两种沉水植物在不同水深和生长时期对入侵植物的响应

为研究沉水植物在不同水深和生长时期对不同种类入侵植物的响应,选取2种湿地入侵植物凤眼莲Eichhornia crassipes、水盾草Cabomba caroliniana和2种常见本地沉水植物黑藻Hydrillaverticillata、菹草Potamogeton crispus为研究对象,通过模拟试验探究在不同水深（0.2、0.4 m）和生长时期（生长初期和生长旺期）的本地沉水植物对2种入侵植物的响应。结果显示,当水深为0.4 m时更有利于黑藻的生长,并可削弱入侵植物对黑藻生长的消极作用,而水深对菹草的生长无显著影响;入侵植物种类对本地沉水植物的生长无显著影响,但影响方式却存在差异,其中水盾草倾向于直接抑制本地沉水植物的生长,而凤眼莲可以通过降低水体透明度以及总磷含量进而间接抑制本地沉水植物的生长。此外,外来植物在本地沉水植物生长初期入侵对本地沉水植物产生的消极影响较生长旺期入侵时更显著。表明凤眼莲及水盾草入侵对本地沉水植物生长的影响机制存在差异,本地沉水植物在适宜水深和生长旺期对2种入侵植物具有更强的抵抗能力。     

用凤眼莲(Eichhornia crassipes Solms)去除废水中氮、磷元素的功效及其相关因素的研究

在含Ag~+浓度为0.1～2.0ppm的屠宰废水中,凤眼莲降低N、P元素的效率,随浓度增加而降低;当Ag~+浓度为2ppm时,凤眼莲降低N、P元素的效率,随处理时间的延长而增加。去除N的百分率低于P的百分率。屠宰废水中的Ag~+浓度高达15ppm时,凤眼莲植株在24小时内坏死。不同Ag~+浓度的废水对凤眼莲根系脱氢酶活力水平的影响大小不同,从而影响到N、P元素的去除效率。实验结果为利用凤眼莲净化屠宰废水,富集回收水环境中的银,提供了重要依据。     

Multiple dietary administrating strategies of water hyacinth (Eichhornia crassipes) on enhancing the immune responses and disease resistance of giant freshwater prawn,Macrobrachium rosenbergii

The different products of Eichhornia crassipes leaves including dried E. crassipes powder (DEP), hot‐water treated E. crassipe (HTE), hot‐water extract of E. crassipe (ECE) and dreg of hot‐water extract of E. crassipe extract (dECE) were produced and incorporated into the diet of the prawn, Macrobrachium rosenbergii, as an immunostimulant. Results showed that prawn fed the HTE‐, ECE‐ and dECE‐containing diets for 4 months had increased total haemocyte count, different haemocyte count, phenoloxidase activity, respiratory bursts, superoxide dismutase activity, glutathione peroxidase activity especially in HTE and ECE treatments. The phagocytic activity and clearance efficiency against Lactococcus garvieae of prawn fed the HTE‐ and ECE‐containing diets were significantly higher than those of prawn fed the control diet at 2–4 months. The relative percentage survival of prawn fed the DEP‐, HTE‐, ECE‐ and dECE‐containing diets for 4 months following 144 h challenging with L. garvieae were 19.0%, 38.1%, 38.1% and 33.3%. It was concluded that E. crassipes leaves containing an active component which was easily extracted by hot water can enhance innate immunity and resistance against pathogen of M. rosenbergii by dietary long‐term administration, and the administration of HTE in the diet was the best strategy due to the availability and convenience.     

Occurrence and diversity of fungal pathogens associated with water hyacinth and their potential as biocontrol agents in the Rift Valley of Ethiopia

Water hyacinth poses serious socio-economic and environmental problems in Ethiopia. To integrate fungal pathogens into water hyacinth management, a survey was conducted in the Rift Valley of Ethiopia. Based on morphological characterization and DNA sequencing, 25 fungal species were identified that belong to nine genera. Alternaria tenuissima, A. alternata, Aspergillus niger, Phoma sp., Curvularia trifolii, Mucor fragilis, M. racemosus, A. fumigatus, Fusarium oxysporum, and F. equiseti were the most common fungi detected. However, their occurrence was influenced by water wave action, temperature, season, and altitude. Among the fungal pathogens, A. alternata, A. tenuissima, F. oxysporum, F. equiseti, and Neofisicoccum parvum were highly pathogenic to water hyacinth. Alternaria alternata and A. tenuissima did not cause disease symptoms on ecologically important plant species (e.g. Noug, Tef, and Coffee). Application of the fungal pathogens on water hyacinth plants also showed 11%–67%, 22%–72%, 15%–55%, and 12%–50% reduction in fresh weight, dry weight, plant height, and root length of water hyacinth, respectively. This study suggests that fungal species have the potential to control water hyacinth biologically and provides baseline data for biological control efforts in the future.     

