不同基质配比对醉香含笑苗期生长和根系形态的影响OA

To promote the resource-recycling of garden waste and screen suitable growing substrates for Michelia macclurei seed-lings,a single-factor randomized block experiment was adopted with M.macclurei seedlings as experimental materials.Six types of substrates were prepared mainly using garden waste.This study aimed to determine physicochemical properties of different substrates and their influences on seedling growth,leaf SPAD values(relative chlorophyll content),and root morphology of M.macclurei.Principal component analysis(PCA)was applied to comprehensively evaluate seedling-rai-sing performance of various substrates.The results showed that pH and electrical conductivity(EC)values of garden-waste-only substrate were significantly higher than those of other substrates,its nutrient contents were at a moderate level while total porosity was relatively low.However,the addition of peat,coconut husk fibre,and perlite could significantly improve substrate permeability and enhance nutrient content.Peat-soil-based formulations significantly increased seedling height,ground diameter and biomass accumulation of M.macclurei,whereas they imposed limited effects on leaf SPAD values.Meanwhile,these substrates exerted pronounced influences on root morphology.Root length,root surface area,root volume,specific root length and specific root surface area greatly increased after peat-soil addition,while root tissue density decreased correspondingly.Correlation analysis revealed that substrate physicochemical properties were closely as-sociated with seedling development.Organic-matter content,available phosphorus content and total porosity exhibited strong positive correlations with most growth-and root-morphology indices of M.macclurei.Comprehensive evaluation based on principal-component analysis ranked the seedling-raising effectiveness from high to low as follows:peat-soil-based mixtures,yellow-soil-based mixtures,and pure garden-waste substrate.Furthermore,M.macclurei could adapt to varied substrate environments by adjusting root traits and switch between an acquisitive and conservative root strategy,showing high root phenotypic plasticity and environmental adaptability.Garden waste can serve as a replacement for peat soil and yellow subsoil as the principal component of growing media,yet supplements such as peat soil and coconut husk are re-quired to optimize substrate porosity and nutrient conditions.Comprehensive analysis of seedling-growth and root-morpholo-gy indices indicated that the mixtures with volume ratios of garden waste∶peat soil∶perlite∶vermiculite=6∶2∶1∶1(V/V)and garden waste∶peat soil∶coir=6∶3∶1(V/V)achieved superior seedling-raising outcomes and could be rec-ommended as ideal substrates for M.macclurei seedling cultivation.