Iron deficiency in citrus limon: effects on photo‐chlorophyllase synthetic pigments and chlorophyllase activity

The photosynthetic pigment composition of chlorotic leaves of Citrus limon L. cv. Verna, grown in the field under iron deficiency conditions was determined. A Fe‐polyflavonoid was used as fertilizer to control iron chloro‐ sis. The photosynthetic pigment content and the chlorophyllase activity were determined at 20 day intervals during the deficiency recovery period and compared to untreated similar material. The corresponding differences among treated and untreated control material were analyzed. Iron application increased the levels of all pigments, but the extent of the increase depended on the pigment affected. The chlorophylls/carotenoids and ß‐carotene/xantophylls ratios were increased as chlorosis diminished. A multivariance analysis was performed with the data obtained which revealed that chlorophyll a and ß‐carotene had the highest correlation coefficient. The chlorophyllase activity did not show significant changes, but it was lower in the treated leaves than in the untreated control leaves during all the sampling cycle.     

Iron‐Binding Properties of TTf,a Salt‐Induced Transferrin from the Alga Dunaliella salina

Abstract

Iron deficiency induces accumulation of a transferrin‐like protein, TTf, in plasma membranes of the halotolerant alga Dunaliella salina. In vivo iron binding and uptake studies provided evidence for the role of TTf in iron acquisition in Dunaliella. In this report, we characterized the iron binding activity of solubilized TTf, purified from plasma membrane vesicles of iron‐starved cells. The characteristics of iron binding to TTf generally resembled those of animal transferrins (Tfs) in an obligatory requirement for bicarbonate as a co‐ligand, specificity for ferric ions and pH dependence of both binding and release. Unlike animal Tfs, Fe binding activity of TTf was stimulated by high NaCl concentrations. The stimulation was not associated with changes in Fe binding affinity. The results unequivocally confirm the role of TTf in Fe binding and uptake in Dunaliella and demonstrate its uniqueness as a membrane‐associated, salt‐stimulated transferrin.     

Effect of gallium on photosynthetic pigments and peroxidase activity of Chlorella pyrenoidosa

Green algae (Chorella pyrenoidosa) were grown in iron‐deficient and normal iron supplied nutrient solution and treated with 1 uM gallium. Treatment with gallium enhanced the growth rate and chlorophyll content of algae cultures. Significant changes were recorded in individual photosynthetic pigment composition of treated cultures. In both iron‐deficient and normal iron supplied cultures, gallium treatment enhanced peroxidase enzyme activity. Partially purified peroxidase showed different kinetic properties in the samples treated with gallium. An iron‐gallium interaction is proposed that affects chlorophyll metabolism and peroxidase activity in green algae.     

外源NO对铜胁迫下番茄光合、生物发光特性及矿质元素吸收的影响

采用营养液培养,研究了外源一氧化氮（NO）供体硝普钠(Sodium nitroprusside, SNP)对50 μmol/L铜（Cu）胁迫下番茄叶片叶绿素含量、光合特性、生物发光强度和矿质营养元素的影响。结果表明,在Cu胁迫下,外施100 μmol/L SNP显著提高番茄叶片叶绿素a、叶绿素b、叶绿素a+b含量、叶绿素a/b比值、净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)和叶片中Cu、Ca、Fe、Zn、Mn以及根系中Cu、K、Fe、Zn的含量; 显著降低叶片超微弱发光强度、荧光强度、磷光强度、胞间CO2浓度(Ci)和根系中Ca的含量。然而,SNP对Cu胁迫下的缓解效应可被NO的清除剂血红蛋白所抑制。在Cu处理液中加入100 μmol/L NO-x（NO的分解产物）或100 μmol/L亚铁氰化钠（SNP的相似物或分解产物）,与Cu胁迫处理差异不显著。表明外源NO可以通过改善Cu胁迫下番茄叶片光合特性,降低超微弱发光、荧光、磷光强度,维持矿质营养元素平衡,缓解Cu胁迫对番茄的抑制作用。     

Photosynthesis and metabolic changes in leaves of rapeseed grown under long‐term sulfate deprivation 1

