Variation Of Net Photosynthetic Rate Research Articles

Distinguishing High Daytime From Nighttime Temperature Effects During Early Vegetative Growth in Cotton

ABSTRACTHigh‐temperature limits early season vegetative growth of cotton, and the physiological response of cotton (Gossypium hirsutum L.) to high daytime or nighttime temperature needs to be explored. The objectives of the current study were to determine (1) plant growth response, (2) physiological contributors to variation in biomass production and (3) mechanisms driving variation in net photosynthetic rate (AN) in response to different combinations of high daytime and nighttime temperatures. Beginning at planting, cotton was exposed to four different growth temperature regimes: (1) optimum (30/20°C day/night), (2) high nighttime (30/30°C), (3) high daytime (40/20°C) and combined high daytime and nighttime (40/30°C) for 4 weeks. Relative to the 30/20°C treatment, plant growth was positively affected by high nighttime temperature and negatively affected by high daytime temperature and combined high day and night temperature. Increased leaf area mainly contributed to increased biomass production in high nighttime temperature; higher nighttime respiration (RN) drove reductions in biomass in combined high daytime and nighttime temperature; and decreased leaf area and AN and increased RN drove reductions in biomass under high daytime temperature alone. AN was not impacted by high nighttime temperature, while decreased under high daytime temperature and increased with combined high daytime and nighttime temperature. Adjustments in leaf traits contributed to increases in AN in combined high daytime and nighttime temperature, and increased photorespiration and respiration contributed to reductions in AN under high daytime temperature. Overall, early season vegetative growth of cotton exhibited differential responses to high daytime and nighttime temperatures.

Mulched drip irrigation and maize straw biochar increase peanut yield by regulating soil nitrogen, photosynthesis and root in arid regions

Biochar has been increasingly recognized as a valuable soil conditioner, which is beneficial to peanut yield improvement. We conducted a three-year field experiment to investigate the effect of biochar applied at three rates (0 t ha−1 (B0), 24 t ha−1 (B1), and 48 t ha−1 (B2), which were 0%, 1%, 2% of the soil mass) on diurnal variation of net photosynthetic rate, soil available nitrogen (N), root characteristics, and peanut yield under two irrigation methods: CK (drip irrigation) and MDI (mulched drip irrigation). A biochar application rate of 24 t ha−1 (B1) increased soil available N, net photosynthetic rate of leaves, and relative chlorophyll values (SPAD) compared to B0. B1 increased total root length, root surface area, root volume and root bleeding sap (RBS) by 8.5∼29.9%, 13.5∼18.5%, 0.8∼12.1%, and 27.6–45.9%, respectively, compared to B0. Significant correlations between grain yield, SPAD, and RBS indicated that biochar enhanced grain yield by improving photosynthesis and root activity. For the irrigation treatments, MDI significantly increased peanut yield, net photosynthetic rate, and RBS, but had no significant effect on soil available N. High biochar application under MDI (IMDIB2) reduced peanut yield in 2020. Moderate biochar application under MDI (IMDIB1) had the highest peanut yield in three years. These results showed that 24 t ha−1 biochar combined with MDI achieved the highest soil available N, root development, and net photosynthetic rate thus which resulted in the highest grain yield, and this could be a management strategy to increase peanut yield.

Analysis of photosynthetic adaptability and shade tolerance of lianas in riverside

This investigation aimed to study the photosynthetic adaptability and shade tolerance of liana in riverside green space. For this purpose, the illumination intensity gradient is set to 2000, 1800, 1500, 1200, 1000, 800, 600, 400, 200, 100, 0 μmol·m-2·s-1, and the corresponding net photosynthetic rate (Pn) value is determined. After the data on the photosynthetic tester is stable, read the value and repeat the measurement 3 times for each gradient; Net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Cond), and intercellular CO2 concentration (Ci) were measured. Instantaneous water use efficiency (WUE) was calculated by Pn/Tr; Typha under different shading conditions was marked, and the leaf number, plant height, crown width, and other growth and development indicators of Typha were observed and recorded regularly. The data were analyzed by software to find out the law of the influence of shading on the growth of Typha. Results showed that the diurnal variation of net photosynthetic rate (Pn) of Typha and Canna showed a "single peak" curve in May and August, and there was no midday depression of photosynthesis, indicating that the two plants had strong adaptability to different light intensities. Shading has a significant impact on the growth of Typha. With the increase of shading degree, the plant height, leaf width and other indicators of Typha have a significant increasing trend, and there is a positive correlation. Still, it is not that the stronger the shading, the better. It is concluded that appropriate light and shade can promote the growth of liana in riverside green space.

