碱性盐胁迫对宁夏枸杞生长、结构及光合参数的影响

Effects of alkali stress on growth,structure and photosynthetic parameters of Lycium barbarum L.

采用盆栽试验,对碱性盐(NaHCO_3)胁迫下枸杞生长、叶片解剖结构、超微结构以及光合参数进行了研究。结果显示:随着NaHCO_3胁迫浓度的增加,净生长量呈先增加后降低的趋势,地上部干重、地下部干重和整株干重总体呈下降趋势,根冠比呈上升趋势;叶肉栅栏组织在低浓度NaHCO_3处理(150 mmol·L-1)时排列比较紧密,随着胁迫浓度增加,栅栏组织的细胞层数逐级减少,细胞结构紧密度逐渐降低,叶片厚度、上下表皮厚度及晶体数呈现先增后降的趋势;超微结构显示,随着胁迫浓度的升高,叶肉细胞形状变的不规则,叶绿体结构变形,基粒片层排列紊乱,淀粉粒增多;净光合速率(Pn)、蒸腾速率(Tr)、气孔限制值(Ls)和气孔导度(Gs)随NaHCO_3浓度的升高呈下降趋势,胞间CO_2浓度(Ci)呈升高趋势,水分利用效率(WUE)呈先升后降的趋势;相关分析显示,盐胁迫强度与净生长量、生物量、净光合速率、蒸腾速率、气孔导度和气孔限制值呈负相关关系,与净光合速率、蒸腾速率和气孔导度呈显著负相关关系(P<0.05)。由此说明,碱性盐胁迫改变了叶片的功能性状,促使枸杞光合作用下降,直接影响干物质积累及株高的生长。

To reveal the relationship between the growth,structure,photosynthesis,and the potential mechanism of salt-alkali resistance of Lycium barbarum L.,the growth,anatomical structure,ultrastructure and photosynthetic parameters were investigated under alkali stress in pot experiments. The results showed that with the increase in concentration of NaHCO_3,the net height first increased and then decreased,the top dry weight,the root dry weight,and the whole dry weight decreased,and the root to top ratio increased. With the increase in concentration of NaHCO_3,the number of cell layer of palisade tissue and the cell structure compactness decreased,and thickness of leaves,upper Epidermis thickness,lower Epidermis thickness and crystal number first increased and then decreased. With the increase in concentration of NaHCO_3,irregular form of mesophyll cell,deformation of chloroplast,disrupted granum lamellae and increased starch number were observed. The net photosynthetic rate( Pn),stomatal conductance( Gs),transpiration rate( Tr),and stomatal limitation( Ls) decreased,and intercellular CO_2 concentration and water use efficiency( WUE) first increased and then decreased when the concentration of NaHCO_3 increased. Plant net growth increment,whole plant-biomass accumulation,Pn,Tr,Ls and Gs were negatively correlated to alkali stress intensity,and significantly negative correlations was found between Pn,Tr,Gs and alkaline stress intensity of Lycium barbarum L. The results suggested the functional traits of Lycium barbarum L. were inhibited by higher NaHCO_3 stress,which reduced the photosynthesis,and thus ultimately a decrease in biomass accumulation and the growth was brought about.