小麦光呼吸途径电子流分配的模型研究

为探讨分配到植物光呼吸的光合电子流(J_o)对CO_2浓度(J_o-C_a曲线)的响应规律,以小麦Z39-118为材料,分析了小麦叶片在2%和21%O_2浓度下的光合速率(A_c)和电子传递速率(J)对CO_2浓度的响应曲线。结果表明,光合作用对CO_2浓度的响应新模型(模型I)可很好地拟合小麦的A_c对CO_2浓度响应曲线;同样,基于模型I而构建的J对CO_2的响应模型(模型II),也可很好地拟合小麦在21%和2%O_2条件下的J对CO_2响应曲线。利用模型II分别拟合基于传统公式(J_o=2[J-4(A_c+R_(day))]/3)得到的J_o-C_a曲线(R_(day)为日呼吸速率)及基于光呼吸速率值而计算得到的J_o-C_a曲线,结果显示,两者拟合得到的分配到光呼吸的最大电子传递速率值(分别为86.93和84.17μmol·m~(-2)·s~(-1))与实测值(89.12μmol·m~(-2)·s~(-1))均较为接近(P0.05);但基于前者拟合所得到的饱和CO_2浓度和CO_2为0μmol·mol~(-1)时分配到光呼吸的电子传递速率,均与其对应的测量值之间均存在显著差异(P0.05)。综合分析认为,传统用于计算参与光呼吸途径的光合电子流公式并不能准确地描述J_o对CO_2浓度的响应趋势,本研究构建的新模型可准确地定量研究光呼吸及其电子流分配等问题。     

高产春大豆豆荚与叶片的光合性能研究

以黑农38等6个不同基因型大豆为材料,在鼓粒期对豆荚和叶片的面积在主茎上垂直分布、荚皮和叶片的叶绿素含量、光合速率等生理参数进行了研究.结果表明:高产春大豆在鼓粒期间荚面积为叶片面积的19.83%～35.44%,荚皮叶绿素含量为叶片的5.67%～8.20%,荚的真光合速率为叶片的13.32%～55.98%.黑农38的荚面积占叶面积百分比值、叶片的真光合速率均最高,分别为34.85%、26.4μmolCO_2·m~(-2)·s~(-1);豆荚的真光合速率以吉育67最高,为8.48μmolCO_2·m~(-2)·s~(-1),石豆2号最低,为2.24μmol CO_2·m~(-2)·s~(-1).荚的主要光合生理参数基因型之间的差异大.要进一步提高大豆产量,应发挥鼓粒期荚的光合潜力.     

茶树净光合速率的遗传分析

以亲本“凤凰水仙”(母本)、“福鼎大白茶”(父本)及其杂交后代 F_1为供试材料,测定了秋梢成熟叶片的净光合速率。通过遗传分析,结果表明:茶树叶片净光合速率属于数量性状的遗传,受微效多基因控制,且主要受核基因组控制。根据亲子代方差分析,净光合速率的广义遗传率为0.4154—0.7212,预期遗传进度为1.90—3.04μmol CO_2·m~(-2)·s~(-1);根据 F_1代株系间的方差分析,其广义遗传率为0.5945,遗传变异系数为22.97％,预期遗传进度为2.25μmol CO_2·m~(-2)     

小麦水分利用效率对CO_2浓度响应的模型研究

为了定量研究水分利用效率(water use efficiency, WUE)对CO_2浓度的响应,在植物光合作用对CO_2响应模型的基础上构建了WUE(分为内禀水分利用效率和瞬时水分利用效率,即WUE_i和WUE_(inst))对CO_2(包括大气CO_2浓度和胞间CO_2浓度,即C_a和C_i)的响应模型,并应用新构建的模型对小麦(Triticum aestivum L.)测量数据进行了拟合。结果表明,新构建的模型不仅可以很好地拟合小麦叶片WUE对CO_2浓度的响应曲线(包括WUE_i-C_a、WUE_i-C_i、WUE_(inst)-C_a和WUE_(inst)-C_i曲线),而且还可以直接给出小麦的最大WUE_i和WUE_(inst)以及相对应的饱和C_a和C_i。以小麦WUE_i-C_a和WUE_(inst)-C_a曲线拟合结果为例,得到的最大WUE_i和WUE_(inst)分别为176.29μmol·mol~(-1)和8.65 mol·mmol~(-1),其对应的观测值分别为172.96μmol·mol~(-1)和8.62 mol·mmol~(-1);拟合得到的饱和CO_2浓度分别为1 410.52和1 399.73μmol·mol~(-1),对应的观测值分别为1 294.05和1 332.84μmol·mol~(-1)。拟合值与观测值之间均无显著差异。由此可见,新建模型拟合得到的这些参数与观测值高度相符,可用于植物WUE对未来CO_2增加响应规律研究。     

