Photosynthesis and kinetic characteristics of rubisco in Hibiscus cannabinus L

Photosynthetic characteristics in kenaf (Hibiscus cannabinus L.), a C3 plant, were compared with Abelmoschus esculentus (L.) Moench, another member of Malvaceae. Kenaf leaves exhibited significantly higher rate of photosynthesis (40 mg CO2 dm(-2) hr(-1)) which was 24.6 mg dm(-2) hr(-1) in A. esculentus. Rate of photo and dark respiration was similar in both the species. Kenaf leaf photosynthesis had a higher optimum temperature (32 degrees C) than that of A. esculentus (26 degrees C). Photosynthesis in kenaf leaves required higher saturation irradiance (1,600 micromole m(-2) sec(-1)). There was a significant correlation between photosynthetic rate and biomass yield in these species. The primary product of photosynthesis after 5 seconds of 14C-assimilation was 3-PGA in both the species. The kinetic properties of RuBP carboxylase/oxygenase were determined in the leaf extracts. Higher carboxylase activities were recorded with kenaf leaf extracts (245 pmole mg chl(-1) hr(-1)). Km (CO2) for kenaf leaf carboxylase was significantly lower (7.8 microM) than A. esculentus (13.5 microM) and corresponding difference in Vmax values of carboxylase was recorded between the two species. The kinetic characteristics of oxygenase were similar in both the extracts. These results indicated the variation in carboxylase activity and its kinetic characteristics reflected a significant difference in CO2 assimilation in C3 plants.     

Photosynthesis of Ears and Flag Leaves of Wheat and Barley

Immediately after anthesis ears of spring wheat absorbed lessthan 0.5 mg CO₂, per hour in daylight and later evolved CO₂,in the light and in the dark. The rate of apparent photosynthesisof the combined flag-leaf lamina and sheath and peduncle (collectivelycalled flag leaf) of two spring wheat varieties, Atle and JufyI, was 3–4 mg per hour; the rates of the flag leaf andthe ear of two spring barleys, Plumage Archer and Proctor, wereeach about 1 mg per hour. The gas exchange of ears and flag leaves between ear emergenceand maturity accounted for most of the final grain dry weight.The CO₂, fixed by the wheat ear was equivalent to between 17and 30 per cent of the grain weight, but more than this waslost by respiration, so assimilation in the flag leaf was equivalentto 110–20 per cent of the final grain weight. In barley,photosynthesis in the flag leaf and the net CO₂ uptake by theear each provided about half of the carbohydrate in the grain. Barley ears photosynthesized more than wheat ears because oftheir greater surface, and flag leaves of wheat photosynthesizedmore than those of barley because they had more surface anda slightly greater rate of photosynthesis per dm².     

超级高产小麦旗叶荧光动力学研究

探明超级小麦品种的旗叶光合作用与荧光动力学特性,为超级小麦品种选育利用提供理论依据。以超级小麦临麦4号为试验材料,应用CI-301PS型便携式光合作用测定系统和FMS-2便携式荧光测定仪(英国Hansatech公司)在田间试验中测定旗叶光合作用与荧光动力学参数。结果表明,与普通高产对照品种皖麦52和烟农19相比,超级小麦临麦4号的光合作用参数光合速率、光饱和点和CO2饱和点、羧化效率高,光补偿点和CO2补偿点低;光合机构系统工作参数PSII实际的光化学效率(ΦPSII)、光化学猝灭系数(qP)、PSII反应中心的激发能捕获效率(Fv/Fm)、PSⅡ潜在活性Fv/Fo和电子传递速率(ETR)值高,非光化学猝灭系数(NPQ)值低。这表明超级小麦临麦4号的光合机构系统工作能力强和工作效率高,保证旗叶光合作用的高效运行,为子粒灌浆提供充足的能量和碳水化合物。     

