Study On Influence Of Duckweed’ Starch With Different Plant Growth Regulators

Oil energy shortage is common. bio-ethanol raw material is complex. So the use of duckeed to produce fuel ethanol has become research hotspot in China and abroad. Because starch in duckweed can quickly accumulated in certain conditions. Change mechanism of starch content in duckweed determines if the duckweed can be feedstock for ethanol.The study materials is Lemna aequinoctialis. Adding different plant growth regulator, such as abscisic acid, forchlorfenuron and paclobutrazol will change starch content of duckweed. In order to analyze the change mechanisms of starch content, it need to measure the chlorophyll content, superoxide dismutase(SOD) activity, peroxidase(POD) activity and starch degradation enzyme(α-amylase and β-amylase) activity. Experimental results are as follows:(1)Under effect of three kinds of plant growth regulator, Low concentration of plant growth regulator can promote growth of duckweed in a short time. High concentrations of experimental group have strongly inhibitory action on duckweed growth.(2)Chla and Chlb content declined slowly in different concentration of abscisic acid. Under action of forchlorfenuron in low concentration(10 mg/L,20 mg/L,40 mg/L),chlorophyll content changed little. Under action of forchlorfenuron in high concentration(80 mg/L,100 mg/L), Chla and Chlb content decreased gradually. Under action of paclobutrazol in low concentration(50 mg/L、100 mg/L), Chla and Chlb content increased slightly. Under action of paclobutrazol in high concentration(200 mg/L,400 mg/L,600 mg/L), Chla and Chlb content declined slowly.(3)Under effect of three kinds of plant growth regulator, SODand POD activity increased at early stage and dropped gradually at late satage. α-amylase and β-amylase activity decreased constantly,which can prevent duckweed internal starch degradation, and content of starch increased under effect of three kinds of plant growth regulator. Eventually starch content percentage is 20% ~ 24%.(4) Duckweed grows well in 10-9 ~10-7 mol/L concentration of abscisic acid. Cultivation of duckweed best control within 6 days. Accumulation of starch content compared with the blank increased by 209%, 250% and 264% respectively. Duckweed grows well in 10 ~40 mg/L concentration of forchlorfenuron. Cultivation of duckweed best control within 8 days. Accumulation of starch content compared with the blank increased by 280%,296%,314%. Duckweed grows well in 50 ~100 mg/L paclobutrazol. Cultivation of duckweed best control within 6 days. Accumulation of starch content compared with the blank increased by 258%,263%.