Physiologiacl studies on effect of foliar application of some micronutrients and ascorbic acid on tuberose "polianthes tuberosa l.," plantes grown on a saline calcareous soil

الملخص EN

A filed experiment was conducted to study effect of foliar spray with some micronutrients (Fe, Zn, Mn and Cu) at three concentrations, i.e., 50, 100 and 150 mg / L for each or ascorbic acid at four concentrations, i.e., 100, 200, 300 and 400 mg / L added alone or together on vegetative growth, flowering, oil yield and some chemical constituents of tuberose (Polianthes tuberosa L.) plants grown on a saline calcareous soil.

The obtained data indicated that, all growth parameters, i.e., leaf length, leaf area, number of leaves / plant, fresh weight of leaves, dry weight of leaves were significantly increased as a result of foliar spray with micronutrients and ascorbic acid as solely or combined treatments.

In additions flowering traits, i.e., flower stalk length, number of florets /spike, spike length, fresh weight of spike, dry weight of spike and number of spike per plot exhibited pronounced increase.

Moreover, bulb diameter, fresh weight of bulb, number of new bulblet / plant and essential oil percentage of florets were also increased.

The maximum increases in the former parameters were resulted from using micronutrients at the rate of 150 mg / L and ascorbic acid at the rate of 300mg / L alone or combined together.

The same rates of micro-nutrients and ascorbic acid also led to increase the concentrations of chlorophyll a & b, caroteniods, total carbohydrates, total & reducing sugars, total indols, total free amino acids, free proline, N, P, K, Fe, Mn, Zn, Cu and vitamin C in leaves .At the same time, the activity of oxidative enzymes such as peroxidase, catalase, polyphenol oxidase and ascorbic acid oxidase were recorded the highest values by spraying with the same rates of micro-nutrients and ascorbic acid alone or together.

On the other hand, the applied treatments decreased the concentrations of sodium and free phenols in leaves.

In view of these results, it has been concluded that spraying tuberose plants with the mixture of micronutrients (Fe, Mn, Zn and Cu) and ascorbic acid at the rates of 150 and 300mg / L, respectively could be counteracted the adverse conditions, particularly soil salinity and consequently producing economic flower and oil yields.