The effect of prolonged sulfur (S) deficiency on photosynthesis and S‐containing compounds in leaves of rapeseed (Brassica napus L.) plants, grown in nutrient solution, was studied under greenhouse conditions. The rate of photosynthetic activity and stomatal conductance of water and CO₂ in treated plants decreased significantly after 3 months of treatment. The total chlorophyll content decreased after one month of S deprivation, after which it remained constant. The total S. content and both the water‐soluble and non‐protein soluble S fractions in the leaves showed a marked decrease. Whereas, the total protein soluble S remained unaffected during the period of observation. In the treated plants, the content of two major S compounds, e.g., cysteine and glutathione, were as a result of deprivation, although in the control it showed a trend to increase. Sulfur deficiency also decreased appreciably the activity of ATP sulfurylase. After the three‐month period of S deprivation, this enzymatic activity was about four times lower than that in the control plants. The data reported in this paper suggested that plants grown under S deficiency were capable of adjusting their S metabolism to maintain a sufficient protein and glutathione synthesis by lowering their photosynthetic activity.     

Leaf Responses to Reduced Iron Availability in Two Tomato Genotypes: T3238FER (Iron Efficient) and T3238fer (Iron Inefficient)

Abstract

The present work is aimed at evaluating some effects induced by different levels of iron availability in the growth medium for two different tomato (Lycopersicon esculentum Mill.) genotypes, the T3238fer (Tfer), unable to activate mechanisms for iron mobilization and uptake known as “strategy I,” and its correspondent wild‐type T3238FER (TFER). By using different iron concentration in the growth solution, the most suitable iron level to induce phenotypic differences between the two genotypes without being lethal for the mutant was found to be 40 µM Fe‐Na‐EDTA. The analyses were carried out also on plants grown with 80 µM Fe‐Na‐EDTA, an iron concentration at which the two genotypes showed no phenotypic differences. A significant decrease in total leaf iron and chlorophyll content was detected in both genotypes following reduction of iron concentration in the nutrient solution, and was particularly evident in Tfer40, which showed symptoms of chlorosis. The photo‐electron transport rate of the whole chain was significantly affected by growth conditions as well as by genotype, the lowest activity being detected in Tfer40 plants. Chlorophyll a fluorescence analysis revealed an increase in non‐photochemical quenching (q _NP) of Tfer plants grown at both iron concentrations, indicating the activation of photoprotective mechanisms, which, however, were not sufficient to prevent photoinhibition when plants were grown at 40 µM iron, as indicated by significant reduction in PSII photochemistry (F _v/F _m) and photochemical quenching (q _P). The actual quantum yield of PSII (Φ_PSII) and the intrinsic PSII efficiency (Φ_EXC) showed the same behavior of q _P and F _v/F _m ratio. A significant effect of mutation and iron supply on all the pigments was detected, and was particularly evident in the mutant grown at 40 µM iron. A different behavior was shown by the three pigments involved in the xantophyll cycle, violaxanthin being less affected than chlorophylls and the other carotenoids, and zeaxanthin even increasing, due to the xanthophyll cycle activation. In conclusion, the interaction between iron deprivation and fer mutation induced functional alterations to the photosynthetic apparatus. Anyway, as far as concerns the photo‐electron transport activity, the influence of fer mutation seemed to occur independently from iron supply.     

缺钾对水稻不同品种光合和能量耗散的影响

试验测定了钾敏感型(二九丰)和钾钝感型(原丰早)两个水稻品种在缺钾处理41.d后其剑叶的生长、光合光响应曲线、叶绿素荧光参数光响应曲线和暗弛豫动力学曲线。结果表明,缺钾降低了水稻剑叶的光合作用,显著抑制了生长。但是缺钾条件下导致两个水稻品种净光合速率(Pn)下降的主导因子并不相同。在缺钾条件下,原丰早(YFZ)剑叶的Pn随气孔导度(Gs)和胞间CO2浓度(Ci)的下降而下降,但叶绿素荧光参数和叶绿素含量几乎没有变化,说明其Pn下降主要归于气孔的限制。缺钾处理41.d后,二九丰(EJF)在低光强下[500mol/(m2.s)],Pn随Gs和Ci下降,但在更强的光强下,Pn和Gs继续下降,而Ci开始上升,并在1200mol/(m2.s)处超越了对照,说明此时主导因子不单受气孔限制,还受非气孔因子限制;它的光饱和点从1200mol/(m2.s)下降到大约500mol/(m2.s);同时,其荧光参数Fv/Fm、ФPSII、qP和ETR随光强上升而迅速下降,而L(PFD)、E和PP迅速增加,NPQ在1200mol/(m2.s)光强下上升,但是在高光强下却迅速降低,甚至低于对照,而且Fm、Fv/Fm下降,Fo上升,均说明缺钾处理可能使光合机构受到了伤害,发生了光抑制。对非光化学猝灭的分析得到其中间组分qNm可能起了更大的能量耗散作用,部分激发能从PSⅡ转移到PSⅠ,降低了PSⅡ耗散能量的压力。以上结果表明,两品种对钾敏感性不同极可能也与缺钾条件下光保护能力的差异有关。     