施氮量对超高产冬小麦灌浆期旗叶光响应曲线的影响

为冬小麦超高产栽培的氮肥管理提供技术支撑,在大田条件下研究了施氮量对超高产冬小麦灌浆期旗叶光响应曲线的影响.采用开放式气路测定了小麦旗叶的净光合速率、气孔导度、胞间二氧化碳浓度、蒸腾速率等相关指标,并运用"米式方程"对旗叶净光合速率进行了模拟,计算了光响应曲线的特征参数.结果表明,在0～300kg/hm2施氮范围内,随着光照强度的增加,各处理的旗叶净光合速率、气孔导度、蒸腾速率均随之增加,而胞间二氧化碳浓度却随之降低,但是在375kg/hm2施氮水平下旗叶的净光合速率、气孔导度、蒸腾速率的增加和胞间二氧化碳浓度的降低反而低于300kg/hm2施氮水平,表明合理的氮素水平对超高产小麦灌浆期旗叶的光响应曲线有明显的调节作用.在合理的施氮范围内,增施氮肥小麦旗叶在整个灌浆期内的最大净光合速率随之增加.在本试验条件下,超高产麦田的适宜施氮量为300kg/hm2.     

Photosynthetic capacity and dry mass partitioning in dwarf and semi-dwarf wheat (Triticum aestivum L.).

Efficient use of space and high yields are critical for long-term food production aboard the International Space Station. The selection of a full dwarf wheat (less than 30 cm tall) with high photosynthetic and yield potential is a necessary prerequisite for growing wheat in the controlled, volume-limited environments available aboard long-term spaceflight missions. This study evaluated the photosynthetic capacity and carbon partitioning of a full-dwarf wheat cultivar, Super Dwarf, which is routinely used in spaceflight studies aboard U.S. space shuttle and NASA/Mir missions and made comparisons with other dwarf and semi-dwarf wheat cultivars utilized in other ground-based studies in plant space biology. Photosynthetic capacity of the flag leaf in two dwarf (Super Dwarf, BB-19), and three semi-dwarf (Veery-10, Yecora Rojo, IBWSN 199) wheat cultivars (Triticum aestivum L.) was assessed by measuring: net maximum photosynthetic rate, RuBP carboxylation efficiency, chlorophyll concentration and flag leaf area. Dry mass partitioning of carbohydrates to the leaves, sheaths, stems and ear was also assessed. Plants were grown under controlled environmental conditions in three replicate studies: slightly enriched CO2 (370 micromoles mol-1), high photosynthetic photon flux (1000 micromoles m-2 s-1; 58 mol m-2 d-1) for a 16 h photoperiod, 22/15 degrees C day/night temperatures, ample nutrients and water provided by one-half strength Hoagland's nutrient solution (Hoagland and Arnon, 1950). Photosynthetic capacity of the flag leaf was determined at anthesis using net CO2 exchange rate versus internal CO2 concentration curves measured under saturating light (2000 micromoles m-2 s-1) and CO2 (1000 micromoles mol-1). Dwarf wheat cultivars had greater photosynthetic capacities than the taller semi-dwarfs, they averaged 20% higher maximum net photosynthetic rates compared to the taller semi-dwarfs, but these higher rates occurred only at anthesis, had slightly greater carboxylation efficiencies and significantly increased chlorophyll concentrations per unit leaf area. The reduced-height wheat had significantly less dry mass fraction in the stem but greater dry mass partitioned to the ear than the taller semi-dwarfs (Yecora rojo, IBWSN-199). Studies with detached heads confirm that the head is a significant sink in the shorter wheat cultivars.     

不同穗型小麦光能利用和旗叶13C同化物分配特性及对补灌水平的响应

为明确不同穗型小麦冠层光能利用和¹³C同化物分配特性的差异及对补灌水平的响应,以中穗型品种‘青农2号’和‘济麦22’、大穗型品种‘山农23’和‘山农30’为材料,设置3个水分处理:小麦全生育期不灌水(W₀)、节水灌溉(W₁,拔节期和开花期0～40 cm土层土壤相对含水量分别补灌至65%和70%)和充分灌溉(W₂,拔节期和开花期0～40 cm土层土壤相对含水量分别补灌至85%和90%),研究了不同处理对两种穗型小麦冠层光能利用和旗叶¹³C同化物分配特性的影响.结果表明:W₁处理两种穗型小麦品种开花后2、11、20和31 d的叶面积指数、冠层PAR截获率和利用率均显著高于W₀处理,再增加灌水至W₂处理,上述各指标无显著变化.¹³C示踪表明,济麦22和山农23的W₁旗叶¹³C同化物在籽粒中的分配量比W₀分别高159.34和171.1 g·hm^-2,分配比例分别高6.5%和6.5%,与W₂无显著差异;两种穗型品种W₁的籽粒产量亦显著高于W₀,与W₂无显著差异.不同穗型品种比较,节水灌溉条件下中穗型品种在开花后2和11 d、大穗型品种在开花后20和31 d具有较高的冠层光合有效辐射(PAR)截获和利用能力;中穗型品种济麦22旗叶¹³C同化物在籽粒的分配量和分配比例比大穗型品种山农23分别低6.8%和2.7%.     

