小麦秸秆复合基质的理化指标及其对黄瓜幼苗生长和光合参数的影响

Physicochemical indexes of mixed substrates of wheat(Triticum aestivum) straw and its effect on growth and photosynthetic parameters of Cucumis sativus seedling

以小麦(Triticum aestivum L.)秸秆基质(发酵)为主,按不同比例分别添加蛭石、珍珠岩和草炭,配制10种复合基质;以不含小麦秸秆基质的复合基质为对照,对各基质的基本理化性状进行了分析和比较,并研究了不同基质对黄瓜(Cucumis sativus L.)幼苗生长、叶片叶绿素含量和光合参数的影响。结果显示:不同基质的理化指标有明显差异,小麦秸秆基质与蛭石、珍珠岩和草炭混配均降低或显著降低了基质的容重、总孔隙度、持水孔隙度、水气比、小颗粒含量、pH值和电导率,提高了通气孔隙度以及大、中颗粒的含量。按V(小麦秸秆基质)∶V(蛭石)∶V(草炭)=50∶25∶25的比例配制的复合基质T9的容重、总孔隙度、通气孔隙度、持水孔隙度、水气比和电导率分别为0.33g.cm-3、68.1%、15.3%、52.8%、3.45和3.91 mS.cm-1,理化性状最佳,具有良好的吸水和保水性能。总体上看,随复合基质中小麦秸秆基质比例的降低,黄瓜幼苗的株高、茎粗、根总长、根总体积、平均单根直径和根尖总数、生物量和壮苗指数以及叶片的叶绿素含量均呈上升趋势;复合基质中小麦秸秆基质比例较高,黄瓜叶片的净光合速率、气孔导度和蒸腾速率均较低,但与对照相比,不同基质对叶片胞间CO2浓度及水分利用效率无显著影响。在复合基质T9中黄瓜幼苗的这些生长指标、壮苗指数以及叶片叶绿素含量和光合参数总体上高于或显著高于对照和其他复合基质,生长良好。结果表明:复合基质T9较适合黄瓜幼苗的生长发育,可作为黄瓜育苗基质。

Taking the wheat（Triticum aestivum L.） straw substrate（fermented） as main material,ten mixed substrates were prepared by adding vermiculite,perlite and peat with different ratios.And taking the mixed substrate without wheat straw substrate as the control,the basic physicochemical properties of different substrates were analyzed and compared,and their effects on growth,chlorophyll content and photosynthetic parameters of leaf of Cucumis sativus L.seedling were investigated.The results show that difference of physicochemical indexes among different substrates is obvious.When wheat straw substrate is mixed with vermiculite,perlite and peat,its bulk density,total porosity,water-holding porosity,ratio of water to air,small granule content,pH value and electrical conductivity all are decreased or significantly decreased,but aeration porosity and contents of large and medium granules are increased.While the T9 mixed substrate,which is prepared according to the ratio of V（wheat straw substrate） ∶V（vermiculite） ∶ V（peat）=50 ∶ 25 ∶ 25,shows the best physicochemical properties and well water-absorption and water-retention properties,and its bulk density,total porosity,aeration porosity,water-holding porosity,ratio of water to air and electrical conductivity are 0.33 g·cm-3,68.1%,15.3%,52.8%, 3.45 and 3.91 mS·cm-1,respectively.Generally,the height,stem diameter,total length of root,total volume of root,average diameter of single root,total number of root tip,biomass,strength index and leaf chlorophyll content of C.sativus seedling appear the increasing trend with decreasing of the ratio of wheat straw substrate in mixed substrate.When the ratio of wheat straw substrate in mixed substrate is higher,net photosynthetic rate,stomatal conductance and transpiration rate of leaf all are lower.But comparing with the control,effect of different substrates on intercellular CO2 concentration and water use efficiency of leaf is not significant.These growth indexes,strength index and chlorophyll content and photosynthetic parameters of leaf of C.sativus seedling in T9 mixed substrate generally are higher or significantly higher than those in the control and other mixed substrates,and the seedling grows better.It is concluded that T9 mixed substrate is suitable for growth and development of C.sativus seedling,and can be used for its breeding cultivation.