尿素和精喹禾灵不同配施对紫苏光合性能和产量的影响

采用随机区组试验设计,研究尿素(0,1,2,4和8g/L)与10.8%精喹禾灵乳油(0,0.8,1.6,2.4和3.2mL/L)不同配施对紫苏光合、叶绿素荧光特性、除草效果和产量的影响.结果表明:精喹禾灵与8g/L尿素配施可显著降低紫苏的光合特性、光系统Ⅱ的实际光化学效率和产量;而精喹禾灵与1~4g/L尿素配施均有高于单用精喹禾灵处理的趋势.A组的Q1N3处理(先施4g/L的尿素再施0.8mL/L的精喹禾灵)效果最佳,能显著提高紫苏在精喹禾灵胁迫下的光合性能,增强紫苏对光破坏的防御机制,增产10.54%.表明精喹禾灵可对紫苏产生胁迫,尿素可缓解其对紫苏的伤害.     

Mechanisms of Hydroquinone-Induced Growth Reduction in Leafy Spurge

Field observations indicate leafy spurge (Euphorbia esula) is inhibited by the presence of Antennaria microphylla. Hydroquinone (HQ), one of several compounds isolated from A. microphylla has been shown to inhibit leafy spurge seed germination, root elongation, and callus culture growth. The present study was designed to analyze the effects of HQ on water relations and photosynthesis of leafy spurge. Plants grown in 0.25 mM HQ had consistently higher leaf diffusive resistance and lower transpiration rates than control plants (P < 0.05). Chlorophyll fluorescence was significantly lower than controls (P < 0.05) towards the end of the treatment period. At the end of the treatment, tissue from 0.25 mM HQ plants had higher levels of ¹³C, indicating there had been a sustained interference with stomatal function. These data suggest that a disruption of the plant water balance is one mechanism of leafy spurge inhibition by A. microphylla.     

Structural Insight into the Complex of Ferredoxin and [FeFe] Hydrogenase from Chlamydomonas reinhardtii

The transfer of photosynthetic electrons by the ferredoxin PetF to the [FeFe] hydrogenase HydA1 in the microalga Chlamydomonas reinhardtii is a key step in hydrogen production. Electron delivery requires a specific interaction between PetF and HydA1. However, because of the transient nature of the electron‐transfer complex, a crystal structure remains elusive. Therefore, we performed protein–protein docking based on new experimental data from a solution NMR spectroscopy investigation of native and gallium‐substituted PetF. This provides valuable information about residues crucial for complex formation and electron transfer. The derived complex model might help to pinpoint residue substitution targets for improved hydrogen production.     

微藻光合转化甲酸生产蛋白质的研究

蛋白质是重要的食品原料,其高质量稳定供应对提升人民生活水平和保证国家粮食战略安全至关重要。目前中国对蛋白质的进口依存度较高,急需高效的非粮来源高品质蛋白质的生产技术。近年来莱茵衣藻（Chlamydomonas reinhardtii, C. reinhardtii）作为一种显著增长的可食用蛋白质资源受到广泛关注,但其主要以乙酸为碳源进行异养发酵,无法利用其光合作用在绿色生物制造方面的优势。作者利用CO₂清洁能源还原产物甲酸作为强化碳源,探索甲酸提高C. reinhardtii光合生产效率的可行性。基于HCOO^-对光合活性的抑制作用,以叶绿素荧光动力学参数为依据,通过逐步提升培养基中HCOO^-浓度,获得HCOO^-耐受浓度达到150 mmol/L的驯化藻株。在50~150 mmol/L的HCOO^-下,驯化藻株的光系统Ⅱ的最大量子产率（F_v/F_m）以及光合作用相关的多不饱和脂肪酸的质量分数维持稳定。在相同培养条件下,接近于乙酸添加的培养效率,蛋白质的质量分数为30%~35%,达到或超过常规衣藻乙酸发酵产品的蛋白质质量分数。该研究在人工光合杂化高效转化CO₂的背景下,提供了一种以甲酸为原料快速生产C. reinhardtii蛋白质的技术路线,也为绿色生物制造提供了一种新的技术选择。该研究所获得的高浓度HCOO^-耐受藻株,为探索光合活性调控机制提供了理想的研究对象。     

A tubular bioreactor for photosynthetic production of biomass from carbon dioxide: Design and performance

A theory of photobioreactor design is developed. A photobioreactor was constructed in the form of a loop made from 52 m of glass tubing of 1 cm bore; the loop covered about 0.5 m². The culture was illuminated with mercury halide lamps to reproduce sunlight. Computer control was used to maintain constant biomass concentration. The influence of radiation on the reactor temperature is quantitatively predicted. An air lift system was preferred to a liquid pump for culture recycle. The energy required for culture recycle in the loop with Reynolds number 2000 was 0.6 W m^?2. The CO₂ gas/liquid transfer rate achieved was sufficient to meet the maximum possible demand with solar irradiation. The O₂ gas/liquid transfer rate was sufficient to meet the maximum respiration demand at night. The maximum algal biomass concentration achieved exceeded 20 g dry weight litre^?1. A biomass concentration of 8 g dry weight litre^?1 was found to be convenient for normal operation. The maximum uptake of light in the available wavelength range (400–700 nm) was 38 W m^?2, this corresponds to utilisation of solar irradiation up to 89 W m^?2. Below the maximum light uptake rate the efficiency of storage of light energy in the biomass corresponded to 16.6% of solar energy.     

广西优质红锥种质资源光合特性的分析

本研究对广西优质红锥种质资源的光合特性进行了系统分析。结果表明：10个红锥品系光合速率均呈双峰曲线,于10：30和16：30达到最高峰,其中浦北品系光合速率最高,东兰品系光合速率最低。叶绿素含量以浦北品系最高,东兰品系最低。     

大豆N2O释放与光照度和光合作用的关系

采用分隔式封闭箱法,测定盆栽大豆植株氧化亚氮(N2O)通量以及光照度、光合速率和气孔导度的日变化。同时,观测田间大豆—土壤系统在主要生长阶段N2O释放的变化。在温室里,大豆植株N2O释放在上午10:00时出现一个高峰;中午时N2O释放量较低,此时光照度和光合速率都保持在较高的水平上;在14:00时,N2O释放量达到低谷,光照度达到最大,但光合速率却处于很低的水平;在15:00时,植株N2O的释放达到第二个高峰,但光照度和光合速率却处于快速下降期。结果表明:植物N2O的释放不仅与光合作用的光反应有关,而且也与暗反应有关。上午10:00以后植株N2O释放通量与气孔导度变化没有一致的关系。在大豆生长季,大豆—土壤系统N2O释放通量有两个高峰,第一个峰出现在6月中下旬,第二个高峰出现在9月下旬。