Silicon‐induced cadmium resistance in rice (Oryza sativa)

Silicon (Si)‐induced cadmium (Cd) tolerance in rice (Oryza sativa L.) was investigated by analyzing Cd uptake, growth, and physiological parameters. Silicon treatments (0.0, 0.2, or 0.6 mM) were added to 6 d–old seedlings, and Cd treatments (0.0 or 5.0 μM) were added to 20 d–old seedlings. Parameters determined included: maximum net CO₂ assimilation (A_max), stomatal conductance (g_smax), and transpiration (E_max) rates at varying intercellular CO₂ concentrations (C_i). Also measured were chlorophyll fluorescence, growth, and Cd‐uptake parameters. Results showed a Si‐induced inhibition of Cd uptake. However, 0.2 mM or 0.6 mM Si treatment concentrations did not differentially inhibit Cd uptake or differentially alleviate Cd‐induced growth inhibition, despite a significant increase in tissue Si concentration due to 0.6 mM Si treatment compared to 0.2 mM Si treatment. Additionally, photosynthesis and chlorophyll‐fluorescence analysis showed that treatment with Cd significantly inhibited photosynthetic efficiency. Interestingly, the addition of 0.2 mM Si, more so than the addition of 0.6 mM Si, significantly alleviated the inhibitory effects of Cd toxicity on photosynthesis and chlorophyll‐fluorescence parameters. Our results suggest that 0.2 mM Si could be close to an optimum Si‐dose requirement for the alleviation of toxicity symptoms mediated by moderate (5 μM) Cd exposure.     

Cadmium Effects on Sunflower Growth and Photosynthesis

The objective of this work was to evaluate the effects of cadmium (Cd) exposure on sunflower (Helianthus annuus L.) plant growth, chlorophyll content, and fluorescence. Sunflower plants were exposed to different concentrations of Cd (0, 5, 50, and 500 μ M) for 21 d. Growth parameters (organ length, fresh and dry weights) were determined and results compared with two parameters associated with photosynthesis degradation: chlorophyll content and fluorescence (an easy and non-destructive method). Exposure to Cd significantly decreased growth by decreasing shoot and root lengths and their fresh and dry weight. Cadmium also decreased significantly chlorophyll content and fluorescence efficiency in all treatments. Chlorophyll a (chl a) and chl b contents showed a significant correlation with chlorophyll fluorescence (F_v/F_m ratio). The EC₅₀ values showed that the roots' length was the most sensitive endpoint in this study, followed by the roots' and shoots' weight endpoints. Also, chl b showed higher sensitivity to Cd contamination than chl a. These data show that in complement to growth parameters, the use of photosynthetic parameters provides helpful information on plant response to Cd exposure.     

不同生育期灌水处理对小粒型花生光合生理特性的影响

为揭示不同生育时期灌水处理对花生叶片光合生理特性的影响,确定花生水分效率最大时期,采用防雨棚池栽法,对2个小粒型花生品种"花育20号"和"花育27号"分别设置全生育期灌水(CK)、全生育期干旱胁迫处理(T1)、苗期灌水(T2)、花针期灌水(T3)和结荚期灌水(T4)5个处理,对比分析各处理花生叶片光合色素含量和叶绿素荧光动力学参数变化。结果表明,土壤水分状况并未使叶绿素a含量明显变化,但两品种叶绿素a含量升高或降低幅度受不同处理影响。叶片类胡萝卜素含量对土壤水分状况的响应因品种而异,两品种全生育期干旱胁迫处理下到达峰值的时间不一致。两品种结荚期灌水处理均能增加叶绿素b和类胡萝卜素含量。"花育27号"整个生育期内Fv/Fm值高于"花育20号",表明其具有较强的光能转换效率。两个花生品种在结荚期灌水处理均能提高Fv/Fm和Fv/Fo值,提高其光能转换效率,有效避免或减轻了光合机构受损的程度。花针期、结荚期灌水及对照处理能够保持较高的表观光合电子传递速率(ETR)和非光化学淬灭系数(QN)值,保持较高的光合反应总量,但苗期灌水处理对生育后期净光合速率没有促进作用。各生育期不同灌水处理中净光合速率(Pn)和气孔导度(Gs)下降的同时,胞间CO2浓度(Ci)亦下降,表明气孔限制是土壤水分不足状况下花生光合速率下降的主要原因。总体而言,花针期和结荚期灌水处理能提高花生叶片的光合能力,表明花生开花以后进行灌水处理是经济有效的灌水方式。     

