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1.
2010年,作者在辽东半岛成功进行了裙带菜室内常温全人工育苗大规模生产试验,并全程进行了光照强度、温度和配子体发育相关性的研究。研究表明,采用双高光期(≥50μmolphotons/m2·s)调控配子体的生长和发育可达到理想效果。从采苗至度夏前,采用高光照使配子体充分完成营养生长;从度夏结束至幼苗出库前,同样采用高光照,使配子体快速发育形成孢子体并迅速生长。现场观察表明,只要光照强度逾越了诱导发育的阈值,裙带菜配子体在24℃仍然能够正常发育并形成孢子体;幼孢子体能够耐受24~26℃的高温,但是最适生长温度为20~22℃;孢子体越小,耐受高温能力越强。在24~26℃的高温条件下,幼孢子体生长缓慢,较大个体会出现尖端溃烂缺失的现象。在整个育苗过程中,根据温度变化和配子体的显微观察结果因地制宜地对光线进行实时调整。出库前培育的苗帘在幼苗密度、大小和健康方面均达到商业化栽培的要求。 相似文献
2.
不同光强处理对设施桃树光合及荧光特性的影响 总被引:28,自引:1,他引:28
以二年生“春捷”毛桃为试材,研究了日光温室内遮荫处理桃树在不同光照强度条件下光合特性以及荧光特性的变化。结果表明:随着光照强度的降低,桃树叶片的光补偿点、光饱和点、CO2饱和点(CSP)、CO2补偿点(CCP)、Rubisco活性、表观光合量子效率(AQY)、光呼吸速率、乙醇酸氧化酶(GOX)活性和羧化效率(CE)均呈下降趋势;光合色素含量在不同光强条件下变化较大,两个弱光处理叶绿素a(Chl.a)、叶绿素b(Chl.b)、 类胡萝卜素(carotenoids)的含量均比对照升高。不同光强条件对桃树叶片的荧光参数φPSⅡ、Fo和Fv/Fm的日变化影响显著,弱光照处理的φPSⅡ、Fv/Fm的日变化比较平稳而且维持在一个较高的水平,而对照的上述两个参数的日变化波动较大;三个不同光强处理的Fo的日变化均是在10:00开始上升,在13:00达到最高点而后下降,变化趋势基本一致。 相似文献
3.
光是影响水生动物生长和发育的重要环境因子,其在养殖水体中的传播特征仍未明确。本研究选取红光(波峰为645 nm)、绿光(510 nm)、蓝光(445 nm)、UVA(355 nm)以及全光谱(蓝光激发硅酸盐荧光粉辐射的白光波长范围可达400~800 nm)5种LED光源,调整辐射照度为60 W/m2,研究其在不同养殖水质环境中的传播规律,为满足室内工厂化水产养殖对象的光生物学需求,实现养殖光环境标准化调控提供参考。结果显示,5种不同光谱特征的LED光源在深井海水中的透光率随水深增加呈降低趋势,不同光源间变化趋势存在差异。当透光水深为10 cm时,绿光透光率最大,为(46.01±4.03)%,UVA最小,为(26.01±2.53)%;当透光水深为150 cm时,各光色透光率均小于1.5%;5种不同光色的光源在水体中的透光率衰减曲线均符合乘幂函数。水体对LED光的吸收在不同的光谱区域是不同的,具有明显的选择性,水对光谱中红外部分的吸收最为强烈,对可见光谱波段中的红色、黄色和绿色光谱区段的吸收也十分显著;LED光源在养殖水体中衰减严重,水深是影响LED光源在水体中传播的主要因素(P<0.01),其次是总悬浮物(TSS)和化学需氧量(COD),但不同光源在养殖水体中受TSS和COD含量的影响程度不同。光在水体中的衰减由水对光的吸收以及散射作用引起,且光在不同波段的衰减率主要由水生介质的吸收光谱决定。 相似文献
4.
T. Vesala T. Markkanen L. Palva E. Siivola S. Palmroth P. Hari 《Agricultural and Forest Meteorology》2000,100(4)
A set-up with 161 photosynthetically active radiation (PAR) sensors was used to investigate spatio-temporal variations of irradiance for five horizontal arrays within a Scots pine canopy. The measured PAR was converted to CO2 exchange using of a shoot-scale photosynthetic response curve and the vertical distribution of the needle area. The net ecosystem exchange was simultaneously measured by the eddy covariance technique. The effect of spatial and temporal averaging of the PAR values and the number of sensors were analysed under different conditions as regards cloudiness and the shading by the foliage. In 1/2 h CO2 exchange values for the entire canopy, a maximum overestimation of 30% resulted from a spatial averaging over horizontal arrays of 2–5 m and occurred under clear-sky conditions and significant foliage shading. Under partly cloudy conditions, the largest overestimation occurred for a case of little shading and the inaccuracy resulting from 1/2 h temporal averaging exceeded that of spatial averaging. 相似文献
5.
