Characteristic Of Formaldehyderemoval And Physiological Indexes Of Plantsin Fumigation System

Formaldehyde is an important indoor pollutant,and the effective removal of indoor formaldehyde has been always a research hotspot.Among the many methods,the technology of phytoremediation has been widely used,which is economical,beautiful and efficient.In this study,the dynamic fumigation system has been improved on-line monitoring which based on the static fumigation system.At the same time,the fumigation test of three different varieties of spider plant(Chlorophytum comosum(CC),Green Chlorophytum comosum(GC)and Purple Chlorophytum comosum(PC))was extended to successive 7 days,then the ten physiological indicators were determinated and microscopic stomata were observed.The removal rate of different time periods(day(6:00-18:00)and night(18:00-6:00),morning(6:00-12:00)and afternoon(12:00-18:00),pre-period(first three and half day)and post-period(later three and half day))were also analyzed.The resulted shown that the relative conductivity of leaves was increased while chlorophyll content was decreased with the increased of formaldehyde concentration within the static fumigation system.Moreover,the stomatal morphology were changed and the indexes were varies.Maybe the tolerance and purification ability of the Spathiphyllum was stronger than Murraya.In addition,the removal of formaldehyde by CC was the highest and PC was the weakest within the dynamic fumigation system.And the removal rate decreased with the formaldehyde increased(1ppm,5ppm and8ppm),which were 73.88%,64.73% and 38.19% of CC,54.41%,8.15% and 30.71% of GC,41.11%,32.53% and 31.01% of PC,respectively.The removal rate was different in different periods of fumigation test,which was significantly higher in the daytime than at night,in the afternoon was higher than the morning,and in the post-period was higher than in the pre-period,but the PC was on the contrary.In addition,there was a high correlation between removal and humidity and temperature in the environmental,because the formaldehyde is easily soluble in water that is beneficial to the plants to absorb.In the analysis of the physiological index of the leaves,except the chlorophyll,protein and CAT,others were all increased.Compared with the control group,the changes of CC was the greatest while the PC was lowest.So that,the order of tolerance to formaldehyde from strong to weak was CC > GC > PC.The resistance and self-healing ability of the plants were strong.After fumigation with formaldehyde,mostof the physiological indicators could be repaired within 15 days,except the POD and T-AOC of PC.The repair time of CC was the shortest.So the resistance of CC was the strongest and the PC was the weakest.Through the determination of physiological indexes,it was found that the toxic effect of formaldehyde on plants was mainly caused by oxidation,which resulted in excessive accumulation of oxide.On the other hand,the resistance to formaldehyde was due to removal of accumulated oxides through the antioxidant system which could maintain the plant growth normally.Finally,the removal rate was analyzed again on the second fumigation experiment.The results shown that,with the formaldehyde increased,the removal of CC was40.20%,38.30% and 33.72%,and GC was 36.85%,24.67% and 20.14%,while PC was30.25%,17.51% and 11.18%,respectively.The varies of the removal maybe because of the difference season.As the result of the first test,the removal rate of night was lower than the daytime,the morning was lower than the afternoon.However,the removal of the pre-period was higher than the post-period which in contrast to the first fumigation experiment.The reason may be explained by that the first fumigation experiment has raised the adaptability and the purification ability of the plants within the formaldehyde environment.It shown that proper pretreatment of plants can enhance the resistance and improve the purification capacity of pollutants.