【目的】探究白柳(Salix alba L.)在碱胁迫下根系及光合特性的调控机制.【方法】以树龄1 a白柳插条为试材,通过水培的方式模拟在不同pH的碱处理(mNa_(2)CO_(3)∶mNaHCO_(3)=1∶1)下,持续处理20 d后白柳根系的生长状况、光合作用及叶绿...【目的】探究白柳(Salix alba L.)在碱胁迫下根系及光合特性的调控机制.【方法】以树龄1 a白柳插条为试材,通过水培的方式模拟在不同pH的碱处理(mNa_(2)CO_(3)∶mNaHCO_(3)=1∶1)下,持续处理20 d后白柳根系的生长状况、光合作用及叶绿素荧光对碱胁迫的响应.【结果】随碱胁迫加剧,白柳的平均根数、平均根长和生根指数显著降低,受害症状表现明显;叶片净光合速率(P_(n))、蒸腾速率(E)、气孔导度(G_(s))总体呈逐渐下降趋势;胞间CO_(2)浓度(C_(i))呈先降后升的趋势,其中溶液pH<8.5时,叶片P_(n)下降主要受气孔因素限制,当pH>8.5时,P_(n)下降主要由非气孔因素限制,且E的下降幅度明显大于Pn;碱胁迫下白柳快速叶绿素荧光诱导动力学曲线(OJIP曲线)变为OKJIP曲线,溶液pH>8.0时,I、P点荧光值显著下降且出现明显拐点K;光系统II(PSII)反应中心量子产额和能量分配比率明显变化(φPo、Ψo和φEo受到抑制,φDo得到促进);性能指数及推动力(PI_(ABS)、PI_(CSm)和DF_(CSm))呈明显下降趋势,说明碱胁迫使PSII反应中心部分失活、供体侧与受体侧功能受到损害.【结论】白柳可通过调节P_(n)与E的下降幅度在一定程度上确保自身对蒸腾耗水的利用能力,以提高φDo等方式来应对碱胁迫,表现出一定的自我调节适应能力.展开更多
We used a salt-resistant poplar genotype Populus euphratica and two salt-sensitive genotypes, Populus 'popularis 35-44' (P. popularis) and the hybrid P. talassica Kom x (P. euphratica + Salix alba L.) to exami...We used a salt-resistant poplar genotype Populus euphratica and two salt-sensitive genotypes, Populus 'popularis 35-44' (P. popularis) and the hybrid P. talassica Kom x (P. euphratica + Salix alba L.) to examine genotypic differences in nutrient selectivity under NaCl stress. One-year-old seedlings of P. euphratica and one-year-old hardwood cuttings of P. popularis were used in a short-term study (24 hours), while in a long-term study, up to 4 weeks, two-year-old seedlings of P. euphratica and the hybrid P. talassica Kom x (P. euphratica + Salix alba L.) were compared. In the short-term study, K+ concentration in the xylem sap ([K+]xylem) of P. euphratica significantly increased after salt stress was initiated, and maintained 1-2 fold higher than control levels during the period of salt stress (24 hours). Xylem Ca2+ and Mg2+ concentrations ([Ca2+]xylem, [Mg2+]xylem) in P. euphratica resembled the pattern of K+ despite a lesser magnitude in elevation. However, [K+]xylem, [Ca2+]xylem and [Mg2+]xylem in P. popularis exhibited a transient increase at the beginning of salt treatment, thereafter, they all returned to control levels at 4 hours and no further rise was observed in the following hours. Xylem Na+/K+, Na+/Ca2+ and Na+/Mg2+ in P. popularis increased sharply upon NaCl stress and steadily reached the maximum at 24 hours. In contrast, xylem Na+/K+, Na+/Ca2+ and Na+/Mg2+ in NaCl-treated plants of P. euphratica did not significantly increase during the period of salt stress (24 hours). Noteworthy, Na+/K+ markedly declined after the onset of stress. These results suggest that P. euphratica had a higher nutrient selectivity in face of salinity. A same trend was observed in a 4-week study. Xylem Na+/K+, Na+/Ca2+ and Na+/Mg2+ in salinised plants of the hybrid abruptly increased after 4 days of stress, and then continuously increased to reach the highest level at day 8 or day 15. In comparison, the magnitude of Na+/K+, Na+/Ca2+ and Na+/Mg2+ elevation in the xylem of P. euphratica was much lower during the observation p展开更多
