葎草幼苗对盐胁迫响应的性别差异

采用盆栽试验研究了葎草(Humulus scandens)幼苗对盐胁迫响应的生理生化性别差异,测定了不同盐(NaCl)浓度(0、100、200、300mmol·L~(-1))下雌雄植株的单叶面积、气体交换参数、叶水势、叶绿素荧光、叶绿素含量、过氧化氢酶(CAT)和丙二醛(MDA)含量等指标的变化。结果表明,NaCl胁迫后葎草雌雄幼苗的叶干重、净光合速率(P_n)、气孔导度(G_s)、胞间CO_2浓度(C_i)、蒸腾速率(T_r)、叶水势(ψ_w)和CAT均呈逐渐降低的趋势,而气孔限制值(L_s)和MDA逐渐上升,其单叶面积则先升后降。随着NaCl胁迫的递增,雌株的最小荧光(F_o)呈先升后降的变化,最大荧光(_Fm)、可变荧光(F_v)、PSⅡ潜在活性(F_v/F_o)和非光化学淬灭系数(qN)则逐渐递增,光化学淬灭系数(qP)和叶绿素含量却逐渐递减;从总体上看,雄株的表现光合电子传递速率(ETR)、Fm和Fv、最大光化学效率(F_v/F_m)和F_v/F_o也呈上升趋势,qN和qP却呈下降趋势,而叶绿素含量却先升后降。因此,NaCl胁迫影响了葎草雌雄幼苗的单叶面积、叶绿素含量、叶绿素荧光、气体交换、CAT和MDA含量等生理生化特征,但雌雄幼苗对NaCl胁迫的响应存在差异。与雄株相比,雌株对NaCl胁迫更耐受。

Gender differences of Humulus scandens seedlings in response to NaCl stress

In this study, we examined sex-specific differences in leaf area, gas exchange parameters, leaf water potential and chlorophyll fluorescence of male and female seedlings of Humulus scandens under NaCl stress (0, 100, 200 and 300 mmol·L-1 NaCl).Under the effects of NaCl, the net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr), leaf water potential (ψw), catalase (CAT), limiting value of stomata(Ls) and malondialdehyde (MDA) of male and female seedlings increased gradually.The leaf area of single leaves increased first and then decreased.The maximum fluorescence (Fm), the variable fluorescence (Fv), the potential activity of PSⅡ (Fv/Fo) and the non-photochemical quenching coefficient (qN) of the females gradually increased with the increase of NaCl stress.The photochemical quenching coefficient (qP) and chlorophyll content decreased by degrees.Overall, the ETR, Fv, Fv/Fm and Fv/Fo of the males showed an increasing trend, but qN and qP decreased, while chlorophyll content increased first and then decreased.Therefore, the physiological and biochemical characteristics such as single leaf area, chlorophyll content, chlorophyll fluorescence, gas exchange, and CAT and MDA contents in male and female seedlings of H.scandens were affected by NaCl stress.There were significant gender differences in the response of male and female seedlings to NaCl stress.Compared to the males, the females had greater resistance against NaCl stress.