The Effect of Water and Salt Stress on Paspalum dilatatum,a Constituent of Pampas Natural Grasslands

The effects of the salt stress on plant growth are usually increased by the water stress.We studied the impact of both stresses in simultaneous pulses of drought and salinity on Paspalum dilatatum.This forage species is native to South America,spread in grasslands in many tropical,subtropical,and temperate areas of the world,and very common in grasslands of the Flooding Pampas of Argentina.Mimicking what happens in nature.We compared a pot experiment,a non-stressed control against water stress for a month(midpoint between field capacity and wilting point),and two saline stresses(moderate,6 d·Sm^(−1)and strong,12 d·Sm^(−1)),also for a month.Aerial biomass(green leaf;non-leaf green material,and dry material)and roots were harvested,weighed,and analyzed for nitrogen,phosphorus,and cations.The biomass of all components significantly decreased when both stresses were applied.Water plus strong saline stress reduced by half the total biomasses,compared to the control.The proportion of aerial biomass/root biomass ratio as well as aerial green component/dry materials ratio tend to decrease when subjected to both stresses.Nitrogen concentration in plants was not significantly affected,but phosphorus concentration increased in aerial biomass components,from 0.10 to 0.18 mg·kg^(−1)between the extreme treatments,but did not change in roots.Sodium concentration in plants increased(i.e.,in green leave sodium(Na)increased from 0.27 to 2.01 mg·kg^(−1)between the extreme treatments),whereas other cations either did not change or decreased,affecting the ratios between them.Sodium performance allows us to infer that the Na accumulation of P.dilatatum behaves in an intermediate range,compared to very tolerant to salts or non-salt tolerant species of the Paspalum genus.In agreement,when salts were applied in the form of a pulse,P.dilatatum tolerated higher salinity than that found by other authors for the same species,using continuous salinity.

世界礼仪皇后Miss Dally在大连诠释礼仪 优雅是永恒不变的时尚

1月17日,世界礼仪皇后、JDW商学院创始人,世界殿堂级明星June Dally Watkins空降大连,一场顶石珠宝之行从此开启。 Miss Dally今年已经88岁了。她和奥黛丽·赫本是闺蜜,与玛丽莲·梦露是好友。她是英国女王钦准的礼仪皇后,被她培养出的优秀学生有40万,其中包括妮可·基德曼和米兰达·可儿。