叶片氮浓度对温室黄瓜花后叶片最大总光合速率影响的模拟

光合作用是作物产量和品质形成的基础,直接受到叶片含氮量的影响。该文通过不同定植期不同氮素处理试验,建立了不同光温条件下温室黄瓜叶片适宜氮浓度的求算方程,并定量分析了不同光温条件下黄瓜叶片最大总光合速率与叶片氮浓度的关系。在此基础上,进一步建立了适合不同光温条件的温室黄瓜花后叶片最大总光合速率与叶片氮浓度关系的通用模型,并用与建模相独立的试验数据对模型进行了检验。结果表明,建立的模型能较好地预测不同定植期黄瓜叶片氮浓度对叶片最大总光合速率的影响。模型对温室黄瓜叶片最大总光合速率的预测结果与实测结果之间基于1︰1直线的决定系数和均方根差分别为0.83和1.56μmol·m-2·s-1。建立的模型可以为温室黄瓜周年生产的氮素精确管理提供理论依据与决策支持。

氮、磷、钾配施对油葵杂交种群体总光合势的影响

采用"3414"最优饱和设计方案,于2010年在辽宁省农科院试验田以氮(N)、磷(P2O5)、钾(K2O)肥为研究因素进行田间试验。探讨氮、磷、钾3个因素对油葵杂交种F60总光合势的影响。经分析发现,施入不同配比的氮、磷、钾肥,能显著提高油葵群体的总光合势。

总光合作用与净光合作用辨析

在光合作用与呼吸作用的教学中,由于二者之间存在的联系,使得该部分内容的综合性较强,相关计算是难点。为此,借助呼吸作用,辨析总光合作用与净光合作用的差异,并结合具体的案例进行解析,以期为广大师生提供借鉴。

日本霞浦湖浮叶植物Traqa natans.L群落的光合作用与第一性生产量的季节变化

浮叶植物的物质生产有一定特点,尽管有些叶子挺出水面或潜入水中,但是大多数漂浮植物都贴水面水平分布。叶子近轴面暴露在空气中,而远轴面与水接触。功能气孔分布在近轴面(A,B.Sinha与R.Sahal,1974;V.Kaul,1971)。气体交换多半发生在空气之中(生岛,1970),其光合效率可与陆生植物相比(生岛,1970;A.B.S(?)eha与R.Sahal,1974;土谷与岩城,1979)。同挺水植物和沉水植物相比,浮叶植物光合特点和光合生产力的研究是不充分的。有人通过气体交换和数学模型估测了浮叶植物Nymphoids indica O.Kuntze(生岛,1970)和Trapa natans L。(土谷与岩城,1979)的日净第一性生产力。但是。

氮、磷、钾配施对食葵杂交种群体生理参数的影响

采用"3414"最优饱和设计方案,于2014年在辽宁省农业科学院以氮(N)、磷(P2O5)、钾(K2O)肥为探讨因子进行田间试验。探讨氮、磷、钾3因素与食葵杂交种丰葵杂一号生育进程、叶面积指数和总光合势的影响。分析发现,施入不同配比的氮、磷、钾肥,均可不同程度延长食葵营养生长、生殖生长和生育期;不同配比的氮、磷、钾肥对食葵叶片的形成与功能维持都有促进作用,各施肥处理出苗后叶面积增速较快,最大叶面积指数到达的时间较晚,下降的速度慢;增施氮、磷、钾肥能提高食葵的全生育期总光合势,超量施氮仍能大幅度提高总光合势,但超量施入磷、钾肥引起的增量却有限;氮、磷、钾肥在食葵生长的各时期对干物质积累均有明显的促进作用;氮、磷、钾配施对食葵的各器官比例的影响除经济系数的较大外,其余影响均较小。

