Response Of Paspalum And Ryegrass Plants To Sea Water

Abstract

Salinity refers to the occurrence of various salts in soil or water in concentration that may interfere with the growth of plants, Turfgrass species and cultivars differ in their responses to salinity, a number of researches were conducted to determine the effect of salinity on growth and development of turfgrass, this study was conducted to examine the effect of different sea water concentration on seed germination and development of Perennial Ryegrass (LoliumPerenne L.) and Knotgrass (Paspalum Distichum), for seed germination study of Perennial Ryegrass(Lolium Perenne L.), seeds were grown in petridishes lined with filter paper moisten with saline water in different concentrations (0%, 1%, 2%, 5%, 10% and 20%) irrigated with same solutions for two weeks. Parameters like seed germination, mean germination time, shoot and root lengths were measured in 3 replicated pattern, for Knotgrass (Paspalum Distichum) development study, seeds of Knotgrass (Paspalum Distichum) were grown in pots and irrigated with saline water in the same concentrations and parameters like fresh and dry weights of shoot and root system, in addition to leaf water contents were measured. The results of seed germination study revealed that germination of Perennial Ryegrass (Lolium PerenneL.), decreased with increased salinity, xv mean germination time delayed with increased salinity level, shoots and roots weights decreased with increased salinity and the differences in the means of roots and shoots lengths was significant compared with the control treatments. The results of seed development study of Knotgrass (Paspalum Distichum) revealed that, there was no correlation between salinity and leaf water content and the differences in the mean of leaf water content was not significant (p- value 0.036), effect of salinity on fresh and dry weight of shoot system was significant(p-value 0.008 0.015) respectively but fresh and dry weights of root and shoot systems was not significant (p- value 0.083, 0.095) respectively. The results of seed germination showed that Perennial Ryegrass (Lolium Perenne L.) tolerate salinity very well it can tolerate salinity to (10% and 20%). While the Knotgrass (Paspalum Distichum) showed very weak tolerance to salinity. 1 Chapter One 1. Introduction. Potable water is essential for human survival. With the progression of climate change and unpredictable weather conditions, the United States has experienced significant areas of drought over the last decade (Schiavon et al. 2013). One of the most urgent problems in many of the arid and semi-arid countries is the scarcity of water and Libya is among these countries. Finding enough water to support the food needs and other demands is a priority to all governments. Availability of good quality irrigation water is always a constraint in the arid regions and the water desalination is an expensive alternative. In addition, due to the increased pumping of saline water from the deep wells, the level of total salinity in the soils has increased. Libya is one of the driest countries in the world with significant changes recorded in temperature and precipitation during the last couple of decades, within which roughly 90.8% of the area is hyper-arid, 7.4% arid, 1.5% semi-arid and 0.3% is classified as sub-humid (Ben-Mahmoud, 1993); with the sub-humid region located in northeast. Libya as an arid nation accounts for 94.5% areas as desert with perpetually scarce freshwater except for a narrow strip along the northern coast, which has a Mediterranean climate. Barely 5% of the country receives more than 100 mm of rain each year. Libya since long relies on groundwater reserves to meet its needs. However, surging demand is stressing supply, and many coastal groundwater aquifers are becoming brackish with an influx of seawater. Thus a major environmental concern in Libya is the depletion of underground water as a result of overuse mainly in agricultural developments, causing salinity and sea-water penetration into the coastal aquifers (Bindra et al., 2013). 1.1. Green fields turfgrasses and their importance: In modern urban living , turfgrasses play significant role in enhancing quality of life. They