边际效应对茶树光合特性的影响

为探明边际效应对茶树光合特性的影响,以5份茶树种质为原料,采用GFS-3000便携式光合-荧光测量系统测定各种质在边际效应、常规条件的光合参数。结果表明:叶片净光合速率、蒸腾速率、气孔导度和胞间CO_2浓度分别为2.62～8.30μmol·m~(-2)·S~(-1)、72.04～139.92mmol·m~(-2)·S~(-1)、0.69～1.21mmol·m~(-2)·S~(-1)和300.66～352.63ppm。边际效应整体上降低了茶树净光合速率、气孔导度、蒸腾速率,提高了胞间CO_2浓度。其中,极显著降低了种质L107、L104的净光合速率,显著降低了种质106的净光合速率。综上,边际效应对茶树的净光合速率产生了一定的抑制作用。     

瑞丽山龙眼幼苗光合特性研究

使用Li-6400XT便携式光合仪测定高黎贡山南段2种环境(野外、大棚)下生长的我国特有种植物瑞丽山龙眼幼苗的光合特性,结果表明:(1)2种环境下生长的幼苗净光合速率(PN)日变化出现"双峰"曲线,有"午休"现象,但峰值出现的时刻与大小不同,野外幼苗在10:00、16:00出现高峰值,分别为4.608、2.118μmol/(m~2·s),大棚幼苗在11:00、15:00出现2个高峰值,分别为4.102、3.982μmol/(m~2·s);蒸腾速率(Tr)、气孔导度(Gs)变化趋势与净光合速率变化趋势一致,也有"午休"现象;水分利用率(WUE)无明显变化规律;胞间CO_2浓度(Ci)与净光合速率日变化相反。(2)净光合速率与环境因子偏相关性分析表明,环境因子:光合有效辐射(PAR)、大气CO_2浓度(Ca)、空气温度(Ta)、相对湿度(RH)对幼苗PN值影响均为:PARCaTaRH;(3)两地幼苗光饱和点(LSP)均较高,野外为2 674.995μmol/(m~2·s)、大棚幼苗为2 228.754μmol/(m~2·s),光补偿点(LCP)分别为38.250、8.322μmol/(m~2·s)。     

不同肥料滴灌追施对春小麦光合参数及产量的影响

在滴灌种植模式下,探究不同施肥处理对春小麦光合作用和产量的影响。结果表明:小麦不同生育时期,净光合速率、气孔导度、蒸腾速率和产量差异显著,且以孕穗-开花期小麦旗叶的净光合速率最大(P0.05)。滴灌硅谷肥料(含有机硅0.3%,N、P_5O_2、K_2O均为18%)条件下,孕穗-开花期小麦叶片的净光合速率为12.36μmol/(m~2·s),比滴灌常规肥料(尿素5.95 kg/667 m~2+硫酸钾9 kg/667 m~2+磷酸二铵9.8 kg/667 m~2)的高出2.73μmol/(m~2·s);孕穗-开花期小麦叶片的气孔导度最大,滴灌硅谷肥料条件下的气孔导度为0.92μmol/(m~2·s),较滴灌常规肥料高0.16μmol/(m~2·s);孕穗-开花期春小麦叶片的蒸腾速率最大,滴灌硅谷肥料处理的蒸腾速率为13.65μmol/(m~2·s),比滴灌常规肥料的高出1.23μmol/(m~2·s)。滴灌硅谷肥料处理下,小麦产量较常规肥料处理的高,达到8 653.65 kg/hm~2。     