KClO3诱导东魁杨梅成花的生理效应

研究不同KClO3浓度对6年生东魁杨梅成花过程生理生化的影响,结果表明:喷施KClO3后东魁杨梅叶片细胞受到伤害处于胁迫状态,丙二醛含量和电解质渗漏率显著增加.KClO3浓度低于1 500 mg·L-1时,叶绿素a、叶绿素b以及总叶绿素含量均显著增加,SOD、POD和CAT活性显著提高,导致叶片光合能力显著上升;生理分化期叶片蛋白质含量明显上升,可溶性糖含量降低;而形态分化期蛋白质含量下降,可溶性糖含量显著上升,可溶性糖/蛋白质比值显著增加,从而促进东魁杨梅的花芽分化.KClO3浓度高于1 500 mg·L-1时,叶绿素a、叶绿素b、总叶绿素和类胡萝卜素含量均降低;SOD、POD和CAT活性降低;导致叶片光合能力、可溶性糖含量以及可溶性糖/蛋白质比值显著下降,从而抑制东魁杨梅的花芽分化.结论是喷施1 000～ 1 500 mg·L-1 KClO3可显著提高东魁杨梅的成花率.     

The Effect of High Concentration of Negative Ions in the Air on the Chlorophyll Content in Plant Leaves

This research was done on the effectof high concentration of negative ions in the air onchlorophyll contents and photosynthetic efficiency in leavesof Zea mays L. In vivo reflectance and chlorophyllfluorescence were measured in intact maize leaves before andafter exposing to the high concentration of negative ions inthe air. Reflectance, yield of chlorophyll fluorescence, redshift in chlorophyll fluorescence and blue shift inreflectance are observed in exposed species. These resultsindicate that high concentrations of negative ions inair cause significant change in: a) chlorophyll content andb) photosynthetic efficiency.     

Photosynthesis,Chlorophylls, and SPAD Readings in Coffee Leaves in Relation to Nitrogen Supply

The export of nitrogen (N) from senescent plant parts is important for the efficient use of this macronutrient. The objective of this study was to establish correlations among the photosynthetic pigment content, total N, and the photosynthetic variables with the SPAD‐502 readings in Coffea arabica leaves. Correlations were established among the chlorophyll content, N content, and chlorophyll a and b with SPAD‐502 readings taken on coffee leaves at different months. The results show that all variables decreased with time. However, correlation increased linearly with N doses. Total chlorophyll presented a direct linear correlation with readings of the portable chlorophyll meter. The SPAD readings have shown to be a good tool to diagnose the integrity of the photosynthetic system in coffee leaves. Thus, the portable chlorophyll SPAD‐502 instrument can be used to evaluate the N status and can also help to evaluate the photosynthetic process in coffee plants.     

Interactive effects of salinity and iron deficiency on different rice genotypes

Salinity adversely affects plant growth, photosynthesis, and availability of nutrients including iron. Rice (Oryza sativa L.) is susceptible to soil salinity and highly prone to iron (Fe) deficiency due to lower release of Fe‐chelating compounds under saline conditions. In order to investigate the effects of salinity and low iron supply on growth, photosynthesis, and ionic composition of five rice genotypes (KS‐282, Basmati Pak, Shaheen Basmati, KSK‐434 and 99417), a solution culture experiment was conducted with four treatments (control, 50 mM NaCl, Fe‐deficient, and 50 mM NaCl + Fe‐deficient). Salinity and Fe deficiency reduced shoot and root growth, photosynthetic and transpiration rates, chlorophyll concentration, and stomatal conductance. The reduction in all these parameters was more in the interactive treatment of salinity and low Fe supply. Moreover, a significant increase in shoot and root Na⁺ with corresponding decrease in K⁺ and Fe concentrations was also observed in the combined salinity and Fe‐deficiency treatment. Among the tested genotypes, Basmati Pak was the most sensitive genotype both under salt stress and Fe deficiency. The genotype KS‐282 performed better than other genotypes under salinity stress alone, whereas Shaheen Basmati was the best genotype under Fe deficiency in terms of all the studied parameters.     

