铜、镉、铅对高羊茅种子萌发及幼苗生长的影响

Effects of copper,cadmium and lead on seedgermination and seedling growth of tall fescue

摘要:

以高羊茅火凤凰2号(Phoenix Ⅱ)为试验材料,研究铜(Cu)、镉(Cd)、铅(Pb)对高羊茅(Festuca arundinacea)种子萌发和幼苗生长的影响。分别用CuSO₄· 5H₂O,3CdSO₄·8H₂O和Pb(NO₃)2溶液模拟重金属胁迫处理高羊茅种子,设置低浓度、中浓度、较高浓度、高浓度4个浓度梯度,分别为Cu²⁺(200、300、400、500 mg/L);Cd²⁺(1、50、100、150 mg/L);Pb²⁺(500、1 000、1 500、2 000 mg/L)。通过测定火凤凰2号的相对发芽率、相对发芽势、发芽指数、活力指数、叶表面积、根冠比等13个生长指标,研究高羊茅在3种重金属胁迫下的发芽及幼苗生长状况。结果表明:高羊茅对镉胁迫的耐受性最好,中、低浓度铜胁迫下幼苗耐受性较差,较高浓度及高浓度下对铅胁迫的耐受性最差。铜胁迫下随着胁迫程度的加剧,各项指标均呈下降趋势且幼苗生长受到抑制;低浓度镉、铅胁迫对种子萌发及幼苗生长有促进作用,随着胁迫程度的增高,种子萌发和幼苗生长会受到明显的抑制。当Pb²⁺≥1 500 mg/L时,高羊茅幼苗根系生长受到完全抑制,生长量为0,出现“无根苗”。

Abstract:

The effects of simulated Copper (Cu),Cadmium (Cd) and Lead (Pb) iron stresses on seed germination and seedling growth of Tall festuca (Festuca arundinacea) were studied by using the cultivar of Phoenix Ⅱ as tested material.CuSO₄·5H₂O,3CdSO₄·8H₂O,and Pb(NO₃)₂ solutions were used to moisten germination bed to simulate heavy metals on tall fescue seeds′ germination,and four concentration gradients were established: lower,medium,higher,and heavy concentration,respectively,which were as follow:Cu²⁺ (200,300,400 and 500 mg/L);Cd²⁺ (1,50,100 and 150 mg/L);Pb2⁺ (500,1 000,1 500 and 2 000 mg/L).The germination dynamic and growth status of tall fescue under above-mentioned three heavy metals were surveyed by measuring 13 germination and seedling growth related indices including relative germination potential,relative germination rate,germination index,vigor index,leaf surface area and ratio of root to shoot in Phoenix II.The results showed that the tall fescue had the better resistance to cadmium,poor resistance to copper under lower and medium stresses,and the resistance to lead was the least under higher and heavy stresses.All the observed indices appeared decreasing and the growth potential was inhibited with the stress of copper stress increasing.Seed germination and seedling growth were promoted under lower concentration stresses of cadmium and lead.With the increasing of stress concentration,seed germination and seedling growth were considerably inhibited,seedling growth especially the root growth of tall fescue was completely inhibited When Pb²⁺ higher than 1 500 mg/L,there was no root present from embryo,and ‘rootless seedling’ appeared.