half lethal concentration

The half lethal concentration of 48? h-LC_ ( 50) of 21 nitrobenzenes to Daphnia carinata was determined by use of the standard test method, and the range of toxicity was from 3.49 for nitrobenzene to 5.40 for 1,4-dinitrobenzene.

采用标准实验方法测定了21种硝基苯类化合物对隆线蚤（Daphnia carinata）的48h半致死浓度值，结果lg（1/LC50）的范围在349～540之间；

Through experiments have found that: when the concentration of heavy metals in the soil is 0.5 percentages, it fits the half lethal dose.

通过实验发现：当土壤中重金属的含量为0.5%时，最符合蚯蚓的半数致死量。

It is summarized that the seedling's tolerance of half lethal salt concentration, the seed vigour index, and the seed nitrogen content could be regarded as the physiological index for assessing the level of the seed salt tolerance and whether it be selected for breeding.

初步认为种子耐盐半致死浓度、种子活力指数和含氮量可以作为种子耐盐性评价和选育的生理指标。

Lethal concentration ( LC50) The water in the lake is comparatively cold and the lake remains frozen half of the time each year.

半致死浓度（LC50）池水温度较低，一年中有半年冰封期。