文摘【目的】探究白柳(Salix alba L.)在碱胁迫下根系及光合特性的调控机制.【方法】以树龄1 a白柳插条为试材,通过水培的方式模拟在不同pH的碱处理(mNa_(2)CO_(3)∶mNaHCO_(3)=1∶1)下,持续处理20 d后白柳根系的生长状况、光合作用及叶绿素荧光对碱胁迫的响应.【结果】随碱胁迫加剧,白柳的平均根数、平均根长和生根指数显著降低,受害症状表现明显;叶片净光合速率(P_(n))、蒸腾速率(E)、气孔导度(G_(s))总体呈逐渐下降趋势;胞间CO_(2)浓度(C_(i))呈先降后升的趋势,其中溶液pH<8.5时,叶片P_(n)下降主要受气孔因素限制,当pH>8.5时,P_(n)下降主要由非气孔因素限制,且E的下降幅度明显大于Pn;碱胁迫下白柳快速叶绿素荧光诱导动力学曲线(OJIP曲线)变为OKJIP曲线,溶液pH>8.0时,I、P点荧光值显著下降且出现明显拐点K;光系统II(PSII)反应中心量子产额和能量分配比率明显变化(φPo、Ψo和φEo受到抑制,φDo得到促进);性能指数及推动力(PI_(ABS)、PI_(CSm)和DF_(CSm))呈明显下降趋势,说明碱胁迫使PSII反应中心部分失活、供体侧与受体侧功能受到损害.【结论】白柳可通过调节P_(n)与E的下降幅度在一定程度上确保自身对蒸腾耗水的利用能力,以提高φDo等方式来应对碱胁迫,表现出一定的自我调节适应能力.
基金Foundation for the Author of National Excellent Doctoral Dissertation of PRC (Grant No. 200152)the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institution of MOE, PRC, the National Nat
文摘We used a salt-resistant poplar genotype Populus euphratica and two salt-sensitive genotypes, Populus 'popularis 35-44' (P. popularis) and the hybrid P. talassica Kom x (P. euphratica + Salix alba L.) to examine genotypic differences in nutrient selectivity under NaCl stress. One-year-old seedlings of P. euphratica and one-year-old hardwood cuttings of P. popularis were used in a short-term study (24 hours), while in a long-term study, up to 4 weeks, two-year-old seedlings of P. euphratica and the hybrid P. talassica Kom x (P. euphratica + Salix alba L.) were compared. In the short-term study, K+ concentration in the xylem sap ([K+]xylem) of P. euphratica significantly increased after salt stress was initiated, and maintained 1-2 fold higher than control levels during the period of salt stress (24 hours). Xylem Ca2+ and Mg2+ concentrations ([Ca2+]xylem, [Mg2+]xylem) in P. euphratica resembled the pattern of K+ despite a lesser magnitude in elevation. However, [K+]xylem, [Ca2+]xylem and [Mg2+]xylem in P. popularis exhibited a transient increase at the beginning of salt treatment, thereafter, they all returned to control levels at 4 hours and no further rise was observed in the following hours. Xylem Na+/K+, Na+/Ca2+ and Na+/Mg2+ in P. popularis increased sharply upon NaCl stress and steadily reached the maximum at 24 hours. In contrast, xylem Na+/K+, Na+/Ca2+ and Na+/Mg2+ in NaCl-treated plants of P. euphratica did not significantly increase during the period of salt stress (24 hours). Noteworthy, Na+/K+ markedly declined after the onset of stress. These results suggest that P. euphratica had a higher nutrient selectivity in face of salinity. A same trend was observed in a 4-week study. Xylem Na+/K+, Na+/Ca2+ and Na+/Mg2+ in salinised plants of the hybrid abruptly increased after 4 days of stress, and then continuously increased to reach the highest level at day 8 or day 15. In comparison, the magnitude of Na+/K+, Na+/Ca2+ and Na+/Mg2+ elevation in the xylem of P. euphratica was much lower during the observation p