氮、磷、钾配施对油葵杂交种群体生理参数的影响

采用"3414"最优饱和设计方案,以氮(N)、磷(P2O5)、钾(K2O)肥为探讨因子进行田间试验。探讨氮、磷、钾3因素与油葵杂交种F60生育进程、叶面积指数和总光合势的影响。分析发现,施入不同配比的氮、磷、钾肥,均可不同程度延长油葵营养生长、生殖生长和生育期;施入不同配比的氮、磷、钾肥,均可显著提高油葵的叶面积指数,维持叶片较长时间的功能期,分别施氮、磷和钾能使油葵提前12 d、10 d和7 d达到最大叶面积指数,且最大叶面积指数均高于无氮、磷或钾的处理,下降的速度也较慢;施入不同配比的氮、磷、钾肥,能显著提高油葵群体的总光合势,最高可达对照的1.21倍。

杂交小麦大幅度提高产量优势新途径

与常规品种比较,杂种小麦总光合生物产量优势明显,但输入到籽粒中的光合产物比例较小,或产量结构不够理想,其产量优势不突出。因此,杂种小麦要突破生产应用关仍需寻找突破口。笔者根据多年从事常规小麦育种研究结果,提出杂种小麦、化学杂种小麦大幅度提高产量优势的新途径。

植树造林能够阻止大气层CO_2 增多吗?

植树造林已被广泛提出做为防止、减少或延迟由燃烧矿物燃料导致的大气层 CO_2浓度激增的手段。本文考察并分析了生物量中的碳贮存量,探讨了可用于造林的土地面积,正在开发中的人工林的碳贮存率,以及采伐产物的结局。笔者断定,尽管将成熟林转换成人工幼林是一种失策,但地球历史上的森林占地面积之大以及人工幼林可能有足够高的碳贮存率,因此在宜林荒地上造林能够从大气层中消除大量的碳(≥1Pg^(?)/年)。但是,快速的碳净贮存只是一种短期生命现象,并且大部分人工林采伐物不可能长期保存。因此以贮碳为目的的新造人工林对大气层 CO_2的积累至多只起短期延迟作用.从生物量中获取能源为目的的人工林才会对减少 CO_2的积累做出长久的贡献——只要人工林能够成为取代矿物燃料的生物能源。

光合作用“总”与“净”的辨析

怎样区别光合作用中的“总”与“净”，本文从5个方面对其进行了比较，并举例加以分析。

Responses of Photosynthetic Pigment, Phenol and Total Saponin Contents of Panax notoginseng to Supplemental UV-B under Field Conditions

[Objective] The aim of this study was to investigate the content changes and their correlations of the photosynthetic pigment,phenols,including total phenols,total flavonoids and anthocyanins,and total saponins of the one-year-old P.notoginseng plants under supplemental UV-B stress in fields.[Method] The one-year-old plants were irradiated by UV-B in field for 1 min per day,and the plants under the UV-B lamp were regarded as a circle center,achieving an annular leaf-sampling.The photosynthetic pigment,phenols and total saponins of the leaves were determined spectrophotometrically.[Result] With the increase of sampling radius,the supplemental UV-B intensity decreased significantly,the contents of chlorophyll （Chl） a,Chl b,Chl （a＋b）,carotenoid （Car） and total photosynthetic pigment （Chl＋Car） of the leaves increased extremely significantly,the Chl a/b and total phenol content （TPC） decreased extremely significantly,but the Chl （a＋b）/Car changes were not significant.The contents of total flavonoids,anthocyanins and saponins all increased due to the increasing of UV-B,displaying dose effects.The UV-B intensity was positively correlated with the Chl a/b,and negatively with the Chl a,Chl b,Chl （a＋ b）,Car and （Chl＋Car） contents; and the two of TPC,total flavonoid content （TFC）,total anthocyanin content （TAC） and total saponin content （TSC） were positively correlated,all reaching extremely significant level.The UV-B intensity was positively and significantly correlated with the total flavonoid content （TFC）,negatively and significantly with the Chl （a＋b）/Car,and positively and insignificantly with the TPC,TAC and TSC.[Conclusion] For one-year-old plants of P.notoginseng,UV-B can decrease the contents of the Chl a,Chl b,Chl （a＋b）,Car and （Chl＋Car） and increase the Chl a/b and TPC,and,furthermore,induce the increases of the TFC,TAC and TSC in a dose-dependent manner.However,UV-B can hardly change the Chl （a＋b）/Car.The supplemental UV-B of well-suited dose might be one of the effective measures to improve the TSC of P.notoginseng.

