为探究腐殖酸与生物质炭配施化学磷肥对酸性土壤磷素活化及甘蔗生长的影响.采用盆栽试验,探究了2个施磷水平和2种磷素活化剂的施用对土壤养分、磷素转化及甘蔗生长的影响.结果表明,腐殖酸与生物质炭单独施用或配合施用提高了土壤速效磷、磷素活化率、有机质、有效钾、碱解氮的含量及磷酸酶的活性,且甘蔗株高、茎粗、全磷含量、磷积累量及磷肥利用率也有所提高,但显著降低了土壤无机磷O-P的含量,其中0.1 g/kg磷肥+2 g/kg腐殖酸处理(P1F)的土壤O-P含量显著低于单施0.1 g/kg磷肥处理(P1)49.35％,腐殖酸与生物质炭配施处理(P1FS)较空白对照处理(CK)的土壤有机质含量和磷酸酶活性分别显著提高了29.31％和42.11％.在2个施磷水平下,腐殖酸与生物质炭的施用对土壤无机磷形态含量增加的效果从大到小依次为Fe-P>Ca-P>Al-P>O-P.表明施用腐殖酸与生物质炭提高了土壤的速效养分、磷素含量、磷酸酶活性,促进了土壤磷素转化,进而影响了甘蔗对磷素的吸收利用.

[目的]探究镉(CdCl2)胁迫下甘蔗幼苗根系细胞壁Cd的积累特点及Cd对甘蔗种茎初生根的影响,为在土壤Cd超标区域推广种植甘蔗新品种提供参考依据.[方法]以新选育的中蔗1号(Z1)和中蔗6号(Z6)为试验材料,开展不同浓度(1.0、2.0和5.0 μmol/L) CdCl2胁迫水培试验,测定甘蔗幼苗根系的Cd含量和细胞壁中的Cd积累量、果胶和半纤维素含量及甘蔗种茎初生根的相对伸长率和根尖活力等指标,分析根系细胞壁在缓解Cd毒害中的作用并评价2个甘蔗新品种的Cd耐受性.[结果]1.0、2.0和5.0 μmol/L CdCl2处理Z1和Z6幼苗根系的Cd含量分别约为其叶片Cd含量的136、124和116倍;甘蔗根系对Cd具有较强的截留能力,其中5.0 μmol/L CdCl2处理甘蔗幼苗根系中的Cd有57.50％位于根系细胞壁中,而细胞壁中的Cd有95.00％以上积累在果胶和半纤维素组分中,且随着CdCl2胁迫浓度(1.0、2.0和5.Oμmol/L)的提高积累在果胶组分中Cd的比例(18.71％、28.52％和36.28％)显著增加(P ＜0.05,下同).同时,甘蔗幼苗根系细胞壁的果胶含量、果胶甲酯酶(PME)活性和去甲酯化果胶含量也随着CdCl2胁迫浓度的提高而增加,使得更多的Cd被细胞壁果胶所吸附固定.CdCl2胁迫下Z1根系和叶片的Cd含量显著高于Z6,而根系相对伸长率和根尖活力与Z6相近,表明Z1对Cd的耐受性强于Z6.[结论]在CdCl2胁迫下,甘蔗幼苗根系的细胞壁是Cd积累的主要部位;CdCl2胁迫致使甘蔗根系细胞壁果胶组分含量增加,PME活性提高,果胶甲酯化程度降低,细胞壁对Cd的结合能力提高,使得更多的Cd被根系细胞壁所吸附积累.

In this study,120 different sugarcane varieties from different regions or having different genetic backgrounds were used to study the phosphorus (P) genetic differences and screen high and low P efficiency in fields.The main results are as follows:Low P stress had a significant impact on shoot biomass,plant height,P accumulation,P utilization efficiency and P content in leaves (+5) at seedling stage.Shoot biomass was significantly correlated with P accumulation,P utilization efficiency,but showed no significant correlation with other traits.Cluster analysis of shoot biomass,P accumulation and P utilization efficiency at seedling stage of sugarcane showed that the tested varieties could be divided into 5 types,namely low-yield and low P efficiency,relatively low-yield and relatively low P efficiency,high-yield and low P efficiency,low-yield and high P efficiency,high-yielding and high P efficiency.Based on the P efficiency associated traits at seedling stage and cane yield at mature stage,five sugarcane genotypes of high P efficiency,that is,FN91-21,MT01-77,GT97-69,YR06-8270 and YR06-8362,and five sugarcane genotypes of low phosphorus efficiency,that is,Co285,TY14,YR05-782,YR05-784 and YR06-2414 were selected.The above results would provide an important basis for breeding P efficient cultivars and deeply studying P efficient mechanism.