Abstract: Effects of soil saline type on the root spatial distribution pattern and growth characteristics of switchgrass (Panicum virgatum L.) were studied using soil column method to define the response mechanism of switchgrass on different salt stress (NaCl 0.40%,Na₂SO₄ 0.80% and NaHCO₃ 0.80%) and to provide a theoretical basis of cultivation management.Results showed that the size of tope third leaf,leaf chlorophyll-a content,above-and underground root biomass,total biomass,seed yield,and the ratio of root to shoot were significantly decreased under soil salinity treatments,whereas leaf chlorophyll-b and total chlorophyll content increased.Total root length,root surface area,and root volumes were inhibited.Under NaCl treatment,the plant height was not significantly different from that of CK.Roots concentrated growth in 0～40 cm of soil layer with biomass gravity changing to 23 cm from 50 cm (CK) soil layer.Under Na₂SO₄ treatment,root distributed in 0～120 cm of soil layer and gradually decreased along with the increasing of soil depth.Under NaHCO₃ treatment,root concentrated growth in 0～80 cm of soil layer with biomass gravity in 18 cm of soil layer.There were significant influences on root extending of switchgrass in NaCl and NaHCO₃ treatment,but small influences in Na₂SO₄ treatment.

Key words: Switchgrass, Saline type, Root vertical distribution

摘要： 采用土柱法研究了土壤NaCl(0.40%)、Na₂SO₄(0.80%)和NaHCO₃(0.80%)胁迫对建植当年柳枝稷(Pani-cum virgatum L.)根系垂直分布和植株生长的影响,以期明确不同盐分胁迫下柳枝稷的响应机制,为其在盐渍土地上的栽培管理提供理论依据。结果表明:盐土条件下,柳枝稷的倒三叶尺寸、叶绿素a含量、地上和地下生物量、总生物量、籽粒产量和根冠比均显著低于对照(无盐处理),叶绿素b和总叶绿素含量增加,对总根长、根表面积和根体积的抑制作用显著。土壤盐分类型为NaCl时,柳枝稷的株高与CK差异不显著,根系生物量重心上移至23 cm(CK为50 cm),根系集中分布在0～40 cm土层;土壤盐分类型为Na₂SO₄时,根系生物量重心上移至38 cm,根系分布在0～120 cm土层范围内,且随着土层深度的增加而逐渐减少;土壤盐分类型为NaHCO₃时,根系生物量重心上移至18 cm,根系集中分布在0～80 cm土层。NaCl和NaHCO₃对柳枝稷根系向下延伸的影响较大,而Na₂SO₄对根系向下延伸的影响较小。

关键词: 柳枝稷, 盐分类型, 根系垂直分布