Grafting for the use of root systems as biological filters to prevent contaminants' penetration into vegetable plants.
A major part of the Mediterranean region is characterized by water scarcity, with long dry summers and short wet winters. To satisfy the demand for food Penetration with vegetable to combat desertification in this region, marginal water sources, such as treated domestic sewage effluent and saline water, are being increasingly used for irrigation Ben-Hur, Moreover, the pressure to avoid disposal of nutrient-rich effluents into water bodies has contributed to the rapid expansion of effluent reuse for irrigation Halliwell et al.
Similarly in effluents, the EC and pH values, and the concentrations of microelements such as heavy metals and B, and of nutrients and dissolved organic matter are, in general, significantly higher than in fresh water. Long-term use of these types of water for irrigation could increase the accumulation and concentrations Penetration with vegetable microelements and saline elements Na, Ca, Mg, and Cl in the soil Ben-Hur, ; Feigin et al.
Absorption of these elements by the plants could affect their growth and yield, and increase the possibility of contaminants entering the food supply chain. Consumers are becoming increasingly concerned about because of the possible adverse effects on environmental quality and human health.
This Penetration with vegetable particularly true forwhich are often regarded as a safe and nutritious food source. The effects of plant grafting on microelement concentrations in the fruit of melon plants under field conditions were studied in field plots with clay soil.
The field plots were irrigated with secondary effluent for 4 years, and melon non-grafted plant and grafted plant were grown in these plots. The concentrations of various microelements in the fruits of the grafted and non-grafted melon plants are presented in Fig.
To determine the mechanisms responsible for the lower microelement concentrations in the fruits of the grafted plants, detailed experiments were conducted in the greenhouse. B can be Penetration with vegetable by the root cell symplast or loaded into the xylem by means of two main transport mechanisms: To determine the differences in selectivity of the root systems of melon and pumpkin TZ to B absorption, their seedlings were planted in pots in the greenhouse, and irrigated with fresh water containing various concentrations of B.
Thirty days after planting, and immediately after an irrigation event, stems 3 cm above the surface of the growth medium were cut and the xylem sap exudates collected. B concentration was determined in each collected sap sample.
The B concentrations in the melon sap exudates were higher than those in the pumpkin sap exudates Fig. Thus it was postulated that the pumpkin root system was more selective and absorbed less B than of the melon roots.
The B-exclusion hypothesis is supported by other studies: The plasma membrane and partly through proteinaceous channels. Dordas and Brown examined B transport in squash plants, and suggested that both of these mechanisms were possible.
Vegetative growth, fruit yield and fruit sizes of the grafted plants were higher than those of Penetration with vegetable non-grafted plants Fig. The differences in yield parameters were probably due to Penetration with vegetable higher salt tolerance of the grafted vs. Likewise, Romero et al.
The concentrations of Ca, Na, Mg, and Cl- in the leaves, stem, and fruit tissues of a non-grafted melon cv. Arava plant and melon grafted onto pumpkin rootstock TZ grown in field plots in the experimental station in Akko are presented in Table 1.
These plants were irrigated with secondary effluent. The concentrations of all saline elements except Mg in the stem and leaves were higher in the non-grafted vs. The largest difference between the non-grafted and grafted plants was in their Penetration with vegetable concentration, which was one order of magnitude lower in the grafted plant tissues than in the non-grafted ones.
Two mechanisms might explain the decrease in shoot Na concentration in plants with pumpkin rootstocks: Quantitative analysis performed by Edelstein et al.
Na retention by the pumpkin rootstocks decreased its amount in the shoot by an average In contrast, no retention of Na was found in plants grafted on melons. Intensive agriculture has increased the use of toxic chemicals on cultivated lands.