Seasonal variations in leaf-level photosynthesis and water use efficiency of three isohydric to anisohydric conifers on the Tibetan Plateau

Different stomatal behaviors among species under drought conditions may affect species-specific seasonal variations in photosynthesis and water use efficiency (WUE), and could enable species to follow differing growth strategies. Here we monitored leaf gas exchange, intra-annual radial growth, leaf stoichiometry, and microclimate of three conifers with contrasting stomatal behaviors (isohydric Picea wilsonii and Pinus tabuliformis vs. anisohydric Juniperus przewalskii) over three growing seasons, and collected tree-ring records of the monitored species, on the cold and arid northeastern Tibet Plateau. We used these data to assess the species-specific seasonal variations in net photosynthetic rate (An), transpiration efficiency (TE) and intrinsic water use efficiency (WUEi), and their impacts on growth.Our observations show that the An of all three conifers was greatest in autumn. This peak was closely related to increasing stomatal conductance following alleviation of drought stress, rather than to variations in leaf nitrogen concentrations. WUEi of the three conifers did not exhibit a regular seasonal pattern, but TE was significantly lower in summer than in spring and autumn, due to the regulation by vapor pressure deficit (VPD). Increasing summer VPD reduced TE mainly by increasing transpiration rate for J. przewalskii and by decreasing An for the isohydric conifers.The increases of An from summer to autumn were much greater for the two isohydric Pinaceae plants than for J. przewalskii. This was consistent with the growth-climate relationships, in which the autumn drought in the previous year limited radial growth of the isohydric conifers more strongly than in the anisohydric conifer. Therefore, we suggest that the growth of isohydric species may profit more from the photosynthates accumulated during the previous post-growing season in the cold and arid Tibetan Plateau.

Effects of growth-promoting strain Mycena sp. M23 on photosynthesis of Aronia melanocarpa

The agronomic traits, chlorophyll content, physiological indices of Aronia melanocarpa were compared in five treatments, namely negative control (CK), positive control (PCK), low dose of microbial inoculant (T1, 50 g per seedling), moderate dose of microbial inoculant (T2, 100 g per seedling), high dose of microbial inoculant (T3, 200 g per seedling) in field. The diurnal variation of net photosynthetic rate was measured by Li-6400 portable photosynthesis system. The diurnal variation of net photosynthetic rate (Pn) of A. melanocarpa showed a pattern of bi-modal curve with photosynthetic "noon break" phenomenon, which occurred at 1:00 pm. At that time, stomatal conductance (gs) and transpiration rate (Tr) of A. melanocarpa showed a dramatic decline, while intercellular CO2 concentration (Ci) significantly rose. It was a photosynthetic "noon break" phenomenon caused by non-stomatal limitation. Application of inoculant to A. melanocarpa successfully avoided the photosynthetic "noon break" phenomenon. Compared with average value of CK and PCK, Pn, gs, Tr, water use efficiency (WUE) and light utilization efficiency (LUE) of inoculation groups increased by 113%, 91%, 50%, 48% and 117% at 1:00 pm. Daily mean of Pn, gs, Tr and LUE of inoculation group was 1.5, 1.9, 1.4 and 1.5 times as that of average value of CK and PCK. The inductive effect of high dose of microbial inoculant treatment was the best among inoculation treatments, with the seedling height 1.2 times as that of the moderate and low inoculant groups. All growth indices, photosynthetic parameters and resistant physiological indices of high dose group were superior to other groups. Our results suggested that fungi M23 could improve the adaptability of A. melanocarpa to environmental stresses and promote its growth by increasing photosynthesis, with the inductive effect of high dose being the best.

