Roots and leaves of Panicum maximum Tanzânia, Mombaça and Massai; Urochloa brizantha Piatã, Marandu and Xaraés; Urochloa humidicola Llanero; Urochloa ruziziensis Ruzizienses; Urochloa hybrida Mulato II and Cynodon nlemfuensis Estrela-roxa were analyzed, seeking to identify characters for better adaptation to the environment that may interfere with digestibility of tissue from the point of view of the rumen in cattle. Were planted ten cultivars in a completely randomized blocks with three repetitions. Was collected vegetative material, which histological slides were prepared from middle third of the sections of roots and leaves. Were observed differences (p>0.05) in the roots: higher volume of epidermal cells (28.62 µm) and overall diameter (1926.41 µm) of Llanero; thicker vascular cylinder (975.09 µm) and more protoxylem (42.25) in Estrela-roxa and occurrence of aerenchyma in cultivars Piatã, Mulato II, Xaraés, Massai, Llanero and Estrela-roxa; Were found higher proportions of bulliform cells in the leaves (121.07 µm) and thicker leaf mesophyll in U. humidicola Llanero (263.63 µm); higher proportion of sclerenchyma fibers in Xaraés and Marandu; lower results for amount of fibers in P. maximum Massai. We conclude that the cultivars Estrela-roxa, Llanero and Massai have greater adaptability to the environment and better nutritional quality. Keywords

Water scarcity has become one of the main global problems, since of all the water of the terrestrial surface, only 2.5% represents fresh water, and of this, only 0.3% corresponds to the water of the rivers and lakes that are available to supply the demand for food production and other uses. The present work consisted in surveying the scenario related to the global water crisis and presenting evidence that even Brazil being abundant in the amount of water available, tends to face serious problems because of its scarcity, affecting two of the main economic pillars, agribusiness and industry. It was observed that the main negative effects on water resources occur due to urban occupation and agricultural practices in a disorderly way, causing destruction of natural resources through the discharge of domestic sewage, industrial effluents and agrochemicals. In general, the lack of control of the use of the water directed to the productive processes is one of the major generators of the water shortage, since 69% of the water derived from rivers, lakes and aquifers underground is turned to irrigated agriculture, using 70 times more water than for domestic purposes. Thus, it is necessary to adopt policies aimed at the conservation and efficient use of water resources, to value water as a social, social and environmental good, since their scarcity can generate instability in economic sectors such as agriculture, generating production insecurity in industry, as well as affecting the supply of drinking water, basic sanitation and public health.

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