NaCl胁迫对5个树种叶肉细胞超微结构的影响

通过对5个树种受不同浓度NaCl胁迫后叶肉细胞超微结构的研究,以揭示其耐盐性。结果表明(:1)0.3%盐胁迫下5个树种叶绿体数目均有所减少,细胞内出现降解物。黄连木、木栓榆、厚叶榆的叶肉厚度增加,榉树、醉翁榆叶肉厚度变薄。榉树发生质壁分离,膜系统紊乱;醉翁榆细胞核边缘模糊,细胞质中出现膜状结构;厚叶榆、木栓榆细胞壁变形;黄连木细胞质膜内陷,细胞核膜边缘模糊。(2)在各自致死盐浓度胁迫下,榉树和醉翁榆细胞物质严重降解,叶绿体明显减少,膜系统增加,细胞质壁分离,细胞核、线粒体降解;厚叶榆、木栓榆细胞内降解物增多,细胞核、蛋白体和线粒体均降解,叶绿体变形,液泡破裂。黄连木叶细胞质壁分离,线粒体、叶绿体解体,细胞中出现大量泡状结构和膜片层。     

低温胁迫过程中北海道黄杨叶肉细胞Ca2+的动态变化

用焦锑酸钙沉淀的电镜细胞化学方法,研究露天生长的北海道黄杨低温胁迫过程中叶肉细胞Ca2+的动态变化.结果表明:与夏季的叶肉细胞相比,从11月份到翌年1月期间,Ca2+沉淀颗粒起初主要分布在细胞间隙和液泡,细胞质中有少量的Ca2+沉淀颗粒,大多数叶绿体中的淀粉粒消失,嗜锇颗粒增加;随后逐渐变化为胞间隙和液泡中Ca2+沉淀颗粒减少,而细胞质基质的Ca2+沉淀颗粒显著增加.在此期间叶肉细胞的一些叶绿体膜泡化,出现解体现象;线粒体的数量增加;中央大液泡变成数个小液泡.低温胁迫过程中叶肉细胞Ca2+的浓度和分布的变化与细胞超微结构的变化存在一定的相关性.     

文冠果体细胞胚发生中钙的超微细胞化学定位

用电镜细胞化学定位的方法,对文冠果种胚诱导体细胞胚发生过程中非胚性愈伤组织、胚性愈伤组织及球形胚、鱼雷胚发育期间Ca2 的分布动态进行超微结构水平上的定位比较研究.结果表明:非胚性细胞Ca2 的含量最少,集中分布在细胞壁和细胞间隙中;胚性愈伤组织的细胞Ca2 的含量明显增加,集中分布在液泡膜、质膜和细胞质中;球形胚时,质膜上Ca2 积累的颗粒较大,但量相对较少;鱼雷胚期ca2 的含量明显增多,集中分布在胚芽端和胚根端,胚根最外层细胞的外侧的细胞壁明显增厚,其细胞壁的外侧Ca2 分布多.推测Ca2 与文冠果体细胞胚发生过程中细胞的发育时期密切相关.     

氮沉降对低磷胁迫下毛竹实生幼苗生长及土壤化学特性的影响

为了探究氮沉降对低磷土壤化学性状及毛竹Phyllostachys edulis实生幼苗生长的影响,以毛竹实生幼苗为材料,设计了4个不同的土壤磷水平P0(2.29 mg·kg-1)、P1(5 mg·kg-1)、P2(7.29 mg·kg-1)、P3(10 mg·kg-1),同时模拟了3个不同的氮沉降水平N0(0 kg·h...     

Cytochemical localization of H+-ATPase and sub-cellular variation in mesophyll cells of salt-treated Cyclocarya paliurus seedlings

Cyclocarya paliurus seedlings of three provenances were treated with three levels of salt (0, 51.0 and 85.0 mmol/L NaCl) in a hydroponic system of a phytotron. The ultrastructural distribution of H⁺-ATPase activity and ultrastructural variation were investigated in mesophyll cells of C. paliurus seedlings after 12 or 20 days of salt treatment. The results showed that under normal growing conditions, H⁺-ATPase activity was low and localized mainly in the nucleus. After 12 days of salt treatment and an increase in salinity, we found that the greater the H⁺-ATPase activity, the lighter the damage suffered by mesophyll subcells after 20 days of salt treatment and the stronger the salt-adaptation ability of seedlings. The location of H⁺-ATPase, largely in the nucleus, indicated that salt-damage suffered by the seedlings was light, whereas its presence, mainly in the vacuoles, showed that salt-damage was more serious. Our preliminary conclusion is that the salt-tolerance level of C. paliurus seedlings for the three kinds of provenances was in the following order, from high to low: Huangshan seedlings from Anhui Province > Kunming seedlings from Yunnan Province > Jiujiang seedlings from Jiangxi Province.     