3个野生大豆与栽培大豆杂交后代品系的光合光响应曲线及模型拟合

以3个野生大豆与栽培大豆杂交后代品系0004、0005和9002为研究对象,并以父本野生大豆为对照,选用4种常用的光响应模型(直角双曲线模型、非直角双曲线模型、修正的直角双曲线模型和指数函数模型)对其进行光响应曲线的拟合,判断这些模型的适宜性,并比较3个杂交后代品系及其父本光合特性的差异。结果表明:这4种模型均可对试验材料进行拟合,决定系数R20.98。但由于直角双曲线模型、非直角双曲线模型和指数函数模型无法求取试验材料最大净光合速率及光饱和点,求得的拟合值不仅与实测值相差较大,也反映不出光抑制现象。而修正的直角双曲线模型则可以克服以上问题,更适用于本试验材料的研究。通过对4个供试材料光合参数的综合比较,认为品系9002具有较好的光合特性,对光的适应能力最强。     

超高产杂交稻的光响应曲线及其模型拟合

以超级杂交一季中稻高产攻关第一、二、三、四期标志性品种两优培九、Y两优1号、Y两优2号、Y两优900及第五期攻关品种超优千号为试验材料,采用4种典型的光合模型对参试品种齐穂期剑叶光合光响应曲线进行了拟合,并对各品种气孔导度和水分利用效率的光响应曲线进行了比较。结果表明,直角双曲线模型、非直角双曲线模型、直角双曲线修正模型及指数函数模型对参试5个品种的光合光响应曲线都可以拟合,决定系数R2均大于0.99;直角双曲线修正模型拟合得到的光合参数与实测值最接近;光能利用率以超优千号和Y两优900最高,剑叶净光合速率(光合能力)以Y两优900最强,光饱和点以Y两优900和Y两优1号最高,暗呼吸速率即光合产物消耗以Y两优900和两优培九最大;气孔导度除Y两优2号随光强增加增长缓慢外,其他4个品种均增长较快,但未出现气孔关闭现象,对强光表现出良好适应性;参试品种水分利用率WUE在光照强度小于800μmol/(m~2·s)时,随光照强度增加而表现为直线升高,当光照强度继续增加,WUE增长缓慢并逐渐趋于稳定,但Y两优900的WUE仍表现出增长态势。因此,Y两优900在光照强度大、日照时数长的地区种植,仍有较大的增产潜力。     

硫化氢对镉胁迫下小麦幼苗的生长及生理指标的影响

为了解硫化氢(H_2S)对Cd~(2+)胁迫下小麦幼苗生长的缓解机理,以小麦品种苏科麦一号为材料,在水培条件下,测定外源H_2S(供体为NaHS溶液)预处理对Cd~(2+)胁迫下(CdCl_2浓度为50μmol·L~(-1))小麦幼苗生长和生理指标的影响。结果显示,外源H_2S预处理显著提高Cd~(2+)胁迫下小麦幼苗的株高、地上部生物量、非蛋白巯基化合物含量、叶片光合色素含量、净光合速率、叶绿素荧光相关指标(PSⅡ的光合性能指数、单位激发态面积吸收的能量、用于还原Q_A和用于电子传递的能量、非光化学淬灭)和根部Cd含量;显著降低小麦叶片中的过氧化物质(丙二醛、过氧化氢和超氧根阴离子)含量及地上部分Cd含量和Cd转运系数。综上所述,外源H_2S预处理可清除Cd~(2+)胁迫小麦幼苗叶片中的活性氧自由基,减少其对光合色素分子的破坏,降低膜脂过氧化程度,保护光合电子传递系统,增加热耗散,提高光合能力,缓解Cd~(2+)对小麦幼苗生长的抑制,以50μmol·L~(-1)的NaHS效果最好。     

沈阳地区亚洲玉米螟及赤眼蜂发生量预测模型研究

2000～2013年田间系统监测沈阳地区亚洲玉米螟和赤眼蜂的发生规律.亚洲玉米螟落卵量、卵孵化量、赤眼蜂寄生量等资料和温度、积温、湿度、雨量、光照等气象资料作为预测因子,采用简单逐步回归、二次多项式逐步回归及多因子互作回归进行拟合,建立不同发生量预测预报模型,并对其进行检验.结果表明,亚洲玉米螟及赤眼蜂发生量与多因子之间存在相关关系,采用预报模型可较为准确地预测出发生量,一代亚洲玉米螟落卵量采用简单逐步回归组建的模型结果可靠;二代亚洲玉米螟卵孵化量与赤眼蜂寄生量采用简单逐步回归和多因子交互组建的模型结果均可靠,玉米螟落卵量采用二次多项式逐步回归模型结果可靠.     