黑暗诱导衰老对不同年代冬小麦品种旗叶光系统Ⅱ功能的影响

小麦品种的更新换代是小麦产量不断提高的重要因素,阐明小麦品种演替过程中不同生理特性的变化对新品种选育具有重要参考价值.旗叶衰老速率快慢是影响小麦产量水平的关键因素,目前对于不同小麦品种衰老过程中旗叶光系统Ⅱ功能的变化规律尚不清楚.本试验选用1941-2014年间河南地区不同时期种植的31个品种,通过黑暗诱导离体叶片衰老,测定旗叶叶绿素荧光诱导动力学参数、叶绿素相对含量的变化,分析了光系统Ⅱ功能的变化规律.结果表明:品种演替过程中旗叶的叶绿素含量逐渐提高,衰老过程中近代品种叶绿素的降解速率低于较早年代品种;旗叶衰老过程中,近代品种荧光诱导动力学曲线的J点上升幅度小于I点;品种更替过程中光系统Ⅱ最大光化学效率和单位面积有活性反应中心数目逐渐增加,但是近代品种降低速率低于较早年代品种.叶绿素含量的变化与未衰老叶片中F_v/F_m没有显著相关性,但是随着衰老程度增加,相关性逐渐增大,且趋势线斜率逐渐提高;光系统Ⅱ单位面积有活性反应中心数目与品种育成时间呈显著正相关,且随着衰老程度增加,相关程度和趋势线斜率均显著提高.综上,小麦品种演替过程中,旗叶叶绿素含量逐渐升高,降解速率逐渐减缓,光合电子传递过程中Q_A到Q_B电子传递的抗衰老能力得到改善,从而减缓了衰老过程中光系统Ⅱ最大光化学效率和有活性反应中心的衰减速率,同时,叶绿素含量的提高和旗叶光系统Ⅱ抗衰老能力的增强也是品种更替过程中产量逐渐提高的重要因素.     

Photoinhibition and photoprotection in senescent leaves of field-grown wheat plants

Photosynthesis, photosystem II (PSII) photochemistry, photoinhibition and the xanthophyll cycle in the senescent flag leaves of wheat (Triticum aestivum L.) plants grown in the field were investigated. Compared to the non-senescent leaves, photosynthetic capacity was significantly reduced in senescent flag leaves. The light intensity at which photosynthesis was saturated also declined significantly. The light response curves of PSII photochemistry indicate that a down-regulation of PSII photochemistry occurred in senescent leaves in particular at high light. The maximal efficiency of PSII photochemistry in senescent flag leaves decreased slightly when measured at predawn but substantially at midday, suggesting that PSII function was largely maintained and photoinhibition occurred in senescent leaves when exposed to high light. At midday, PSII efficiency, photochemical quenching and the efficiency of excitation capture by open PSII centers decreased considerably, while non-photochemical quenching increased significantly. Moreover, compared with the values at early morning, a greater decrease in CO₂ assimilation rate was observed at midday in senescent leaves than in control leaves. The levels of antheraxanthin and zeaxanthin via the de-epoxidation of violaxanthin increased in senescent flag leaves from predawn to midday. An increase in the xanthophyll cycle pigments relative to chlorophyll was observed in senescent flag leaves. The results suggest that the xanthophyll cycle was activated in senescent leaves due to the decrease in CO₂ assimilation capacity and the light intensity for saturation of photosynthesis and that the enhanced formation of antheraxanthin and zeaxanthin at high light may play an important role in the dissipation of excess light energy and help to protect photosynthetic apparatus from photodamage. Our results suggest that the well-known function of the xanthophyll cycle to safely dissipate excess excitation energy is also important for maintaining photosynthetic function during leaf senescence.     

Changes in rubisco content in relation to saccharides accumulation in wheat leaves during day

Two wheat varieties, T. durum (HD 4502) and T. aestivum (Kalyansona) were examined for photosynthesis rate and contents of sugars and rubisco protein in the flag leaf, at forenoon and afternoon at anthesis stage. A decrease in photosynthesis rate was observed in the afternoon compared to forenoon in both the varieties and was associated with an increase in non-reducing sugars and a decrease in rubisco content in the leaves.     

