The Effects Of Silicon On The Growth And Drought Resistance Of Turfgrass Under Drought Stress

In order to study the effects of silicon on growth and physiological characteristic of turfgrass under drought stress, Bermurd, Kentucky bluegrass, and Tall fescue were used as experimental material,and irrigated by three irrigation treatments (irrigating according to 100%, 75%, and 50% of maximum field capacity ) 45 d at the first stage, and at the same time 0, 28ppm, 56ppm, 112ppm silicon acid were applied. Evapotranspiration (ET), leave relative water content (RWC), leave relative electrothye leakage (EL), turf quality (TQ), superoxidation (SOD) activity, catalase (CAT) activity, malondialdehyde (MDA) content, root dry weight (RDW), and root activity (RACT) were determined during the experiment. At the second stage, all tested cultivars were rewatered fully 50 d, and meanwhile 0, 28ppm, 56ppm, 112ppm silicon acid were applied, following rewatering, the third stage drought stress treatment began, Tall fescue could recover best, and then was made as trial material to expose drought stress 30 d, during drought stress RWC, EL, LW, TQ, SOD, CAT, and MDA were determined. Main conclusions as following:1. Under three irrigation conditions, ET of three tested turfgrasses showed decreasing trend with decreasing irrigation content. Following different concentration silicon fertilizer were applied, ET of three tested turfgrasses for FWC100 treatment did not change markedly, while ET of three tested turfgrasses for FWC75 and FWC50 declined with increasing silicon fertilizer concentration, especially, ET of three tested turfgrasses for FWC50 declined markedly.2. RWC of three tested turfgrasses for FWC75 and FWC50 decreased more markedly than that of three tested turfgrasses for FWC100, RWC of three tested turfgrasses for FWC50 declined most markedly. Following different concentration silicon fertilizer were applied, RWC of three tested turfgrasses for FWC100 hardly kept the same level, RWC of three tested turfgrasses for FWC75 and FWC50 increased markedly with increasing silicon fertilizer concentration, especially RWC of three tested turfgrasses for FWC50 increased most markedly. Silicon fertilizer can enhance drought resistance of tested turfgrasses.3. At un-silicon fertilizer treatment, EL of three tested turfgrasses for FWC75 and FWC50 was higher than that of three tested turfgrasses for FWC100, especially EL of three tested turfgrasses for FWC50 increased most markedly. Following different concentration silicon fertilizer were applied, EL of three tested turfgrasses for FWC100 treatment did not change markedly with increasing silicon fertilizer concentration, while EL of three tested turfgrasses for FWC75 and FWC50 decreased markedly, especically EL of three tested turfgrasses for FWC50 declined most markedly, and EL of three tested turfgrasses for FWC50 and FWC75 decreased obviously under Si56 treatment. Silicon fertilizer can enhance drought resistance of tested turfgrasses.4. At un-silicon fertilizer treatment, TQ of three tested turfgrasses for FWC75 and FWC50 decreased more markedly than that of three tested turfgrasses for FWC100, less irrigation water, lower TQ. Following different concentration silicon fertilizer were applied, TQ of three tested turfgrasses for FWC100 treatment did not change markedly with increasing silicon fertilizer concentration, silicon could not improve TQ. While TQ of three tested turfgrasses for FWC75 and FWC50 increased markedly with increasing silicon fertilizer concentration, TQ of three tested turfgrasses increased most markedly under Si56 treatment. Silicon fertilizer can enhance drought resistance of tested turfgrasses.5. At un-silicon fertilizer treatment, SOD and CAT activity of three tested turfgrasses for FWC75 and FWC50 were much lower than that of three tested turfgrasses for FWC100, less irrigation water, lower SOD and CAT activity. Following different concentration silicon fertilizer were applied, SOD and CAT activity of three tested turfgrasses for FWC100 did not increase markedly with increasing silicon fertilizer concentration, while SOD and CAT activity of three tested turfgrasses for FWC75 and FWC50 increased obviously with increasing silicon fertilizer concentration, whatever, silicon fertilizer could improve SOD and CAT activity of three tested turfgrasses under less irrigation water condition, especially, SOD and CAT activity of three tested