvae of lacewing fed on eggs, larvae, pupae and adults of ladybeetle and the larvae and adults of ladybeetle fed on eggs and larvae of lacewing. Presence of prey reduced the rate of feeding significantly. Feeding of lacewing larvae on ladybeetle eggs was higher than the feeding of ladybeetle larvae and adults on lacewing eggs. This is probably due to the stalk of lacewing eggs. The 1st larval instar of lacewing was dominant to that of ladybeetle, so were 2nd larval instar of lacewing to the 1st and 2nd larval instars of ladybeetle and 3rd larval instar of lacewing to all larval instars and adults of ladybeetle. Third larval instar of ladybeetle was dominant to the 1st larval instar of lacewing, and 4th larval instar and adult of ladybeetle to the 1st and 2nd larval instars of lacewing. The 2nd and 3rd larval instars of lacewing fed on pupa of ladybeetle but larval feeding of ladybeetle was not observed on lacewing pupa. This was probably related to lacewing pupa covered by a cocoon.

---

Low calorie salad dressings are oil-in-water emulsion products, in which the oil content has been substantially decreased. This decrease, however, is accompanied by reduction in the viscosity hence, an undesirable texture. To overcome this, oil replacers are generally used. In this research, maltodextrin and xanthan gum were used to replace part of the oil in the production of two kinds of salad dressings mayonnaise and three Italian salad dressing. Various formulations of these products with varying amounts of oil, maltodextrin and gum at different temperatures were produced. Viscosities in the range of 50-140 Pa.s for mayonnaise and 2-15 Pa.s for Italian dressing were accepted as positive criteria and samples in these ranges were chosen for organoleptic and microbial tests. The results showed that in the formulation of mayonnaise, simultaneous increase in the amount of oil, maltodextrin and gum created a high viscosity, but the temperature did not play any significant role. In the Italian salad dressing, the increase in the amount of gum was accompanied by development of pseudoplastic characteristics which was not desirable, hawever, the effect of temperature on providing acceptable texture was found to be important. Although the formulated mayonnaise enjoyed a fairly acceptable quality, the Italian salad dressing samples, were ranked superior to the common Italian salad dressing available in the Iranian market. .

---

Studies show that excessive rotation of rice, when the grains revolve inside the milling chamber, increase the breakage. Ease of grain movement in the milling chamber could minimize this problem by utilizing screw conveyor at the first part of rotor. In this study the rotor of a conventional milling was equipped with a screw conveyor. The effects of two rotor types (modified and conventional rotors), three output rates (412, 654 and 915 kg/h) and three blade distances from the agitator (11, 12 and 13mm) were examined on indices of rice quality using a split-split plot design. In this experiment, the percentage of whole white rice and breakage, degree of milling and milling performance index were either measured or calculated. Results showed that only the effect of blade distance on percentage of breakage was significant whereas the effect of feed rate on all measured parameters was significant. In addition, the interaction effects of rotor type and blade distance, rotor type and feed rate on percentage of whole white rice and breakage were significant, respectively. The milling performance index showed that the best conditions for both rotors can be obtained at output rate of 412kg/hr and 11or 12mm blade distance from the agitator. For this adjustment, the average of percentage of breakage in the modified and conventional rotors were 20.5 and 23, respectively.

---

Boston fern (Nephrolepis exaltata Schott cv. Bostoniensis) is an ornamental foliage plant considered today as one of the most marketable indoor pot plants. Due to the restriction of conventional propagation methods, mass propagation of this plant has increased through in vitro culture techniques. In the present study an attempt has been made to achieve the best medium for runner tip culture of Nephrolepis. At first, runner tips were disinfected by using 15% commercial bleach (5.25 % sodium hypochlorite) for 15 minutes. After that, explants were inoculated on 12 different initiation media using two concentrations of Murashige and Skoog (MS) mineral salts (1/2 MS and 1/4 MS), two concentrations of sucrose (20 or 30 g/l) and three concentrations of benzyladenine (BA), (2, 1 and 0.5 mg/l). The experiments were conducted in factorial arrangements in a completely randomized design with 4 replications. The number and height of shoots were measured after 6 weeks. During the experiment period, quality characters and time of leaf perimordia emergence and green globular body (GGB) formation were measured. The highest number of shoots with low height was achieved in media consisting half concentrations of MS mineral salts, 30 or 20 g/l sucrose and 1 or 2 mg/l BA. GGB formation also occured on media consisting 1 and 2 mg/l BA at all treatments. Microscopic investigations of GGB showed that they contain adventitious buds. Medium, containing ½ MS, 20 g/l sucrose and 1 mg/l BA was found to be the best.