Effect of assimilate utilization on photosynthetic rate in wheat

Summary Two weeks after anthesis, when the grain is filling rapidly, the rate of photosynthesis by flag leaves of wheat cv. Gabo was between 20 and 30 mg CO₂ dm^-2 leaf surface hour^-1 under the conditions used. About 45% of flag-leaf assimilates were translocated to the ear, and only about 12% to the roots and young shoots.On removing the ear, net photosynthesis by the flag leaves was reduced by about 50% within 3–15 hours, and there was a marked reduction in the outflow of ¹⁴C-labelled assimilates from the flag leaves.Subsequent darkening of all other leaves on plants without ears led to recovery of flag-leaf photosynthesis, as measured by gas analysis and ¹⁴CO₂ fixation, and to increased translocation of assimilates to the roots and young shoots. Minor changes in the rates of dark respiration accompanied these major, reversible changes in photosynthetic rate.After more than a week in continuous, high-intensity light, the rate of photosynthesis by flag leaves of intact plants had fallen considerably, but could be restored again by a period in darkness, or by inhibiting photosynthesis in the ears by spraying them with DCMU. The inhibition of ear photosynthesis increased translocation of labelled assimilates from the flag leaf to the ears, without affecting leaf sugar levels.The application of TIBA to the culm below the ear inhibited auxin movement throught the culm, but had no influence on flag-leaf photosynthesis.These results suggest that, at least in this system, photosynthesis by the flag leaf is regulated directly by the demand for assimilates from the flag leaf and not indirectly through action in the leaf of auxins produced by the sink organs.     

不同耐盐性花生品种对NaCl胁迫的光合和抗逆生理响应特征

以较耐盐花生品种‘花育25’、‘鲁花12’和盐敏感品种‘海花1’、‘花育20’为材料,采用盆栽试验,设置0、1.0、2.0、3.0 g/kg土壤NaCl胁迫浓度梯度,测定其净光合速率、表观量子效率、气孔导度等光合特性,以及抗氧化酶活性和渗透调节物质含量等指标,明确NaCl胁迫条件下不同耐盐性花生品种光合和生理生化特性的适应特征。结果表明：(1)NaCl胁迫明显抑制各品种花生叶片光合作用,净光合速率随盐胁迫浓度的升高呈明显降低的趋势。(2)各品种花生叶片净光合速率均先随光照强度的增强而升高,当光强达到一定数值时趋于平稳;光补偿点和光饱点因品种和盐胁迫浓度差异较大,较高的盐胁迫浓度使叶片光补偿点升高,盐敏感品种的光饱和点降低。(3)盐胁迫条件下,各品种叶片表观量子效率和最大净光合速率均随盐胁迫强度的增加呈显著降低趋势,盐敏感品种利用弱光的能力在低盐胁迫下强于耐盐品种,其最大净光合速率在较高盐胁迫浓度(3.0 g/kg)下明显低于耐盐品种,但两类品种的叶片表观量子效率降幅相近(78.65%~88.00%)。(4)在NaCl胁迫下,耐盐品种叶片自由水含量显著高于盐敏感品种;在2.0～3.0 g/kg NaCl胁迫下,耐盐品种叶片SOD、CAT、POD活性和MDA含量的升降幅度均低于盐敏感品种;耐盐品种在NaCl浓度低于2.0 g/kg时的抗氧化能力明显高于盐敏感品种。研究发现,盐胁迫下花生品种抗盐耐逆的主要生理响应特征是提高光补偿点和最大净光合速率,增强叶片持水能力和物质代谢能力,以及提升抗氧化和渗透调节能力。     

Effect of Nitrogen Fertilizer on Photosynthesis of Several Varieties of Winter Wheat