A comparative analysis of fatty acid composition and fucoxanthin content in six Phaeodactylum tricornutum strains from diff erent origins

Phaeodactylum tricornutum is a potential livestock for the combined production of eicosapentaenoic acid(EPA) and fucoxanthin. In this study, six marine diatom strains identified as P. tricornutum were cultured and their total lipid, fatty acid composition and major photosynthetic pigments determined. It was found that the cell dry weight concentration and mean growth rate ranged between 0.24–0.36 g/L and 0.31–0.33/d, respectively. Among the strains, SCSIO771 presented the highest total lipid content, followed by SCSIO828, and the prominent fatty acids in all strains were C16:0, C16:1, C18:1, and C20:5(EPA). Polyunsaturated fatty acids, including C16:2, C18:2, and EPA, comprised a significant proportion of the total fatty acids. EPA was markedly high in all strains, with the highest in SCSIO828 at 25.65% of total fatty acids. Fucoxanthin was the most abundant pigment in all strains, with the highest in SCSIO828 as well, at 5.50 mg/g. The collective results suggested that strain SCSIO828 could be considered a good candidate for the concurrent production of EPA and fucoxanthin.

氮素添加对内蒙古草甸草原生态系统CO_2交换的影响

氮沉降增加将影响草原生态系统固碳,但如何影响草原生态系统CO_2交换目前为止还没有定论。同时,不同类型和剂量氮素对生态系统CO_2交换影响的差异也不明确。选取内蒙古额尔古纳草甸草原,开展了不同类型氮肥和不同剂量氮素添加条件下生态系统CO_2交换的野外测定。实验设置尿素和缓释尿素2种类型氮肥各5个剂量水平(0、5.0、10.0、20.0和50.0g N·m^(–2)·a^(–1))。结果显示,生长季初期及中期降雨量低时,氮素添加抑制生态系统CO_2交换;而生长季末期降雨量较高时促进生态系统CO_2交换。随着氮素添加水平的提高,NEE和GEP均显著增加,当氮素添加量达到10 g N·m^(–2)·a^(–1)时,NEE和GEP的响应趋于饱和。2种氮肥(尿素和缓释尿素)仅在施氮量为5 g N·m^(–2)·a^(–1)时,缓释尿素对生态系统CO_2交换的促进作用显著大于尿素,在其它添加剂量时差异不显著。研究结果表明:氮素是该草甸草原生态系统的重要限制因子,但氮沉降增加对生态系统CO_2交换的影响强烈地受降雨量与降雨季节分配的限制,不同氮肥(尿素和缓释尿素)对生态系统CO_2交换作用存在差异。

盘点以油菜为背景的生物学试题

油菜不仅是我国广泛种植的油料经济作物,而且近年来又成为各地旅游观赏作物,并常常成为命题背景的材料。一、近年高考涉及的试题举例1.考查细胞的结构、分子组成、物质运输及能量供应和利用例1(2015·高考山东卷)油菜果实发育所需的有机物主要来源于果皮的光合作用。

建构水池平衡模型 巧解稳态调节试题

受多种因素的影响,生物体内复杂的生理过程会表现出种类、程度各不相同的变化,这些变化往往又在一定范围内动态进行,即为动态平衡。生理过程的动态平衡分析是生命过程分析的基本内容和方法,也是解析相关高考试题的基本出发点。看似纷繁复杂的生理过程,其本质常常蕴含着一个共同平衡的规律,参照日常生活中的水池平衡原理,可以对生理过程建构水池平衡模型,以求准确理解和分析生理过程的动态平衡。

以高考题为例分析解题方略

高考题是专家经过精心研究编写出来的,具有典型性,通过对高考题的训练和分析,有助于提高同学们的解题能力。例一:【2011年新课标全国卷,29】在光照等适宜条件下,将培养在CO2浓度为1%环境中的某植物迅速转移到CO2浓度为0.003%的环境中,其叶暗反应中C3和C5化合物微摩尔浓度的变化趋势如下图。回答问题:

