Diagnosis of abiotic and biotic stress factors using the visible symptoms in foliage

Visible symptoms in the foliage of trees are recorded to monitor the effects of abiotic and biotic stress. Difficulties are reported in diagnosing the origin of stress. The present paper discusses several diagnostic criteria which are usable in different species for a better determination of the stress factor type. A new diagnosis scheme to differentiate between classes of abiotic and biotic stress factors is supplied. Abiotic stress generates gradients of symptoms. The symptom specificity is determined by the degree of interaction between the stress factor and plant defense system. Symptoms caused by abiotic stress and natural autumnal senescence can be morphologically different or undistinguishable according to the stress and plant species. With biotic stress, the class of parasitic is generally recognizable on the basis of the visible symptoms. Structurally and physiologically based explanations of the symptom morphology are still missing for many stress factors.     

纳滤去除水中内分泌干扰物双酚A和四溴双酚A的研究

用死端过滤法考察纳滤膜Desal 5 DK处理水中内分泌干扰物双酚A(BPA)和四溴双酚A(TBBPA)的效率,并研究吸附对纳滤截留有机分子的影响.结果表明,纳滤膜Desal 5 DK对BPA的表观截留率随累积吸附量的增加而降低,从初始的89%降至达到平衡状态时的47%,BPA累积吸附量相应达到约30 μg·m-2.较高压力时,吸附层较高的溶质浓度引起膜通量下降.虽然Desal 5 DK对TBBPA累积吸附量达到50 μg·m-2,但由于分子量较大和分子结构复杂,截留率较高(>95%).5×105 Pa压力下解吸时TBBPA分子由于位阻效应几乎不能透过纳滤膜;而BPA则扩散通过纳滤膜,并且在流出30 mL时浓度达到峰值,流出的BPA总量约占总吸附量的30%.     

Are Artificial Barrages Necessary to Prevent Saline Incursion? A Modelling Approach to Restore the Healthy Ecosystem of the Vembanad Lake

Environmental Modeling & Assessment - The Thanneermukkom Bund was constructed to prevent salt water intrusion in the low lying areas of the Kuttanad region which increase the paddy cultivation...