turfgrasses increased markedly under Si56 treatment. Silicon fertilizer can enhance drought resistance of tested turfgrasses.6. At un-silicon fertilizer treatment, MDA content of three tested turfgrasses for FWC75 and FWC50 were much higher than that of three tested turfgrasses for FWC100, especially MDA content of three tested turfgrasses for FWC50 increased most obviously. Following different concentration silicon fertilizer were applied, MDA content of three tested turfgrasses for FWC100 did not increase obviously with increasing silicon fertilizer concentration, while MDA content of three tested turfgrasses for FWC75 and FWC50 decreased markedly with increasing silicon fertilizer concentration, especically MDA content of three tested turfgrasses declined markedly under Si56 treatment. Silicon fertilizer can enhance drought resistance of tested turfgrasses.7. At un-silicon fertilizer treatment, RDW and RACT of three tested turfgrasses for FWC75 and FWC50 were much lower than that of three tested turfgrasses for FWC100, less irrigation water, lower RDW and RACT of three tested turfgrasses. Following different concentration silicon fertilizer were applied, RDW and RACT of three tested turfgrasses for FWC100 did not change obviously with increasing silicon fertilizer concentration, and kept the same level, while RDW and RACT of three tested turfgrasses for FWC75 and FWC50 increased markedly with increasing silicon fertilizer concentration, especically RDW and RACT of three tested turfgrasses increased most markedly under Si56 treatment. Silicon fertilizer can enhance drought resistance of tested turfgrasses.8. RWC and TQ of tested Tall fescue declined obviously under drought stress following rewatering treatment, RWC and TQ of tested Tall fescue without application of silicon fertilizer was lower than that of tested Tall fescue with application of silicon fertilizer. Under drought stress, RWC and TQ of tested Tall fescue gradually declined with increasing silicon fertilizer concentration,RWC and TQ of tested Tall fescue with application of silicon fertilizer was higher than that of tested Tall fescue without application of silicon fertilizer,whatever, RWC and TQ of tested Tall fescue for FWC100 was lower than that for FWC75 and FWC50 at the same silicon fertilizer concentration. Drought exercise and silicon fertilizer can enhance drought resistance of tested Tall fescue.9. EL and LW of tested Tall fescue increased obviously under drought stress following rewatering treatment. At the end of drought stress (30 d), EL and LW of tested Tall fescue without application silicon fertilizer was much higher than that of tested Tall fescue with application silicon fertilizer; whatever, EL and LW of tested Tall fescue for FWC50 was lower than that of tested Tall fescue for FWC100 and FWC75 at the same silicon fertilizer concentration. Drought exercise and silicon fertilizer can enhance drought resistance of tested Tall fescue.10. SOD of tested Tall fescue increased momently and then decreased obviously, while CAT activity declined continuously under drought stress following rewatering treatment. At the end of drought stress (30 d), SOD and CAT activity of tested Tall fescue without application silicon fertilizer was much lower than that of tested Tall fescue with application silicon fertilizer; SOD and CAT activity of tested Tall fescue under drought stress were relative high with increasing silicon fertilizer concentration, whatever, SOD and CAT activity of tested Tall fescue for FWC50 were higher than that of tested Tall fescue for FWC100 and FWC75 at the same silicon fertilizer concentration. Drought exercise and silicon fertilizer can enhance drought resistance of tested Tall fescue.11. MDA content of tested Tall fescue increased obviously under drought stress following rewatering treatment. At the end of drought stress (30 d), MDA content of tested Tall fescue without application silicon fertilizer was much higher than that of tested Tall fescue with application silicon fertilizer; MDA content of tested Tall fescue declined differently with increasing silicon fertilizer concentration, whatever, MDA content of tested Tall fescue for FWC50 was lower than that of tested Tall fescue for FWC75 and FWC100, At the end of drought stress (30 d), MDA content of tested Tall fescue for Si56 was relative low. Drought exercise and silicon fertilizer can enhance drought resistance of tested Tall fescue.