“光”与“呼”的交融

光合作用和细胞呼吸是高中生物的核心考点光合作用和细胞呼吸是高中生物的核心考点,而绿色植物的活细胞每时每刻都在进行细胞呼吸时每刻都在进行细胞呼吸,在有光照时还要进行光合作用。因此,纵观近几年高考试题几年高考试题,发现有关绿色植物＂净光合作用＂的问题倍受青睐。而这些试题解题的突破口首要就是要明确判断净光合作用与总光合作用试题解题的突破口首要就是要明确判断净光合作用与总光合作用。

Remote Sensing Indices to Measure the Seasonal Dynamics of Photosynthesis in a Southern China Subtropical Evergreen Forest

The accurate measurement of the dynamics of photosynthesis in China’s subtropical evergreen forest ecosystems is an important contribution to carbon(C) sink estimates in global terrestrial ecosystems and their responses to climate change. Eddy covariance has historically been the only direct method to assess C flux of whole ecosystems with high temporal resolution, but it suffers from limited spatial resolution. During the last decade, continuous global monitoring of plant primary productivity from spectroradiometer sensors on flux towers and satellites has extended the temporal and spatial coverage of C flux observations. In this study, we evaluated the performance of two physiological remote sensing indices, fluorescence reflectance index(FRI) and photochemical reflectance index(PRI), to measure the seasonal variations of photosynthesis in a subtropical evergreen forest ecosystem using continuous canopy spectral and flux measurements in the Dinghushan Nature Reserve in southern China.The more commonly used NDVI has been shown to be saturated and mainly affected by illumination(R^2=0.88, p <0.001), but FRI and PRI could better track the seasonal dynamics of plant photosynthetic functioning by comparison and are less affected by illumination(R^2=0.13 and R^2=0.51, respectively) at the seasonal scale. FRI correlated better with daily gross primary production(GPP) in the morning hours than in the afternoon hours, in contrast to PRI which correlated better with light-use efficiency(LUE) in the afternoon hours. Both FRI and PRI could show greater correlations with GPP and LUE respectively in the senescence season than in the recovery-growth season. When incident PAR was taken into account, the relationship between GPP and FRI was improved and the correlation coefficient increased from 0.22 to 0.69(p < 0.001). The strength of the correlation increased significantly in the senescence season(R^2=0.79, p < 0.001). Our results demonstrate the application of FRI and PRI as physiological indices for the accurate measurement of the seasonal dynamics of plant community photosynthesis in a subtropical evergreen forest, and suggest these indices may be applied to carbon cycle models to improve the estimation of regional carbon budgets.

Estimation of Endocarpon pusillum Hedwig carbon budget in the Tengger Desert based on its photosynthetic rate

This study investigated the photosynthetic rate of the lichen Endocarpon pusillum at the Chinese Academy of Sciences Shapotou Desert Research Station and estimated its annual contribution to the carbon budget in the ecosystem. The software SigmaPlot 10.0 with "Macro-Area below curves" was used to calculate the carbon fixation capacity of the lichen. The total carbon budget (ΣC) of the lichen was obtained by subtracting the respiratory carbon loss (ΣDR) from the photosynthetic carbon gain (ΣNP). Because water from precipitation plays an important role in photosynthesis in this ecosystem, the annual carbon budget of E. pusillum at the station was estimated based on the three-year average precipitation data from 2009 to 2011. Our results indicate that the lichen fixes 14.6 g Cm-2 annually. The results suggest that artificial inoculation of the crust lichen in the Tengger Desert could not only help reduce the sand and dust storms but also offer a significant carbon sink, fixing a total of 438000 t of carbon over the 30000 km2 of the Tengger Desert. The carbon sink could potentially help mitigate the atmospheric greenhouse effect. Our study suggests that the carpet-like lichen E. pusillum is an excellent candidate for "Bio-carpet Engineering" of arid and semi-arid regions.