Experimental evaluation of a composted seaweed extract as microalgal culture media

An organic culture media based on a composted liquid seaweed extract was developed and tested for growth of Chaetoceros muelleri. The extract was evaluated at two concentrations and then compared with two commercial media: Walne and agricultural fertilizer (AF). The concentrations of nitrogen and phosphorous differed between the two commercial media and the seaweed extract; however, growth of Chaetoceros muelleri was similar. The successful culture of Chaetoceros muelleri in composted liquid seaweed extract suggests the feasibility of and potential use for this natural, organic fertilizer in aquaculture. The seaweed extract is simple to obtain and inexpensive.     

近缘新对虾幼体的饥饿、摄食和食性

本文于1987、1988两年近缘新对虾的繁殖季节,研究了早期饥饿对近线新对虾幼体发育、变态的影响,饥饿时间与幼体变态时间的关系;幼体及后期幼体各阶段摄食卤虫无节幼体、褶皱臂尾轮虫数量的变化;幼体各阶段的适宜饵料种类及密度。     

慈竹材物理力学性质研究

对四川江油1～3年生慈竹材主要物理力学性质进行了测定与分析,结果显示:竹材气千密度,全干密度,基本密度,顺纹抗压强度,顺纹抗剪强度随竹龄和竹秆高度的增加而增加:径、弦向全干缩率随竹龄和竹秆高度的增加而减小:径向全千缩率大于弦向:竹壁厚度随竹龄的增加而增厚,随竹秆高度的增加而减小.方差分析表明,竹材全干密度,基本密度,径、弦向全干缩率,顺纹抗压强度随竹龄变化在0.001水平显著;全千密度,竹壁厚度,顺纹抗剪强度随竹秆高度变化在0.001水平显著.     

磷浓度对盐生杜氏藻和纤细角毛藻叶绿素荧光特性及生长的影响

在温度(23±1)℃,盐度31,光照度5000 lx的条件下,用含有不同磷浓度(0、2.27、18.15、36.3、72.6、290.4μmol/L)的培养基对盐生杜氏藻和纤细角毛藻进行培养,研究2种微藻在一次性培养过程中,不同磷浓度对其PSII最大光能转化效率(Fv/Fm)、叶绿素含量以及细胞密度的影响。单因子方差分析结果表明,在整个培养周期中,磷浓度对两种微藻的光合作用及生长均有显著影响(P<0.05)。盐生杜氏藻的PSII最大光能转化效率、叶绿素含量以及细胞密度均随着起始磷浓度的增加而增加,在290.4μmol/L处达到最大值;纤细角毛藻的PSII最大光能转化效率、叶绿素含量以及细胞密度在18.15μmol/L处达到最大值,而后随着磷浓度的继续升高,其上述指标反而降低。所以盐生杜氏藻和纤细角毛藻进行光合作用和生长的最适磷浓度分别为290.4μmol/L和18.15μmol/L。     

Mass production of microalgae in six commercial shrimp hatcheries of the Mexican northwest

A 2-year survey in six commercial shrimp hatcheries of the states of Sonora and Sinaloa, in the Mexican northwest, aiming to investigate the variability of the outdoor biomass production and composition of microalgae showed wide differences in daily mean yields, from 0.68 to 1.71×10¹² cells m⁻³ and between 23.9 and 73.9 g m⁻³ of dry organic biomass.

These differences were mostly related to the type of culture containers and consequent differences in light penetration. The best yields were in 0.7 m deep polyethylene tanks and the lowest in 1 m deep concrete tanks with a small surface to volume ratio.

Protein, carbohydrate and lipid yields followed the same trends as biomass production and were mostly associated with the design of the culture containers and, in part, with the geographic location of the hatcheries.

Variability was high also within laboratories, and this was related to seasonal climatic differences. In Sonora, cell concentrations were negatively related to temperature, but organic biomass production increased with the increase of this climatic variable, probably because of larger cell sizes. In contrast, the data obtained in Sinaloa showed that cell concentration and organic biomass are directly related to temperature and inversely to light.

Proteins and lipids were negatively related to temperature in Sonora but not in Sinaloa, where high carbohydrates were associated with low temperatures.

Fatty acid profiles were highly variable in all cases and were not associated with the type of culture containers or, with the possible exception of 18C unsaturates, with the geographic location of the laboratories, indicating as probable sources of variability between and within hatcheries either the handling routines or the composition of the growth media.     