Nitrogen fertilization compensation the weak photosynthesis of Oilseed rape (Brassca napus L.) under haze weather

Haze and cloudy weather reduce photo-synthetically active radiation (PAR), which affects the formation of crop yield and nitrogen (N) fertilizer utilization.. We conducted field trails in normal year and severe winter haze year, aiming to compare the difference of photosynthesis and N uptake in winter rapeseed under different N levels. Daily sunshine hours and averaged radiation intensity in winter haze year decreased by 54.1% and 33.3% respectively as compared with the past 30 years. Diurnal variation of net photosynthetic rate in winter haze day was 16.2% lower than that of sunny day. Leaf area and photosynthetic capacity decreased significantly during winter haze year. The shoot biomass and N uptake at the rosette stage accounted for only 9.6% and 26.6% of the total growth period in winter haze year, while 24.4% and 70.5% in normal year, respectively. However, in winter haze year, as the top dressing of N application increasing after the rosette stage, shoot biomass increased gradually. In order to achieve the target yield of 2.5 t ha−1, after suffering winter haze, it is necessary to apply additional 73.1 kg N ha−1. In conclusion, the haze climate reduced the radiation intensity and stability, leading to a decline in photosynthetic productivity in winter oilseed rape. Applying higher N fertilizer after winter haze can compensate the negative influence and ensure rapeseed yield.

Characterization of Oryza nivara introgression lines: A potential prebreeding resource to improve net photosynthetic rate in elite cultivars of rice

Photosynthesis is one of the fundamental processes influencing crop growth and productivity. In order to understand better the basis of variation in net photosynthetic rate (PN) and yield potential in rice, two backcross populations derived from Swarna × O. nivara were studied. Gas exchange and chlorophyll fluorescence measurements were taken at flowering stage and data on yield traits at harvest. PN was significantly correlated with stomatal conductance, transpiration rate, mesophyll conductance, carboxylation efficiency, yield per plant (YLDP), and dry mass in both populations. Ten introgression lines (ILs) showed higher PN than their parents. IL 230S showed highest PN with increased YLDP than the remaining ILs. Single marker analysis showed RM514 and RM48 was positively associated with PN and YLDP in popA, whereas RM204 and RM122 in popB. The first 4 principal components contributed 92 and 93% to the total genetic variation in each population, respectively.