凤眼莲的胚胎学研究Ⅲ.受精作用和胚胎发育

本文报道了凤眼莲的受精过程及胚和胚乳的发育。授粉后3～8小时,花粉管穿过花柱;17～21小时,花粉管经珠孔到达胚囊;约48小时,一个精子进入卵细胞;3天完成受精作用;5天出现两细胞原胚。胚的发育属紫菀型,经历原胚、球型胚、椭圆形胚、凹形胚、棒形胚等各个时期。凤眼莲的胚乳发育属沼生目型,授粉后约19～21小时,另一精于与次生核融合形成游离核;2～5天形成大量的胚乳游离核;6天开始形成胚乳细胞壁。约20～21天,种子成熟,种子含胚和胚乳。     

3种入侵植物叶绿素荧光特性的研究

[目的]研究入侵植物的叶绿素荧光特性。[方法]以3种入侵植物水葫芦、大藻和空心莲子草为材料，利用调制叶绿素荧光技术对其叶绿素荧光特性进行比较。[结果]结果表明，在弱光下（200μmol/m^2·s）空心莲子草实际光合效率（PSII）和快速光曲线的初始斜率（d）都高于大藻和水葫芦，但强光下（800μmol/m^2·s）空心莲子草的PSII和相对电子传递速率（rETR）受到显著抑制，大藻抑制程度较低，而水葫芦的耐受性最强。通过快速光曲线发现，在变化的光强环境中，水葫芦的适应能力最好，大藻次之，而空心莲子草最差。强光下水葫芦和大藻非光化学淬灭（NPQ）的主要组分是能态淬灭（qE），而空心莲子草的主要组分是qE和状态转换淬灭（qT）。3种入侵植物中水葫芦的适应能力最强，大藻次之，空心莲子草最低。空心莲子草尽管在强光下受到了损伤，但仍具备较高的光保护能力来助其“过冬”。这些特性可能与植物的入侵性有密切关系。[结论]该研究为探讨入侵植物维持能量平衡的能力与入侵性的关系提供参考。     

水葫芦沼液对青菜生长及AsA-GSH循环影响的动态研究

以青菜为材料,研究了在青菜整个生长周期内,不同比例水葫芦沼液对青菜生长的影响及其体内AsA-GSH循环影响的动态变化.结果表明,使用不同比例沼液代替化肥对青菜的株高及生物量产生不同的影响,其中,以25%沼液替代化肥的处理效果最好,在不同的采样时期,其株高和生物量均显著大于对照,当沼液使用比例大于50%时,株高和生物量均...     

外来入侵植物对赤潮的生态调控作用

利用外来入侵植物凤眼莲对赤潮进行生态调控取得了很大进展。从外来入侵植物的入侵机制、外来入侵植物对赤潮生态调控的应用基础和外来入侵植物对赤潮生态调控作用研究进展等若干方面进行了综述。     

污水净化过程中凤眼莲根区微生物的变化

研究了凤眼莲净化污水时,根区微生物的动态变化.结果表明:温度制约着凤眼莲及其根区微生物的净化效能,随温度升高,净化速度加快.凤眼莲根区细菌总数始终高于真菌总数,在污水净化中表现为主导作用.污水净化初期凤眼莲根表微生物增长迅速,随污水的不断净化,微生物逐渐减少,净化后期部分水体微生物呈现2次增长现象.     

凤眼莲净化北方地区屠宰废水的初步研究

对凤眼莲净化北方地区屠宰厂废水的效果进行了初步研究。结果表明：在适宜的温度条件下，凤眼莲可以直接净化高浓度的屠宰废水，能够大幅度降低屠宰废水中的化学需氧量、悬浮物、氨态氮和总磷的浓度。凤眼莲处理系统在去除水中有机污染物的同时，还可收获大量具有多种用途的凤眼莲。