Experimental Study On Several Kinds Of Representative Plants Under Factory Cultivation

With the development of economy and the progress of society,people's awareness of environmental protection has become stronger and stronger,and the quality requirements for green and pollution-free products have become higher and higher.However,the rapid development of industry and urbanization,and the large-scale use of chemicals such as pesticides and pesticides have caused more and more serious agricultural pollution.These pollutants flow from plants into animals through food chains,resulting in biological enrichment,and then harm human health.Plant industrialization cultivation mode which has many advantages came into being.This article choosed three strong representative plant species called Lactuca sativa L.var.ramosa Hort,Metasequoia glyptostroboides,and Salix matsudana that cover the main plant species of herbs,woody gymnosperms and woody broad-leaved plants.A indoor multi-layer hydroponic and matrix culture system was constructed to simulate the conditions of plant factories.Preliminary studies were conducted on the nutrient solution management of L.sativa,the breeding of M.glyptostroboides,and the restoration of polluted water bodies byS.matsudana.The results are as follows:1.The effects of different nitrogen treatments(5 mmol.L^-1 NO₃^--N,10 mmol.L^-1 NO₃^--N,5 mmol·L^-1 NO₃^--N + 5 mmol.L^-1 NH₄⁺-N)on the growth and physiological characteristics of L.sativa were studied.The results showed that after 35 days,NH₄⁺-N inhibited the growth of L.sativa with the same nitrogen concentration.The leaf area,plant height,aboveground fresh weight,aboveground dry weight,underground fresh weight and underground dry weight decreased by 78.2%,60.4%,87.0%,81.3%,80.1%and 87.5%respectively?p<0.05?.In addition,there were significant differences in their physiological activities such as root activity,soluble protein,superoxide dismutase activity and nitrate reductase activity?p<0.05?.Compared with 10 mmol·L^-1 NO₃^-1-N?12.89 g?,the biomass of L.sativa reduced slightly with the treatment of 5 mmol·L"1 NO₃^--N?8.90g?,and the leaf area,root length and underground dry weight decreased by 48.1%,50.3%and 37.5%respectively?p<0.05?,but the content of soluble sugar and anthocyanin increased by 67.5%and 51.9%respectively?p<0.05?,while the ratio of NO₃^--N uptake reached the maximum on the 21st day,which is 3.15 times of the former.Our results showed that L.sativa was a nitrate-love vegetable,and the optimum concentration of nitrate in L.sativa was high(10 mmol·L^-1)in early prophase?before 21 days?in order to promote the growth of butter lettuce,but later?after 21 days?low concentration nitrate(5 mmol·L^-1)was recommended to improve quality of butter lettuce.2.The study was conducted on the rooting and survival status of M.glyptostroboides cuttings under hydroponic and substrate culture conditions.The results showed compared with the substrate culture,the M.glyptostroboides cuttings grew better in hydroponic conditions,that is,the industrialized hydroponic conditions were more suitable for the growth of M.glyptostroboides cuttings.Under water culture conditions,there was no significant difference?p>0.05?of shoot length,root length,and belowground fresh weight in M.glyptostroboides cuttings from maternal trees of different ages.M.glyptostroboides cuttings from 7-year-old maternal trees had the maximum length of shoots?9.83 cm?and maximum belowground fresh weight?1.42 g?,while from 10-year-old maternal tree had the longest root length?12.83 cm?.In addition,the number of buds of M.glyptostroboides cuttings from 2-year-old maternal tree?7.00?was significantly greater?p<0.05?than that of 7-year-old maternal tree?2.33?and 10-year-old mother tree?2.67?.But the root number?9.67?and fresh aboveground weight?3.87 g?of M.glyptostroboides cuttings from 7-year-old maternal tree were significantly higher?p<0.05?than that from 2-year-old maternal tree?2.50 in root number and 1.62 g in aboveground weight?.In summary,the cuttings from 7-year old maternal tree had a better growth status.The results of the study showed that industrialized hydroponic management could let M.glyptostroboides cuttings grow more roots,and can be rooted in large areas,and then the rooted M.glyptostroboides cuttings are transplant to soil conditions,which is of great significance for the preservation of the precious tree species M.glyptostroboides.3.This study investigated how nitrogen?N?and phosphorus?P?fertilization alter the toxic morpho-physiological impacts of and accumulation of Cd in hydroponically grown S.matsudana cuttings.We found that Cd significantly depressed growth and induced a physiological response on S.matsudana cuttings,exhibiting by reduced biomass,decreased photosynthetic pigment concentrations,and increased soluble protein and peroxidase activity of shoots and roots.N and P fertilization alleviated the Cd toxic effects by increasing production of proline which prevented cuttings from damage by Cd-induced ROS,displaying with decreased malondialdehyde concentration,and stimulated overall Cd accumulation.The improved phytoextraction potential by N and P fertilization was mainly via elevating Cd concentration in roots.Additionally,significant N and P accumulation,which was enhanced by Cd addition,was observed in S.matsudana cuttings,suggesting they were also helpful for N and P removal.This study provides support for the application of S.matsudana in Cd phytoextraction even in eutrophic aquatic environments.In summary,the present study showed that L.sativa is a nitrate-love vegetable under industrialized hydroponic conditions.At the early stage,high concentration nitrate should be provided to promote the growth,while at the later stage,low nitrate level was recommended to improve the lettuce quality;The M.glyptostroboide cuttings from 7-year-old maternal tree are better than other maternal tree,and it is the 1 optimal age of maternal tree for factory cultivation of M.glyptostroboide;increasing N and P supply will enhance the ability of S.matsudana cuttings to enrich Cd.