---

Defining interrelationship of growth analysis factors and yield of crop plants is important in the field crop production practices. This research was aimed at studying growth factors and grain yield of five maize hybrids, consisting of S.C.704, S.C.700, S.C.647, S.C.604, and S.C.301, using two 4-replicate RCBD experiments in Isfahan, in Summer 2004. While one experiment was irrigated normally, the other one was conducted under delayed irrigation conditions. Maize plants were seeded at 95000 plants/ha in 8-row plots, with rows spaced 0.70m apart and 0.15m distance between plants on each row. Delayed irrigation led to a significant decrease in LAI_max, LAD, LAD_Linear and LAD_s-m, but a significant increase in days to silking. While CGR_Linear significantly correlated with LAI_max, LAD, LAD_Linear and LAD_s-m, a significant correlation was observed between total biomass and grain yield. CGR_Linear, LAI_max, and LAD_s-m significantly correlated with total biomass, and grain yield significantly correlated with yield components, harvest index, CGR_Linear and LAI_max. In conclusion, an increase in LAI_max resulted in a higher CGR_Linear and in turn a greater total biomass. But, considering no significant correlation between total biomass and harvest index, it appears that with the genotypes and under conditions of the present study, allocation of dry matter to grain production did not correlate with the leaf area attributes of corn.

---

Rice whitening is an important stage in rice milling process and improvement of the whitener machines has a remarkable effect on rice loss. To decrease the amounts of broken rice and losses, the rotor of the blade whitener was equipped with screw conveyor. To investigate the effects of rotor speed (in four levels: 600, 700, 800 and 900 rpm) and output rate (in three levels: 400, 500 and 600 kg/h) on quality of milled rice, a factorial design with randomized complete block experiments with three replications were conducted. In this study, Sorkheh variety (a medium rice variety), which is one of the prevailing varieties in Esfahan, was used. The results showed that the lowest breakage percentage (20.92%) occurred at rotor speed of 700 rpm with an output rate of 600 kg/h and the best degree of milling (6.33%) took place at rotor speed of 600 rpm with an output rate of 400 kg/h. The best rice quality (low broken rice and high degree of milling) was observed at rotor speed of 600 rpm with 500 kg/h output rate.

---

Leaf chlorosis during both green house forcing and postharvest have been a long standing problem in Easter liliy. The symptoms typically start in the basal leaves and moves progressively upward and reduce flower quality and economic value of crop. In order to delay leaf chlorosis and increase vase life, an experiment was carried out on Asiatic hybrid Lilium cv Canova to study different treatments of benzyladenine (BA) and silver thiosulphate (STS) on pre and postharvest attributs, respectively. The results showed that preharvest application of BA effect the chlorophyll content of leaves significantly, but itُ s effect on stem and pedicle length and harvest time were not significant. Treatment of 0.44 mM BA on increased chlorophyll content greater than another treatments. In postharvest study, factors of 0.44 mM BA on chlorophyl1 content of leaves and leaf longevity, treatment of 0.88mM BA+ 0.6 mM STS on vase life, total soluble solids and uptake solution had most effect. The results showed that application of STS and BA can be used to prolong vase life, delay leaf senescence and enhance postharvest quality of lilium cut flowers during their transport market.

---

Salad dressing is a semisolid emulsion and a colloidal system with high consumer demand. Food polysaccharides (e.g starch) are used in the formulation of salad dressing to improve its physical properties and sensory attributes. In this research, 10% mixture of wheat or maize starches were used to produce pregelatinized starches by a double drum drier, followed by milling and sieving. The pregelatinized starches (10%) were applied in the formulation of a salad dressing instead of native starch. Viscosity (at 25 and 35◦C), Hunter color parameters of the samples were evaluated and compared. Pregelatinized starches were more effective in increasing viscosity of the samples compared to corresponding native starches, and the effect of maize starch was greater than wheat starch. Significant differences were recorded in terms of color parameters of the samples. Pregelatinized starch caused higher L values (lighter samples) while the native starch samples were creamy-light yellow. In general, it can be concluded that the pregelatinized starches had better functional properties in salad dressing compared to native starches, and the produced pregelatinized starches can be used instead of native starch in the formulation of salad dressing.