不同类型土壤栽培对苦丁茶树叶片生长和光合特性的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 不同类型土壤栽培对苦丁茶树叶片生长和光合特性的影响 DOI: 10.5846/stxb201806111303 作者: 作者单位: 福建农林大学林学院,贵州大学林学院 作者简介: 通讯作者: 中图分类号: 基金项目: 贵州省科技攻关项目（黔科合NY字[2007]3040号） Effects of different soil types on growth and photosynthetic characteristics of Ligustrum robustum Author: Affiliation: College of Forestry,Fujian Agriculture and Forestry University,College of Forestry,Guizhou University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:研究苦丁茶树叶片生长与光合特性对不同类型土壤栽培的响应特征，确定最适苦丁茶栽培的土壤类型，可为高产优质化的苦丁茶种植业及其规模化生产基地的建立提供科学依据。通过土壤栽培实验研究了不同类型的土壤对苦丁茶树叶片生长、叶片解剖结构、叶绿素含量和光合特性的影响。结果表明：石灰岩土壤栽培条件下，苦丁茶叶长和叶面积比其他6种土壤栽培下的显著提高了34%-57%和43%-68%，叶绿素总量显著增加9%-33%，叶片、上下表皮、海绵组织和栅栏组织的厚度均显著高于其他6种土壤栽培。不同类型土壤栽培下苦丁茶净光合速率（Pn）、气孔导度（Gs）、蒸腾速率（Tr）和饱和蒸气压亏缺（Vpdl）的日变化趋势均呈单峰型，日均Pn和Tr值大小依次为：石灰岩 > 石英砂岩 > 玄武岩 > 长石石英砂岩 > 第四纪红色黏土 > 变余砂岩 > 煤系砂页岩，其中石灰岩土壤栽培下的日均Pn值相比其他6种土壤下的显著提高了13%-45%，且叶片最大净光合速率、表观量子效率、暗呼吸速率、光补偿点（LCP）和光饱和点（LSP）也最大，而煤系砂页岩栽培时最低，其LSP和LCP较石灰岩栽培的分别显著下降了40%和46%。综上，在7种类型的土壤中，石灰岩土壤栽培最有利于苦丁茶树叶片的生长发育、并促进叶绿素的合成和加强对光能的吸收利用，最终提高其叶片光合能力，其次为玄武岩土壤，而煤系砂页岩土壤是最不利于苦丁茶树叶片生长发育和光合作用。建议在苦丁茶种植业的发展和规模化生产基地建立时因选择由石灰岩性母岩发育的土壤进行栽培，从而提高苦丁茶的产量和品质。 Abstract:In this study, we investigated the effects of seven types of cultivation soil on leaf growth and photosynthetic characteristics of Ligustrum robustum (kuding tea) seedlings, aiming to provide scientific advices for cultivation and management of the species for cultivation and management of the species. We measured leaf length, width, area, spongy tissue thickness, palisade tissue thickness, layer of palisade tissue, chlorophyll content, and photosynthetic parameters of the seedlings grown in different soil types. The results showed that cultivation in limestone soil increased the length and area of the leaves by 34%-57% and 43%-68%, respectively, when compared with the other six soil types. In addition, leaf thickness, spongy tissue, and palisade tissue were significantly higher, and total chlorophyll content was 9%-33% higher in the limestone soil than in the other six soil types. The soil types did not affect the diurnal variation in net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and vapor pressure deficit (Vpdl). The daily average of Pn and Tr values in the seven soil types in descending order were as follows:limestone > quartz sandstone > basalt > feldspathic quartz sandstone > quaternary red clay > blastopsammite > coal sand shale. The daily average of Pn value was 13%-45% higher in limestone soil than in the other six soil types. Pn, Gs, and Tr were positively correlated, but they were negatively correlated with Vpdl. The maximum net photosynthetic rate, light saturation (LSP), light compensation (LCP), dark respiration rate, and apparent quantum yield were observed in limestone soil. LSP and LCP were significantly lower in coal sand shale soil (40% and 46%, respectively) than in the limestone soil. In summary, limestone soil is most beneficial for the growth and development of leaves. It can promote the production of chlorophyll and thus enhance the absorption and utilization of light energy and improve leaf growth and photosynthetic capacity. The second appropriate soil type is basalt. In contrast, coal sand shale soil is most unfavorable for the growth and development of leaves and photosynthesis. Therefore, limestone soil should be used for the large-scale plantation of L. robustum and improvement of the yield and quality of kuding tea. 参考文献 相似文献 引证文献

Responses of diurnal variation of flag-leaf photosynthesis and photosynthetic pigment content to elevated atmospheric CO2 concentration and temperature of Japonica rice during late growth stage: A FACE study.

A local popular Japonica rice (Oryza sating L.) cultivar, Nanjing 9108, was tested with free air controlled enrichment (FACE) approach to study the responses of photosynthetic pigment content and diurnal variation of flag-leaf photosynthesis to elevated atmospheric CO2 concentration and temperature. Four alternative treatments were designed with two CO2 concentration levels (ambient and elevated 200 μmol·mol-1) and two air temperature regimes (ambient and elevated 1-2 ℃). Diurnal variation of flag-leaf photosynthesis was measured in the middle full stage and the late full stage, and photosynthetic pigment of the leaf was analyzed afterward. Results showed that diurnal variation of net photosynthetic rate (Pn) in each treatment followed a double-peak curve with midday depression feature during late growth stage. Compared to Pn under ambient condition, Pn under elevated CO2 concentration increased by 47.6% and 39.1% on average at middle full stage and late full stage, respectively. There was a negative correlation between temperature and Pn with no significance. Both elevated CO2 concentration and temperature had a significant negative effect on stomatal conductance (gs), decreased by 17.0% and 11.8% on average, respectively. Elevated CO2 concentration significantly reduced transpiration rate (Tr), chlorophyll a (Chl a), chlorophyll b (Chl b), carotene (Car), total chlorophyll (Chl t) and chlorophyll a/b ratio (Chl a/b) during late growth stage of rice by 5.9%, 50.4%, 21.3%, 41.4%, 39.4% and 21.4% on average, respectively, whereas water use efficiency (WUE) increased by 47.9%. However, there were opposite effects on Tr, WUE and photosynthetic pigment content under elevated temperature, with Tr increased by 10.2% and WUE decreased by 20.4%. It could be concluded that elevated CO2 concentration had a greater effect on Pn, gs and photosynthetic pigment content of rice leaf than elevated temperature did during late growth stage. Therefore, it should be paid more attention to the colligate effects of elevated CO2 concentration and high temperature on photosynthesis and photosynthetic pigment content to reduce negative effect of high air temperature.

