RESPONSE OF CONOCARPUS ERECTUS L. PLANTS GROWN ON SANDY SOIL TO HYDROGEL APPLICATION UNDER DEFICIT WATER CONDITIONS

Water deficit is a main factor of limiting the growth of plants, particularly in arid and semi-arid regions. So this study was conducted in order to assess the influence of applying hydrogel polymers to minimize the negative effects caused by deficit water. Hence, An experimental pots was carried out during 2017 and 2108 seasons at the nursery of Sakha Horticultural Research Station, Horticultural Research Institute, Agricultural Research Center to study the effect of tow irrigation intervals (4 and 8days) and four hydrogel rates (0.0, 0.2, 0.4 and 0.6 % g/g) and their interactions on the growth traits and nutrition status of Conocarpus erectus L. plants as well as some soil properties were investigated. The obtained results point out that, growth parameters (plant height, number of shoots and leaves/plant and stem thickness, shoot fresh and dry weight and total green color) as well as the leaf mineral contents were significantly increased when buttonwood seedlings were watered every four days than when they were watered every eight days in both season. Conversely, leaf proline content was increased under irrigation every 8 days. in addition, adding hydrogel at 0.4 or 0.6 caused a significant increase in the previous growth aspects but decreased leaf proline content compared to the control. Both low irrigation period (4 days) or high of hydrogel rate (0.6% w/w) and their interaction gave the highest values of leaf total and free water contents as well as bound water and osmotic pressure were reduced. Finally, the largest rates of the hydrogel amendment (0.4 and 0.6%) under irrigation every 4 or 8 days extended the loss of soil water, increased the plant ability reflected in the accessible soil water and thus enhanced the growth parameters of the seedlings.