玉米对小斑病T小种抗性的遗传模型分析

用广义遗传模型方法,研究了玉米对小斑病T小种的抗性遗传特性.结果表明:玉米对小斑病T小种的核抗性主要受加性和显性效应控制,以显性效应为主.3个病害指标之间有极显著的正相关,相关性主要归因于加性效应,病斑数和病级之间还有显著的显性遗传相关.另外,根据遗传效应预测值对供试亲本作了评价。     

Adapting the CROPGRO perennial forage model to predict growth of Brachiaria brizantha

Warm-season grasses are economically important for cattle production in tropical regions, and tools to aid in management and research of these forages would be highly beneficial. Crop simulation models synthesize numerous physiological processes and are important research tools for evaluating production of warm-season grasses. This research was conducted to adapt the perennial CROPGRO Forage model to simulate growth of the tropical species palisadegrass [Brachiaria brizantha (A. Rich.) Stapf. cv. Xaraes] and to describe model adaptation for this species. In order to develop the CROPGRO parameters for this species, we began with values and relationships reported in the literature. Some parameters and relationships were calibrated by comparison with observed growth, development, dry matter accumulation and partitioning during a 2-year experiment with Xaraes palisadegrass in Piracicaba, SP, Brazil. Starting with parameters for the bahiagrass (Paspalum notatum Flugge) perennial forage model, dormancy effects had to be minimized, and partitioning to storage tissue/root decreased, and partitioning to leaf and stem increased to provide for more leaf and stem growth and less root. Parameters affecting specific leaf area (SLA) and senescence of plant tissues were improved. After these changes were made to the model, biomass accumulation was better simulated, mean predicted herbage yield per cycle was 3573 kg ha⁻¹, with a RMSE of 538 kg DM ha⁻¹ (D-Stat = 0.838, simulated/observed ratio = 1.028). The results of the adaptation suggest that the CROPGRO model is an efficient tool to integrate physiological aspects of palisadegrass and can be used to simulate growth.     

Observations on the bulking and development of tuber size distribution in maincrop potatoes at Rothamsted in 1964–75

Summary Tuber samples taken at 2-week intervals from plots of cvs King Edward, Majestic and Pentland Crown in 1964–75 showed that the maximum bulking rates ranged from 1 to 5 tonnes/hectare/week. Maximum tuber numbers were usually produced by 11 weeks after planting and thereafter numbers declined. In September, about 70% of the tubers initiated were recovered, and between 24 and 52% of the tubers had reached marketable size (>4 cm). Tuber size distributions developed similarly in all years with all cultivars. During tuber initiation the distributions appeared as one population, and usually between 9 and 11 weeks after planting a second population of larger tubers developed. The population of small tubers later declined although in most years it was still present in September. This development fitted a model based on a mixture of two normal distributions and was determined by five parameters; the proportion of tubers in the small population and the means and standard errors of both populations.     

Simulating the susceptibility of clusters to grape black rot infections depending on their phenological development

In the years 2006–2008, clusters of Vitis vinifera (cv. Riesling) were inoculated with a conidia suspension of Guignardia bidwellii, the causal agent of grape black rot, at weekly intervals from one week before until eight weeks after bloom. Berries’ susceptibility turned out to be strongly linked to the speed of the phenological development in the respective season. In view of this, a degree day-based model simulating the relative susceptibility as a function of the phenological development was established. Infections on inflorescences were already possible prior to bloom. The period of highest susceptibility for direct infection on berries lasted from fruit set to the beginning of bunch closure. Successful infections took place until the end of bunch closure. Ontogenic resistance occurred clearly before veraison. Consequently, control measures should focus on the period between directly prior to bloom and bunch closure. Thus, the time span of black rot control coincides with the period in which vineyards need to be protected against the two major grape pathogens, Erysiphe necator and Plasmopara viticola. Applications of fungicides aimed at powdery and downy mildew control, also effective against G. bidwellii (e.g. strobilurins, triazoles and dithiocarbamates), offer a simultaneous control strategy for these three fungal diseases.     