Effects of light quality on growth, total gypenosides accumulation and photosynthesis in Gynostemma pentaphyllum

Gynostemma pentaphyllum is a kind of shade–tolerant plants. It can synthesize and accumulate gypenosides in large amounts. The gypenosides are a valuable medicine. To develop effective cultivation techniques of the plant, effects of light quality on growth, accumulation of total gypenosides and photosynthesis in G. pentaphyllum were investigated in this study. Results showed that light quality had remarkable effect on plant growth. White light had a significant effect on the increase in growth, especially in highest biomass, stem diameter and newly sprouted leaves. Red light accelerated stem length, new leaf formation and biomass when compared with blue and green lights. By contrast, green light had influence on inhibiting the increase of growth and biomass. And moreover, the content of total gypenosides was different in seedlings under different lights. The content of total gypenosides was the highest rank under red and white lights, followed by the content under blue light. The content was the least under green light. The diurnal variation of net photosynthetic rate exhibited a typical double-peak curve when the plant grown under white, red and blue lights respectively, while that under green light presented a single-peak curve. The net photosynthetic rate (Pn) under red light was higher than those under either blue or green lights, but obviously lower than that under white light. The diurnal variation curve of stomatal conductance closely paralleled to that of transpiration rate curve, whereas the curve of intercellular CO2 concentration exhibited an opposite trend to that of Pn under any of the four lights. It was suggested that the influence of monochromatric light quality on growth and the accumulation of total gypenosides was associated with photosynthesis efficiency.

Introgressions from Oryza rufipogon Increase Photosynthetic Efficiency of KMR3 Rice Lines

To understand the wild Oryza genome effect on photosynthesis and its relation to total dry matter accumulation in an elite rice variety, a set of 40 stable introgression lines (ILs) BC3F8 derived from a cross of Oryza sativa (KMR3) × Oryza rufipogon (WR120) were grown under well watered conditions. Leaf gas exchange measurements and leaf chlorophyll estimates were conducted at the flowering stage. The results revealed significant variations in net photosynthetic rate (Pn), transpiration rate (E), transpiration efficiency (Pn/E) and carboxylation efficiency (Pn/Ci). Pn showed significant positive correlation with E, stomatal conductance (gs), Pn/Ci and total canopy dry matter. Specific leaf area and leaf thickness were not significantly correlated with Pn. Thirty-seven out of 40 ILs showed higher Pn than KMR3 [11.28μmol/(m2·s)], and 20 ILs showed higher Pn than WR120 [15.08μmol/(m2·s)]. The line IL194 showed the highest Pn [21.62μmol/(m2·s)] with increased total canopy dry matter followed by lines IL381, IL106, IL363-12, IL198, IL86-18 and IL50, which exhibited Pn above 18.0μmol/(m2·s). The ILs with enhanced Pn are a potential source for developing rice varieties and hybrids with higher biomass and yield.

