在温室内,以原沉积物(CK)和分别添加0.24%与0.48%氯化铵(SN1和SN2)的沉积物作为底质培养沉水植物,研究了穗花狐尾藻对高浓度铵态氮胁迫的生理响应.结果表明:不同处理沉积物、间隙水和上覆水中铵态氮浓度分别在12.35~870.32 mg·kg-1 、1.09~1036.05 mg·L-1和0.10~24.30 mg·L-1,与CK相比,SN1和SN2处理的穗花狐尾藻生物量、株高和根长分别降低了19.69%和81.16%、15.66%和55.52%与45.72%和67.65%.不同处理根系和叶片SOD活性均表现为SN1<SN2<CK;叶片过氧化物酶(POD)和过氧化氢酶(CAT)活性均表现为SN2<SN1<CK,但SN1和SN2根系POD和CAT活性则显著高于CK;SN1、SN2叶片和根系丙二醛(MDA)含量分别比CK提高了46.30%、82.75%和19.66%、55.19%.不同浓度铵态氮对穗花狐尾藻均具有毒害作用,而且铵态氮浓度越高,植物生理响应越明显.
With the sediment applied with 0, 024%, and 048% NH4Cl (treatme
nts CK, SN1, and SN2) as the substrate, a greenhouse experiment was conducte
d to study the physiological responses of Myriophyllum spicatum to ammonium nitr
ogen. The NH4+-N concentration in the sediment, pore-water, and overlying
-water ranged in 1235〖KG-*2〗-〖KG-*7〗87032 mg·kg-1, 109〖KG-*2
〗-〖KG-*7〗103605 mg·L-1, and 010〖KG-*2〗-〖KG-*7〗2430 mg·L-1
, respectively. Comparing with those in CK, the plant height, root length, and
fresh biomass of M. spicatum in treatments SN1 and SN2 decreased by 15
66% and 5552%, 4572% and 6765%, and 1969% and 8116%, respectively. T
he SOD activity in M. spicatum leaves and roots was SN1<SN2<CK, but the
peroxidase (POD) and catalase (CAT) activities in the leaves were SN2<SN1<CK, while those in the roots were significant higher in SN1 and SN2 than in CK.
The malondialdehyde (MDA) contents of leaves and roots in SN1 and SN2 were
increased by 4630% and 8275%, and 1966% and 5519%, respectively. It was
suggested that NH4+-N had toxic effects on M. spicatum, and the higher
the NH4+-N concentration in sediment, the more obvious the physiological re
sponses of M. spicatum exhibited.