Responses of leaf conductance (g
L) to variation in environmental and plant hydraulic factors were examined on intact and detached shoots of little-leaf linden
(Tilia cordata Mill.) with respect to branch position in the crown. Using detached shoots, we manipulated leaf water supply and light availability
in order to separate the effects of insufficient hydraulic supply and low irradiance. The intact upper-crown leaves demonstrated
2.0–2.2 times higher (P < 0.001) daily maxima of g
L compared to the lower-crown leaves growing in the shadow of upper branches. Mean soil-to-leaf conductance (G
T) was 1.9 times higher (P < 0.001) for the upper-crown foliage compared to that of the lower crown. The total hydraulic resistance was distributed:
soil to distal shoots—41–51%, 25-cm distal shoots—10–15% and leaves—39–44%. In lower branches, g
L was constrained by both low light availability and limited water supply; in upper branches, only by irradiance. Artificial
reduction of hydraulic constraints raised bulk leaf water potential (Ψ
L) and made g
L less sensitive to changes in both atmospheric and plant factors. Stomatal responses to leaf-to-air vapour pressure difference
(VPD) were significantly modified by leaf water status: high Ψ
L seemingly inverted the g
L versus VPD relationship. Enhanced water supply increased g
L and transpiration rate (E) in the lower-crown foliage, but not in the upper-crown foliage. The results support the idea that leaves in the lower canopy
are hydraulically more constrained than those in the upper canopy. 相似文献
6.
The activity rhythms of marine species may consistently bias demographic evaluation by bottom trawl survey, depending on the time of day. In this study, we examine occurrence data of selected commercial and non-commercial decapod species at different depths (0–800 m) of the western Mediterranean as produced by the Mediterranean international trawl survey (MEDITS) UE Program by sampling during daytime. In order to show how the activity rhythms and types of displacement (pelagic, nektobenthic and endobenthic) of different species can alter the occurrences determined by bottom trawling, and to quantify relative bias, we modeled potential outcomes of a putative nocturnal MEDITS sampling. MEDITS and published data for studies with 24-h hauls were compared in order to obtain a folding correction factor. We found that the temporal bias of sampling is moderate when trawling is performed on the continental slope and more important when it occurs on the continental shelf. The configuration of daytime and nighttime occurrence data by depth was performed using non-metric multidimensional scaling (nMDS). For the daytime configuration, association with irradiance (PAR) was evaluated by fitting occurrence data with a generalized additive model (GAM). Symmetry in species assemblages was found according to depth (inflection point at 200 m depth) as a significant irradiance-dependence distribution pattern of occurrences that took place on the shelf, above 200 m depth. For the night configuration, the inflection point relaxed due to the active displacements of some species, mixing the assemblages reported in daytime data. Results of the present study indicated that a deep knowledge of the autoecology of decapod species as it relates to activity rhythms (including a precise assessment of displacement typology) is of importance in population distribution and biomass evaluation and also influences locally perceived biodiversity. Accordingly, bottom trawl surveys for population assessment should take into account the timing of sampling as a factor potentially biasing obtained abundances. 相似文献
7.
8.
不同土壤水分下金矮生苹果叶片蒸腾速率研究 总被引:6,自引:0,他引:6
林木蒸腾作用与光照强度和土壤水分状况之间存在着密切的关系,蒸腾速率一般随光强的增强和土壤水分的改善而增大。因此,林木在苗期时,当土壤水分不足时,应采取措施避免强光照射,以减轻过度蒸腾失水造成生理伤害,提高成活率和促进苗木生长;有利于限制林木蒸腾失水,提高水分利用效率可考虑的土壤水分范围在10%〈SWC〈15%之间。 相似文献
9.
[目的]为蔬菜大棚的高产栽培提供理论指导。[方法]利用TBQ—DL太阳辐射电流表对蔬菜大棚的辐照度时间和空间变化进行测定和研究。[结果]蔬菜大棚内阴天和晴天辐熙度均呈单峰型曲线,阴天辐照度比晴天弱,阴天辐照度在14:00达到最大值,晴天在12:00达到最大值。阴天和晴天辐照度均随高度的升高呈递增趋势。阴天和晴天大棚不同部位辐照度规律均是:上午东侧〉中侧〉西侧,下午西侧〉中侧〉东侧。[结论]在生产中,尤其是阴天较多的地区,应该更充分利用蔬菜大棚高层的光照资源。 相似文献
10.
The effect of substrate, medium composition, irradiance and ventilation on rooting percentage, and root morphology and functioning with respect to mineral uptake was investigated in jojoba [Simmondsia chinensis (Link) Schneider]. Plantlets grown on Sorbarod plugs embedded in perlite accumulated more biomass and showed better rooting than plantlets grown on Sorbarod plugs embedded in agar. In plants grown on the latter substrate, the addition of sucrose to water or salts media promoted rooting and accumulation of shoot and root biomass. On perlite, rooting was high in all treatments, while root growth was enhanced only by 2% sucrose. Sucrose and irradiance had a positive synergistic effect on plantlet growth. Doubling the irradiance from 58 to 116 μE m−2 s−1 and using high ventilation (22-mm membrane) failed to improve rooting but promoted the ability of the stomata to close, thereby reducing water loss under ambient conditions. High irradiance and ventilation lowered the chlorophyll content, but without impairing biomass accumulation. Plantlets grown under enhanced ventilation and 0.5% sucrose formed fine roots within the cellulose plug and thick roots on the vessel floor. With the 2% sucrose supplementation, the roots were generally thicker, with very few thin roots being formed. 36Cl uptake into plantlets and transport to the leaves decreased in plants exposed to a high sucrose concentration. Acclimatization of jojoba plantlets was improved by enhancing ventilation. 相似文献