外源Ni对小麦孕穗期生长发育和成熟期产量的影响及其Ni毒害临界值

为探明小麦孕穗期毒害效应与成熟期籽实产量间的关系,实现中期毒害效应诊断与评价,以春小麦"冀张春3号"为材料,采用盆栽试验方法,研究了外源Ni对小麦孕穗期植株生长和成熟期籽实产量的影响,并对不同生育期的生理指标进行了相关分析.结果表明,外源Ni会增加小麦孕穗期株高和叶片干质量,减少茎秆和穗干质量,降低成熟期籽实产量,投加Ni量≥100 mg·kg~(-1)时出现明显抑制作用,茎秆、穗干质量和籽实产量均明显下降(p0.05);小麦孕穗期各器官中Ni含量和富集系数由大到小的顺序为:根系穗茎秆叶片,外源Ni会明显增加小麦孕穗期各器官和籽实中Ni含量,其中,小麦穗和籽实中Ni含量和富集系数随Ni投加量的增加均呈二次吸收富集高峰.相关分析结果表明,土壤中各形态Ni含量与小麦孕穗期各器官和籽实中Ni含量均呈显著正相关(p0.05,p0.01),根系和穗中Ni及土壤不同形态Ni含量与茎秆、穗干质量和籽实产量呈显著负相关(p0.05,p0.01),茎秆和穗干质量与籽实产量均呈显著正相关(p0.05).研究提出,利用小麦孕穗期毒害效应突变点指标表征小麦外源Ni毒害临界值是可行的,其毒害临界值指标为:土壤全Ni含量为139.08 mg·kg~(-1),土壤有效态Ni(DTPA提取)含量为21.59 mg·kg~(-1),小麦穗Ni含量为19.17 mg·kg~(-1),小麦根系Ni含量为318.49 mg·kg~(-1).

Effects of exogenous Ni on development at booting stage and yield at maturity stage in wheat (Triticum aestivum L.) and exploration of Ni toxic critical value

The objective of the study was to explore the relationship between the toxic effects at booting stage and yield at maturity stage in spring wheat and to further evaluate the medium-term toxicity in wheat growth process. The spring wheat variety Jizhangchun-3 was used as the materials by pot experiment to verify the effects of exogenous Ni on the wheat development at booting stage and yield at maturity stage. The correlation of the physiological indexes at both stages was also studied. The results showed that both plant height and leaf dry weight increased but the stem-and ear-dry weight decreased at booting stage while the yield decreased at maturity stage. If the usage of exogenous Ni exceeded 100 mg·kg^-1, the stem-and ear-dry weight as well as the yield decreased significantly. Ni contents and the enrichment coefficients in the different organs at booting stage ranged from root, ear, stem to leaf. Exogenous Ni might contribute to Ni accumulation in almost all organs at booting stage and mainly in grain at maturity stage, and absorption curves displayed double peaks. The correlation between Ni contents in soil and Ni contents in wheat organs at booting stage as well as in grain at maturity stage appeared significantly positive. Ni contents in root, in ear and in soil were negatively correlated with stem-and ear-dry weight and yield in grain. However, the stem-and ear-dry weight was positively correlated with the yield in grain. The toxicity indexes at booting stage could be feasible to characterize exogenous Ni toxicity critical value, which would be 139.08 mg·kg^-1 total Ni in soil, 21.59 mg·kg^-1 available Ni in soil (DTPA extraction), 19.17 mg·kg^-1 Ni in ear or 318.49 mg·kg^-1 Ni in root, respectively.