慈竹扦插苗移栽后不同时期的生理适应性

以移栽后不同时间段的慈竹扦插苗叶片为材料,采用石蜡切片技术观察叶片解剖结构,并运用苯酚-硫酸法测定相关的光合特性指标,以探明慈竹扦插苗移栽后对环境的适应情况。结果表明:随着移栽时间的延长,慈竹扦插苗叶片气孔逐渐减小、密度增大;叶片增大、增厚,角质层增厚,上下表皮细胞和泡状细胞面积增大,且泡状细胞下陷深入叶肉的深度加深,梭形细胞面积减小;净光合速率(P_n)增强,而蒸腾速率(T_r)降低;含水量和可溶性总糖含量减少,干鲜质量比、淀粉含量及淀粉粒数量增多。移栽后的慈竹扦插苗逐渐积累光合产物,植株对环境的适应能力不断增强,移栽3个月后的慈竹扦插苗与完全适应环境的3年生慈竹扦插苗的叶片结构和光合特性指标较接近。慈竹扦插苗在移栽后的3个月内需采取合理的管护措施,避免过度失水,以提高慈竹扦插苗移植成活率。     

广州河涌城市废水暴露致食蚊鱼组织病理学变化

对生长在广州海珠涌和黄埔涌中食蚊鱼（Gambusia affinis）目标器官组织结构变化进行观察,调查广州河涌污染现状及对食蚊鱼的毒性效应,探究利用鱼类作为指示生物去评价城市河涌水污染的现状。选取宝岗大道、洪德、赤岗和苗艺路段4个采样点,并设置对照点。食蚊鱼采集分别于2012年12月（冬季）和2013年6月（夏季）进行,每个采样点的食蚊鱼总数在200尾以上。使用水质监测仪测定各采样点的水质参数,包括pH值、温度、电导性和溶解氧。对食蚊鱼的肝脏、性腺、鳃和肠等器官进行石蜡组织切片,H-E染色,荧光倒置相差显微镜下观察并拍照。结果表明,海珠涌和黄埔涌水污染严重,属IV或V类水质。仅苗艺路段冬季的溶解氧高于5 mg/L,其余采样点溶解氧为1?3 mg/L。食蚊鱼由于供氧不足,其生长发育受到严重影响。主要器官组织出现不同程度的形态结构变异：肝细胞界限模糊,毛细血管扩张充血,部分肝细胞空泡化,出现一定数量黄棕色色素细胞团。多数卵母细胞发育停滞在II时相和III时相阶段。鳃小片上皮细胞增生肿大、充血,出现呈球状或棒状的动脉瘤;相邻鳃小片出现融合,鳃丝软骨出现增生和扭曲肿大现象。精巢及肠道则无明显变化。研究结果显示,广州河涌水污染十分严重;食蚊鱼肝脏、性腺和鳃组织对河涌水体污染的毒性反应十分敏感,可以作为监测及评价城市河涌水污染的生物标志物。     

Salinity Preference of Two Diatoms and Their Growth Performance in Three Prepared and Two Alternative On-Farm Media Sources

ABSTRACT

Salinity and preferred nutrient composition of Chaetoceros affinis and Skeletonema costatum were tested. Salinity was tested at 12, 16, 23, 28, and 32 ppt. Three compositions of nitrogen (N), phosphorus (P), and potassium (K) and two on-farm low-cost alternative media sources, cow urine (CU) and hatchery waste water (HWW), were tested to find the suitable NPK ratio and to determine the efficacy of the on-farm media respectively. Chaetoceros affinis preferred 23 ppt salinity, while Skeletonema costatum preferred both 28 and 32 ppt. Among the NPK treatments, higher cell density was observed in 4:1:1 followed by 4:2:1 ratios. Significant differences in maximum cell density of both species were observed in the NPK treatments while only S. costatum showed significant difference in CU and HWW.     

热处理对慈竹重组材性能的影响

以丛生竹类的慈竹竹篾为原料,运用不同的热处理温度对其进行高温热处理并压制慈竹重组材,对热处理前后慈竹的化学组分进行分析,并对慈竹重组材的物理力学性能进行测定。研究结果表明,当热处理温度从190℃上升至210℃后,慈竹化学组分和慈竹重组材力学性质出现急剧的变化,保证力学强度的前提下,考虑户外用材的尺寸稳定性及生物耐久性的要求,可选用热处理温度190℃,热处理时间2 h的热处理工艺。     

慈竹竹叶多糖的提取及纯化工艺

以水为溶剂,以提取时间、温度和料液比3个因素作为研究对象,以多糖提取量为评价指标,在单因素的基础上,通过三因素三水平的Box-Behnken响应面分析法研究了优化多糖的提取工艺条件。结果表明:最优提取条件为提取时间1.43h、温度76.8℃、料液比1∶80.3,在此条件下,多糖得率可达到4.11mg/g。提取液经一系列纯化工艺后,得到纯度为61.32%多糖。