The rates of gross photosynthesis of the flag leaf and the nextleaf below (second leaf) in crops of winter wheat were estimatedfrom the ¹⁴C uptake of the leaves after exposure to short pulsesof ¹⁴CO₂. The photosynthetic rates of both leaves during thegrain-filling period decreased with increase in nitrogen fertilizerbecause the intensity of photosynthetically active radiationwas less at the surface of the leaves in the dense crops withadditional nitrogen. In addition, the rate of photosynthesisat saturating light intensity was slightly decreased by nitrogen.The effects of nitrogen, in decreasing the rate of photosynthesisper unit area of leaf and in increasing the leaf-area indexof the top two leaves, were such that the photosynthetic productivityper unit area of land of the flag leaf was increased by nitrogenbut the productivity of the second leaf was unaffected. Applying180 kg N ha^–1 increased the productivity of the top twoleaves by a factor of 2.3 but increased grain yield by only1.8. The photosynthetic productivity of the second leaf duringthe grain-filling period was about half that of the flag leaf. There was no difference in photosynthetic rate per unit areaof leaves of Cappelle-Desprez and Maris Huntsman which couldaccount for the larger yield of the latter cultivar. There wasa slight indication that the leaves of the semi-dwarf cultivarsMaris Fundin and Hobbit photosynthesized faster than those ofMaris Huntsman. Triticum aestivum L., winter wheat, photosynthesis, nitrogen fertilizer     

D,L-甘油醛处理引起的小麦叶片表观光合量子效率的降低（英文）

D,L-甘油醛(磷酸核酮糖激酶抑制剂,10mmol/L)处理小麦旗叶1 h可降低叶片净光合速率和表观量子效率.同时,光系统Ⅱ光化学效率(△F/Fm′)、电子传递速率(ETR)和单位叶面积ATP含量均降低,而胞间二氧化碳浓度(Ci)和叶绿素荧光非光化学猝灭(NPQ)增加.这些结果说明,D,L-甘油醛引起的小麦旗叶表观量子效率降低是由于光合碳同化受阻对光合电子传递的反馈抑制.     

冬小麦品种小量播种的产量效应试验

2001-2003年在北京进行了2个年度的冬小麦小量播种秋播试验.2001-2002年,在22.5kg/hm2播量中,参试品种DS 1号的最好产量是5589.0kg/hm2.2002-2003年度,在22.5kg/hm2播量处理中,京411、鲁麦21、晋麦73、DS 1号的产量分别达到8537.7、7403.7、7353.75和6836.25kg/hm2.试验中,旗叶的净光合速率、蒸腾速率、气孔阻力、CO2传导度和叶肉细胞CO2浓度表明植株的生理功能较旺盛.硝酸还原酶和超氧化物歧化酶活性较高,表明植株代谢活动较强.在产量构成因素中,这些品种的单株穗数较多.     

Estimation of yield in wheat from measurements of photosynthesis and translocation in the field

The rate of photosynthesis of ears, flag leaves and second leaves of two varieties of wheat, and the proportion of synthesized carbohydrate translocated from them to the grain, were determined in the field using ¹⁴CO₂. The relationship of rate of photosynthesis to changes in age and in incident radiation was expressed by parameters determining hyperbolic functions. These were combined with empirical equations describing the increase with age in the proportion of photosynthate stored in the grain, to form a mathematical model by which yield was determined from physiological parameters. This model gave estimates of yield in reasonable agreement with measured values.     

Trehalose metabolism in root nodules of the model legume Lotus japonicus in response to salt stress

In wheat ( Triticum aestivum L), the leaves particularly flag leaves have been considered to be the key organs contributing to higher yields, whereas awns have been considered subsidiary organs. Compared with extensive investigations on the assimilation contribution of leaves, the photosynthetic characteristics of awns have not been well studied. In this study, we investigated the ultrastructure of chloroplasts, oxygen evolution, and phosphoenolpyruvate carboxylase [phosphoenolpyruvate carboxylase (PEPCase) EC 4.1.1.31)] activity in both flag leaves and awns during the ontogenesis of wheat. Transmission electron microscope observations showed initial increases in the sizes of grana and the degree of granum stacks from the florescence-emergence stage both in flag leaves and in awns, followed by the breakdown of membrane systems after the milk-development stage. The results of oxygen evolution assays revealed that in both organs, the rate of photosynthesis increased in the first few stages and then decreased, but the decrease occurred much earlier in flag leaves than in awns. A PEPCase activity assay demonstrated that the activity of PEPCase was much higher in awns than in flag leaves throughout ontogeny; the value was particularly high at the late stages of grain filling. Our results suggest that awns play a dominant role in contributing to large grains and a high grain yield in awned wheat cultivars, particularly during the grain-filling stages.     

