The Effects Of Silicon On Growth And Development Of Kentucky Bluegrass Seedlings Under Drought Stress

The objective of this study is to investigate the growth characteristics at seedling stage of Kentucky bluegrass(Poa pratensis L.) under a range of soil water capacity. This growth chamber experiment was consisted of five soil water capacity treatments (70%,60%,50%,40%and30%of filed water capacity (FWC)); The objective of the study was to investigate effects of increasing amendment concentrations of K2Si03on seedling growth of Kentucky bluegrass under well watered conditions. This growth chamber experiment was consisted of a control (no Si) and four Si amendment treatments (1,1.5,2and2.5mmol·L-1); This experiment was consisted of three soil water capacity treatments (55%(sufficient soil water),45%(mild drought stress) and35%(severe drought stress)of filed water capacity), setting three treatments under each soil moisture gradient, namely Si treatment (0.48g/kg SiO2),K treatment (0.62g/kg KC1) and CK (NO K2SiO3and KC1), researched the effects of Silicon on the emergence and drought tolerance of Kentucky bluegrass under drought stress.The main results were:1. The seeding emergence rate of Kentucky bluegrass had significantly positive relationships with soil water capacity and it increased with the increasing of soil water content. The trend of the length and weight of fresh seedlings were FWC60>FWC70>FWC50>FW40C>FWC30, and the root length and fresh weight, total length of roots, average root diameter, total surface areas of roots and number of tips were FWC60>FWC50>FWC70>FW40C>FWC30.In a word, FWC70and FWC30treatment are unfavorable to sustainable development of turfgrass. FWC50to60could be used as an ideal soil water level for Kentucky bluegrass growth.2. Silicon fertilizer can significantly promote germination rate, germination energy and germination index of the seed.The length and fresh weight of seedlings were significantly increased at35d of the experiment with the increasing of silicon fertilizer, and the root length, total surface areas of roots and average root diameter, of Si2.5treatment was significantly higher than the control.3. Silicon can promote the seed germination rate of Kentucky bluegrass under slightly drought stress, silicon did not affect the seed germination rate under sufficient soil water or severe drought stress conditions. Under drought stress, addition of silicon can decrease evapotranspiration, leaf relative conductivities and MDA capacity, and improve leaf relative water capacity.