Seasonal and genotypic variation of water-soluble polysaccharide content in leaves of Cyclocarya paliurus

Cyclocarya paliurus (Batal) Iljinskaja is an important medicinal woody plant due to numerous bioactive natural products in its leaves. As an important bioactive natural product, water-soluble polysaccharides (WSP) in leaves of C. paliurus possess diverse biological activities, such as hypoglycemic, anticancer and free-radical-scavenging activities. To better understand accumulation patterns of WSP in C. paliurus leaves, seasonal, genotypic and positional variations of WSP content were investigated in this study. The results showed that the mean content of WSP in leaves from three crown positions (upper, middle and lower) within an individual was 38.5?mg g^?1. ANOVA and Duncan's multiple range test indicated that WSP content in leaves of the upper crown was significantly higher than that in the middle and lower crowns, whereas no significant difference was observed between the middle and the lower positions. Seasonal variation of WSP content in the leaves was revealed as a bimodal temporal pattern with the maximum (38.3?mg g^?1) observed in April and the second peak (32.3?mg g^?1) in October, whereas the lowest WSP content was observed in June (20.12?mg g^?1) or in fallen leaves (17.71?mg g^?1). Generally, higher contents of WSP accumulated in the maturity/senescence period (from September to mid-November) than during the rapid growth phase (from May to August). Moreover, WSP content varied significantly among 12 provenances, ranging from 22.09 to 34.56?mg g^?1, in leaves sampled in October. Our results not only provide knowledge of the accumulative dynamics and genotypic variation of WSP, but also establish a basis for determining the optimal time for harvesting and for extensive selection and breeding programs to improve the content of beneficial compounds in the leaves of C. paliurus in the future.     

Genotypic variation in tree growth and selected flavonoids in leaves of Cyclocarya paliurus

Cyclocarya paliurus is a valuable medicinal tree species in China. However, limited information is available on its genotype selection and cultivation for improvement of growth and health-promoting phytochemicals. To contribute to improved knowledge of the potential use of the species, 33 families of C. paliurus were assessed with respect to genotype on growth and flavonoid content in the leaves, and the relationship between growth and flavonoid accumulation was examined. Growth and flavonoid content varied significantly among different families, and isoquercitrin was the main component of the individual flavonoids, followed by kaempferol and quercetin. Both total and individual flavonoids showed seasonal variation, with the mean highest contents of quercetin and isoquercitrin in July but the highest kaempferol content in October. Correlation analysis showed that tree height and diameter at breast height of C. paliurus were negatively correlated with the contents of quercetin and kaempferol in the leaves, whereas no significant correlation between tree growth and total flavonoid content was detected. Hierarchical cluster analysis based on the parameters of tree growth and leaf flavonoid contents indicated that 33 families of C. paliurus were classified into four distinct groups. Results from this study are valuable for identifying superior families for a specific site and provide a basis for C. paliurus breeding strategies for flavonoid production.     

Effect of NaCl stress on ion distribution in roots and growth of Cyclocarya paliurus seedlings

We studied ion distribution in roots and the growth of Cyclocarya paliurus seedlings of three provenances, Huangshan in Anhui, Jiujiang in Jiangxi and Kunming in Yunnan, under conditions of 0, 1, 3 and 5 g/L NaCl stress using X-ray microanalysis. Results show that under NaCl stress of 3 and 5 g/L, the relative contents of Na⁺ and Cl⁻ in root tissues increased, while the relative contents of K⁺, Ca²⁺ and Mg²⁺ decreased. With an increase in salinity, the relative content of Na⁺ in the epidermis and cortex of the root increased, while the relative content of Cl⁻ in the stele and cortex of the root increased markedly. Thus, ions in the root tissues were unbalanced and the ratios K⁺/Na⁺ and Ca²⁺/Na⁺ decreased, while Na⁺/(K⁺+ Na⁺+Ca²⁺+Mg²⁺) increased. The decrease of the K⁺/Na⁺ ratio and the substantial increase of Cl⁻ in root tissues contributed to a decline in seedlings survival and reduced the increments for seedling leaf area, height, basal diameter as well biomass. Our preliminary conclusion is that the level of salt tolerance for the tested provenance seedlings was in the order of Huangshan > Kunming > Jiujiang, and the threshold of salt tolerance for C. paliurus seedlings was about 1 g/L. __________ Translated from Scientia Silvae Sinica, 2008, 44(6): 66–72 [틫自: 쇖튵뿆톧]