The feasibility of predicting the number of stems per tuber produced by potato seed stocks from measurements made before planting

Summary The number of stems per seed tuber produced by 17 seed stocks of cv. Record was determined in glasshouse and field experiments to assess the feasibility of predicting the number of stems produced in the field. Multiple regression analysis showed that seed tuber weight alone gave the most satisfactory fit to stems produced in the field, which was not improved by adding terms involving the number of stems produced in the glasshouse. Quadratic relationships between the number of above-ground stems per tuber and tuber weight were most appropriate for each stock, with the fitted curves for individual stocks differing only in the constant term. However, there were significant rank correlation coefficients between the constant terms for relationships between field stems and tuber weight and glasshouse stems and tuber weight, suggesting that in other cultivars and seed stocks a predictive glasshouse test might still be useful.     

大麦籽粒淀粉含量的主基因+多基因遗传模型分析

为了解大麦籽粒淀粉含量的遗传规律,以Noso Nijo×泰兴9425杂种F1花药培养的191个DH系及其亲本为材料,利用植物数量性状主基因+多基因混合遗传模型分析大麦籽粒淀粉含量的遗传规律。结果表明,2010和2012年大麦直链淀粉含量分别符合两对连锁抑制作用主基因模型(B-2-9)和两对连锁互补作用主基因+加性多基因遗传模型(E-2-7),支链淀粉含量分别符合两对抑制作用主基因+加性多基因遗传模型(E-1-9)和两对连锁显性-上位性作用主基因+加性多基因遗传模型(E-2-4),支/直比均符合两对抑制作用主基因模型(B-1-9),总淀粉含量均符合三对等比例加性作用主基因+加性多基因遗传模型(G-2)。     

Resistance toSpongospora subterranea in tuber-bearing and non tuber-bearingSolanum spp.

Summary The incidence of infection withSpongospora subterranea was studied in the non tuber-bearingSolanum brevidens andS. etuberosum and the tuber-bearingS. acaule, S. sucrense andS. tuberosum cvs Olympia and Pito. Shoot cuttings were grown in soil naturally infested withS. subterranea, or the roots were inoculated with a zoospore suspension. Logit models were used to analyse the data. The incidence ofS. subterranea was higher in plants inoculated with zoospore suspension than in those grown in infested soil (odds ratio (OR) 10.65). Ageing the inoculum reduced the incidence of infection in the plants (OR 0.30) without altering the interspecific differences. The ORs of infection (compared to cv. Olympia) were 0.07, 0.29, 0.60 and 2.88 forS. acaule, S. sucrense, S. brevidens andS. etuberosum. OnlyS. acaule was significantly more resistant to infection than cv. Olympia. No infection was detected in cv. Pito.     

Thermal degradation and cyclodepolymerization of poly(ethylene terephthalate-co-isophthalate)s

The thermal degradation of poly(ethylene terephthalate-co-isophthalate)s (PETIs) is investigated by using isothermal thermogravimetric analysis at the temperature range of 280–310°C. The degradation rate of PETIs is increased as the mole ratio of ethylene isophthaloyl (EI) units in PETIs increases. The activation energies for the thermal degradation of poly(ethylene terephthalate), PETI(5/5), and poly(ethylene isophthalate) are 33.4, 16.6, and 8.9 kcal/mole, respectively. The degradation rate of PETIs is influenced by their volatile cyclic oligomer components formed during the polymerization and the thermal degradation. It is simulated by the rotational isomeric state model that the content of cyclic dimer in PETIs, which is the most volatile cyclic oligomer component, increases with the EI units in PETIs.     

Quantifying damage as percentage potato tuber volume lost per peeler stroke

Summary Methods for quantifying external damage and bruising can be inaccurate and result in an index that is difficult to interpret. A new index was derived by taking measurements of peeled slices from cv. Record and developing a mathematical model to predict the percentage volume removed per peeler stroke for a range of potato cultivars. It was found that an average of 1.25% of the tuber volume was removed per peeler stroke. By counting the number of peeler strokes to remove damaged tissue and multiplying by 1.25, an estimate of the percentage tuber volume lost due to bruising or external damage can be obtained. The index can accommodate most types of damage and result in an index that is readily understood.