追施氮肥时期对冬小麦旗叶叶绿素荧光特性的影响

在大田条件下,研究了不同追氮时期对小麦旗叶叶绿素荧光特性、光合速率及籽粒产量的影响.结果表明,拔节期追肥较起身期或挑旗期追肥,改善了小麦旗叶PSⅡ的活性(F_v/F_o)、光化学最大效率(F_v/F_m)、光化学猝灭系数(qP)、实际量子产量(ΦPSⅡ)及光合速率,降低了籽粒灌浆中前期非辐射能量耗散,有利于叶片所吸收的光能较充分地用于光合作用,提高了籽粒灌浆后期非辐射能量的耗散,减缓了叶片光抑制程度和衰老进程.拔节期追肥可显著增加穗粒数和千粒重,提高产量.     

Studies on the Characteristics of Chlorophyll Fluorescence of Winter Wheat Flag Leaves at Different Developing Stages

The parameters of fluorescence induction kinetics and the maximal light-saturated net CO2 assimilation rate ( P sat ) of the flag leaves of four cultivars of winter wheat （Triticum aestivum L.） were compared at three different developing stages for the first time. From the blooming stage to the milky stage, the quantum efficiency of PSⅡ photochemistry ( Fv/Fm ) declined slightly only at the milk stage. The photochemical quenching co-efficient ( qP ), actual quantum yield of photosystem Ⅱ（PSⅡ）electron transport ( Φ PSⅡ) and P sat decreased substantially (>15%), while the non-photochemical quenching co-efficient ( qN ) increased significantly (>100%). There existed a linear correlation between the Φ PSⅡ and the P sat ( r =0.918). The results indicate that with the senescence of the flag leaves of winter wheat the photosynthetic efficiency including that of the energy transport and the CO2 assimilation significantly decreased.     

The Photosynthetic Characteristics of Wheat Ear

The stomata and green cells in wheat ears were observed by electron microscopy, and the photosynthetic activity of the ears was measured with an infra-red gas analyser. 1. The awn, glume, palea, lemma, and axis were photosynthetic organs on the wheat ears. Stomata, however, only existed at the green parts in these organs. The ears which had longer awns and higher content of chlorophyll usually showed relatively high photosynthetic rates. 2. The structure and photochemical activity of the chloroplasts in the awns were similar to those in the leaves. 3. The photosynthetic rate of ears could be promoted by increasing light intensity and CO2 concentration. The CO2 compensation point (110 ppm) and the light compensation point (200μE·m-2 · s-1)of ears were higher than those of leaves. 4. The wheat ears had photoresplration. The CO2-releasing rate of the ears under light could be promoted by high O3 concentration. The CO2 outburst and the oscillation in photosynthesis in the awns could be measured. These results suggested that the photosynthetic pathway in the wheat ears was Cspathway. 5. The highest photosynthetic rate of ears emerged at flowering stage. Thereafter, the photosynthetic activity of the ears fell down as the chlorophyll content declined and the grains were filled up.     

青藏高原春小麦叶片光合作用的光抑制及PSII反应中心光化学效率的恢复分析

在青海省都兰县香日德镇东盛村, 以中国科学院西北高原生物研究所培育的春小麦(Triticum aestivum)品种为材料, 主要采用调制叶绿素荧光分析手段, 研究了抽穗期旗叶光合作用的光抑制现象, 并分析了非光化学猝灭组分的光诱导和非光诱导耗散的量子产量变化。结果表明, 高原春小麦各品种间旗叶光合色素含量和比叶重存在差异; 全晴天3个典型时段准确暗适应20 min后的PSII最大光化学效率(F_v/F_m)的比较分析证实, 高原春小麦存在着光合作用的光抑制现象, F_v/F_m的降低是由于PSII反应中心的可逆失活; 稳态作用光下PSII有效光化学效率(F_v′/F_m′)易受持续强光胁迫的影响, 而PSII实际光化学效率(Φ_PSII)在各春小麦品种间的差异略为明显; 上下午间4个春小麦品种的光化学猝灭系数(q_P)和非光化学猝灭系数(NPQ)呈较一致的变化趋势, 显然q_P和NPQ既属品种的内禀特性, 又与强太阳光胁迫的累积密切相关; 非光化学猝灭组分中光诱导的PSII调节性能量耗散的量子产量(Φ_NPQ)所占比例较大, 下午时分Φ_NPQ的上调反映了高原春小麦对青藏高原持续强光胁迫的驯化适应。