摘要
以沙棘和银水牛果2年生幼苗为试材,设NaCl浓度分别为0、200、400和600mmol·L-1,研究NaCl胁迫对其生长及光合特性的影响.结果表明:随着NaCl浓度的增加,沙棘和银水牛果幼苗的生物量、单株总叶面积均显著下降,且NaCl浓度越高,下降幅度越大.不同NaCl浓度处理下,沙棘和银水牛果幼苗根冠比较对照显著增加,比叶质量(LMA)略有降低.随着NaCl浓度的增加和胁迫时间的延长,沙棘和银水牛果叶片净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)均明显下降,胞间CO2浓度(Ci)先降后升,气孔限制值(Ls)和水分利用效率(WUE)则先升后降.Pn下降的原因短期内以气孔限制为主,长期则以非气孔限制因素为主,且树种耐盐性越弱,NaCl浓度越高,由气孔限制转为非气孔限制的时间越早.试验中,沙棘幼苗在600mmol·L-1NaCl处理10d时即出现盐害症状,22d时全部死亡,而银水牛果可以忍耐600mmol·L-1NaCl长达30d以上,说明银水牛果作为引进树种,其耐盐性较沙棘更强,可能更适合在我国盐碱地大面积推广种植.
With two-year old seedlings of Hippophea rhamnoides and Shepherdia argentea as test materials, this paper studied their growth and photosynthetic characteristics under the stress of different concentration （0, 200, 400 and 600 mmol·L^-1 ） NaCl. The results showed that the biomass and total leaf area per plant of H. rhamnoides and S. argentea seedlings decreased significantly with increasing NaCl concentration. Comparing with the control, the root/shoot ratio of H. rhamnoides and S. argentea seedlings under NaCl stress increased obviously, while the leaf mass per area decreased slightly. When the NaCl concentration increased and the stress time prolonged, photosynthetic rate （Pn）, （LMA） the net transpiration rate （ Tr ）, and stomatal conductance （ Gs ） of H. rhamnoides and S. argentea seedlings declined markedly, the intercellular CO2 concentration （Cj） increased after an initial decrease, whereas the water use efficiency （WUE） and stomatal limiting value （Ls ） decreased after an initial increase. The dynamic changes of Gs, Ci and Ls indicated that the decline of P, was mainly caused by the stomatal limitation in a short-term stress, and by non-stomatal limitation in a long-term stress. The poorer the salt tolerance of tree species and the higher the NaCI concentration, the earlier the transition from stomatal limitation to non-stomatal limitation would occur. As for H. rhamnoides, its morphological symptoms of salt injury appeared on the 10th day, and all of its seedlings were died on the 22th day under 600 mmol NaCl·L^-1 stress. In contrast, S. argentea could tolerate 600 mmol NaCl·L^-1 stress for above 30 days, illustrating that S. argentea, as an introduced tree species, had higher salt tolerance than H. rhamnoides, and could be planted widely in saline regions of China.
出处
《应用生态学报》
CAS
CSCD
北大核心
2009年第4期791-797,共7页
Chinese Journal of Applied Ecology
基金
国家“十一五”科技支撑计划项目(2006BAD03A1203)
高等学校博士学科点专项科研基金项目(20070022028)资助
关键词
NACI胁迫
生长
光合特性
沙棘
银水牛果
NaCl stress
growth
photosynthetic characteristics
Hippophea rhamnoides
Shepherdia argentea.
