【摘要】 以0、50、100、150、200和250mmol·L-1NaCl的1/2 Hoagland营养液处理长春花(Catharanthus roseus)幼苗5d,测定其生物量,根、茎及叶中不同组织细胞中无机离子相对含量,叶绿素含量及光合生理指标。结果表明:NaCl能显著降低长春花幼苗的鲜质量和干质量;对根、茎和叶片横切面X射线微区分析表明,NaCl胁迫导致长春花体内各组织细胞中Na+和Cl-相对含量显著增加,但在各器官、组织中分布稍有不同:与对照相比,根和茎中都是表皮细胞中增加幅度最大,中柱细胞次之,皮层细胞最低;在叶片中亦是表皮细胞增加幅度最大,依次是皮层细胞、海绵组织细胞及栅栏组织细胞。NaCl胁迫下,K+和Ca2+相对含量对其的响应特征在不同器官中亦不相同:与对照相比,在根和茎皮层及中柱细胞中的下降幅度低于表皮;而叶中则是栅栏组织细胞最低。盐胁迫能够抑制长春花幼苗生长,打破其体内的离子平衡,但植物为降低盐胁迫的伤害而将过多的Na+和Cl-聚集于表皮细胞。NaCl胁迫下,长春花幼苗叶绿素含量、光合速率(Pn)、细胞间隙CO2浓度(Ci)、气孔导度(Gs)、蒸腾速率(Tr)显著降低,气孔限制值(Ls)升高,说明气孔限制是降低长春花幼苗光合速率的主要因素。更多还原

【Abstract】 Catharanthus roseus seedlings were treated with 1/2 Hoagland solutions containing different concentrations (0, 50, 100, 150, 200, and 250 mmol·L-1) of NaCl. After 5-day treatment, the seedlings biomass, relative contents of inorganic ions in cells of different tissues, leaf chlorophyll content, and photosynthetic parameters were estimated. The results showed that NaCl stress decreased the seedlings fresh mass and dry mass significantly. Under NaCl stress, the relative contents of Na+ and Cl-in cells increased significantly, but the increment somewhat differed with different tissues. In root and stem, epidermal cells had the greatest increment, followed by cortex cells, and stelar cells; while in leaf, epidermal cells had the greatest increment, followed by cortex cells, spongy tissue cells, and palisade tissue cells. The relative contents of cell K+ and Ca2+ were decreased under NaCl stress, and the decrement was also differed with different tissues. In root and stem, epidermal cells had the greatest decrement, followed by cortex and stelar cells; while in leaf, palisade tissue cells had the greatest decrement. In a word, NaCl could inhibit the growth of C. roseus seedlings, and disrupt their ion balance. To avoid the damage caused by NaCl stress, the seedlings would congregate excessive Na+ and Cl-in their epidermal cells. Under NaCl stress, the chlorophyll content, photosynthetic rate (Pn), intercellular CO2 concentration (Ci), stomatal conductance (Gs) and transpiration rate (Tr) decreased while stomatal limiting value (Ls) was in adverse, indicating that stomatal limiting was the main factor reducing the photosynthetic rate of C. roseus seedlings.更多还原