Evaluation of nutrient deficiencies in wheat seedlings by chlorophyll fluorescence

Chlorophyll fluorescence of plants is altered by conditions that affect photosynthesis and has proven useful in screening for resistance to environmental stresses. This study evaluated chlorophyll fluorescence for assessing the physiological impact of nutrient deficiencies and for diagnosing deficiencies of specific nutrients. Major nutrient (N,P,K) deficiency‐induced changes in chlorophyll fluorescence were determined in ‘Len’ hard red spring wheat (Triticum aestivum L.). Seedlings were grown in media containing 0, 1, 10, 50, or 100% of N and 0, 1, 10, or 100% of P and K in full‐strength Hoagland solution in a growth chamber for 22 d. Changes in initial (Fo), maximum (Fm), and variable (Fv) chlorophyll fluorescence of leaves and weight, height, and N, P, K, and Mg concentrations of shoots were measured. All chlorophyll fluorescence parameters declined significantly as N, P, and K concentrations declined, but thylakoid membrane efficiency (Fv/Fm and Fm/Fo) was stable at all nutrient levels. Relative units of Fo, Fm, and Fv were usually significantly and positively correlated with growth and. N,P,K, and Mg concentrations of shoots. Chlorophyll fluorescence may be a useful measure of severity of nutrient deficiencies. Use of chlorophyll fluorescence for diagnosing specific deficiencies may not be feasible, however, because of the similar effects of different nutrients.     

RESPONSE OF SALT STRESSED STRAWBERRY PLANTS TO FOLIAR SALICYLIC ACID PRE-TREATMENTS

Salinity has deleterious effects on plant growth and development through membrane stability, photosynthetic activity, protein content, and ionic composition; however, salicylic acid (SA) could restore these properties in plants. The objective of this study was to determine the ameliorative effects of SA as foliar pre-treatments on membrane permeability, proline and protein contents, chlorophyll a, b and total chlorophyll and ionic composition of strawberry cv. ‘Camarosa’ under saline conditions. Membrane permeability and proline content significantly increased and protein and chlorophyll contents significantly decreased by 6 mS cm^?1 application without SA treatment compared with the control (2 mS cm^?1) treatment. Membrane permeability decreased from 6.9 in 0 mM SA treatment to 5.2 by application of 1.0 mM SA under saline conditions and same to the control (5.2). Compared with 0 mM SA treatment, the average increases of proline and protein contents were 66.7% in 0.25 mM SA treatment and 62.2% in 0.1 mM SA treatment in 6 mS cm^?1 level, respectively. Chlorophyll b and total chlorophyll significantly increased by 0.25 mM SA treatments under saline conditions. The lowest and the highest chlorophyll b and total chlorophyll were obtained from 0 mM SA treatment (19.6 and 44.5 mg L^?1) and 0.25 mM SA treatment (28.6 and 52.9 mg L^?1) in 6 mS cm^?1 salinity level. Ionic compositions of leaves were significantly affected by salinity and SA treatments. Nitrogen in 1.0 mM SA treatment and P contents of leaves in 0.1 mM SA treatment significantly increased but Na and Cl contents of leaves significantly decreased by SA treatments in 6 mS cm^?1 salinity level. The results of this study were clearly indicated that the SA application on strawberry plants could ameliorate the deleterious effect of salt stress on membrane permeability, proline, protein, and chlorophyll contents. Therefore, SA treatment could offer an economic and simple application to salinity stress.     

Characterization of the tolerance to excess manganese in four maize varieties

Abstract

Manganese (Mn) is an essential micronutrient in all organisms, but may become toxic when present in excess. Four maize (Zea mays L.) varieties, Kneja 605, Kneja 434, Kneja 509 and Kneja 537, were studied with respect to their responses to excess Mn in hydroponic solution. In the varieties Kneja 605, Kneja 509 and Kneja 537, increasing Mn concentrations in the nutrient solution negatively affected biomass accumulation, photosynthetic rate, transpiration, stomatal conductance and chlorophyll content. In addition, these varieties showed increased electrolyte leakage and lipid peroxidation (malondialdehyde [MDA] content). Increased Mn leaf concentrations, higher contents of chlorophyll a and chlorophyll b, higher photosynthetic rate and transpiration, lower concentrations of MDA and insignificant changes in the electrolyte leakage in the leaves were found in var. Kneja 434 compared with the other maize varieties studied. This variety appeared to possess a stronger ability to cope with Mn phytotoxicity, suggesting high potential for Mn detoxification and var. Kneja 434 could be a good candidate for improving maize productivity on acid soils under non-tropical conditions.     

Effects of the Frequency of Iron Chelate Supply by Fertigation on Iron Chlorosis in Citrus

Abstract

A field experiment was carried out in a drip‐irrigated orchard of Clementine (Citrus clementina Ort. ex. Tan) grafted on Troyer citrange (C. sinensis × Poncirus trifoliata) rootstock located in the Valencian Citrus area (Spain). The trees received a single iron (Fe) EDDHA (ethylene diamine diorthohydroxyphenyl acetate) rate (3 g Fe tree^?1) supplied in different application frequencies from April to September (8‐, 4‐, 2‐, or 1‐week intervals). Leaf chlorophyll (Chl) concentrations were estimated every month by using an SPAD‐502 meter. The foliar contents of Fe were also evaluated with time. Mineral composition of leaves, total Chl concentration, yield, and fruit quality were also evaluated at the end of the assay. SPAD readings, Chl, N, K, Mg, Fe, and Mn concentration in leaves increased as a result of Fe application. The concentration of Zn, however, significantly decreased in comparison to the control trees. Iron treatment increased yield and some of the fruit quality parameters, like total juice, sugar, and acid contents. Iron application frequency had not a consistent effect on the concentrations of macro and micronutrients in leaves, yield, and fruit quality. The highest values of SPAD readings and the leaf Chl content were obtained when Fe was applied at 4‐week intervals along the year. These results suggest that soil Fe‐EDDHA application with a moderate frequency could be recommended to the Citrus farmers in the area for a more rational Fe application along the growth cycle in Citrus orchards.     

一氧化氮改善铁胁迫玉米光合组织结构及其活性

一氧化氮(NO)影响植物生长发育过程及其机制是近年来的研究热点,在植物生长发育的多个层面起着重要的作用。以硝普钠(SNP)为一氧化氮发生剂,液体培养20.d龄的玉米幼苗叶片为实验材料进行研究,结果表明,NO可完全逆转玉米幼苗由缺铁引起的脉间失绿现象,极显著地提高叶片叶绿素含量。电镜观察结果证实,NO促进了玉米叶片叶肉细胞和维管束鞘细胞中叶绿体的发育,叶绿体数量增多且体积增大,基质片层和基粒数量明显增多且结构完好。同时,NO促进了缺铁玉米类囊体膜色素蛋白复合体的装配并显著提高了光合链的电子传递速率,使叶片光合活性得到极显著增加。     

蓝、紫粒小麦光合特性的研究

以西南地区的白粒小麦品种("绵阳26"和"川麦107")为对照,对新育成的蓝、紫粒小麦品种(系)在不同发育时期的光合色素含量、净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和胞间CO2浓度(Ci)等光合特性进行比较分析。结果表明,蓝、紫粒小麦叶片叶绿素a、叶绿素b和总叶绿素含量和对照的白粒小麦一样,均随孕穗期、抽穗期、开花期、灌浆期和成熟期的发育进程而下降,在孕穗期含量最高,成熟期含量最低;蓝粒小麦的叶绿素a、叶绿素b和总叶绿素含量在各发育时期均最低;白粒小麦的叶绿素a和总叶绿素含量在除孕穗期外的各发育时期最高,成熟期的叶绿素b含量也最高。白粒小麦叶片中类胡萝卜素含量随发育进程一直下降,直至成熟,而紫粒和蓝粒小麦在开花期前逐渐下降,但开花期后又逐渐升高,成熟时达到最大值;灌浆期和成熟期类胡萝卜素含量最高的是蓝粒小麦,其次是紫粒小麦,白粒小麦最低。蓝、紫粒小麦和白粒小麦的净光合速率均随发育进程呈先升后降的变化趋势,开花期净光合速率最大;白粒小麦在除灌浆期外的其他生育期净光合速率最大,蓝粒小麦在开花期后净光合速率是最低的。蓝、紫粒小麦和白粒小麦的气孔导度和蒸腾强度均随发育进程呈单峰曲线变化,峰值出现在灌浆期。白粒小麦的气孔限制值在孕穗期到开花期低于紫粒和蓝粒小麦,而开花期后则高于紫粒和蓝粒小麦。新近育成的几个蓝、紫粒小麦的光合能力低于白粒小麦。