Population dynamics of Meloidogyne incognita on cucumber grafted onto the Cucurbita hybrid RS841 or ungrafted and yield losses under protected cultivation

The influence of the squash hybrid RS841 rootstock (Cucurbita maxima x C. moschata) on population dynamics of Meloidogyne incognita and yield of cucumber cv. Dasher II was assessed during 2013 and 2014 in a plastic greenhouse. In addition, the relationship between ecophysiological parameters (plant water status, gas exchange, and leaf reflectance) and Pi and cucumber yield were also estimated in 2013. Nematode densities were determined at the beginning (Pi) and at the end (Pf) of each crop, and the relationship between these parameters was used to estimate the maximum multiplication rate (a), the maximum population density (M) and the equilibrium density (E) per grafted and ungrafted cucumber and cropping season. Moreover, the relationship between the multiplication rate (Pf/Pi) and Pi was compared between grafted and ungrafted cucumber per cropping season. Finally, the relative yield of grafted or ungrafted cucumber was plotted against Pi to determine the tolerance limit (T) and the minimum relative yield (m) by the Seinhorst damage function model. Values of a, M and E in grafted cucumber were higher than in ungrafted one irrespective of the cropping season. These results were supported by comparing the relationship between Pf/Pi and Pi between grafted and ungrafted cucumber. The relationship between Pi and yield fitted the Seinhorst damage function. The values of T and m did not differ between grafted and ungrafted each year. Predawn water potential, net photosynthetic rate, and leaf chlorophyll index decreased with increasing Pi. In addition, relative yield was related to variation in net photosynthetic rate and the leaf chlorophyll index. Under the conditions of this study, RS841 rootstock was neither resistant nor tolerant to M. incognita.

Vertical distribution characteristics of photosynthetic parameters for Phragmites australis in Liaohe River Delta wetland, China

ABSTRACTA field experiment was undertaken to measure diurnal variation in photosynthetic and light-response parameters of leaves of Phragmites australis growing in the Liaohe River Delta wetland, China. Four developmental stages (leaf-expansion, jointing, heading, and mature stages) and three (upper, middle, and lower layers) or five vertical layers (top, upper, middle, lower, and bottom layers) were delimited. Diurnal variations in net photosynthetic rate, stomatal conductance, and transpiration rate showed single-peak or double-peak curves that were lower in the morning and evening and higher at noon. The diurnal variation in intercellular CO2 concentration showed the opposite pattern, with higher values in the morning and evening and lower values at noon. Midday depression was observed under strong light, in the top, upper, and middle layers but not under weak light or in the lower and bottom layers. The net photosynthetic rate, stomatal conductance, and transpiration rate were higher in the upper layer, and gradually decreased in value and in diurnal variability below the middle layer with increasing proximity to the plant base. Leaves showed a strong photosynthetic ability at the leaf-expansion stage, with the maximum net photosynthetic rate in the middle layer and the minimum net photosynthetic rate in the lower layer. Photosynthetic ability increased at the jointing and heading stages. The maximum net photosynthetic rate was in the upper or middle layers and the minimum in the bottom layer. Photosynthetic ability was weak at the mature stage. The light compensation point in leaves was 27.1–38.2, 24.6–29.5, 27.7–72.6, and 15.4–31.0 μmol⋅m−2⋅s−1 at the leaf-expansion, jointing, heading, and mature stages, respectively. The developmental stages of P. australis leaves were ranked, from highest ability to use weak light to lowest, as follows: mature stage > jointing stage > leaf-expansion stage > heading stage.

Effects of elevated CO2 concentration on water use efficiency of Tamarix ramosissima in an extremely arid region

The variation of net photosynthetic rate (Pn), transpiration rate (Tr), and intercellular CO2 concentration (Ci) with changes in light intensity of Tamarix ramosissima leaves was studied during the growing seasons of 2012 and 2013 in the extremely arid region of Ejina Oasis, using the LI-6400 portable photosynthesis measurement system. Results indicate that Ci decreased and Pn and Tr increased with light intensity. After reaching the light saturation point, Pn decreased gradually with the enhanced greater light intensity. The apparent maximum photosynthetic rate increased with CO2 concentration, from 17.69 to 27.05 µmol/(m2 s); apparent quantum efficiency also increased, as did the light saturation point of T. ramosissima leaves. Water use efficiency (WUE) increased initially but gradually decreased after maximizing with the enhanced light intensity. Tr and Ci increased with elevated CO2 concentration. Pn and WUE increased with CO2 concentration when that concentration was 200–600 µmol/mol. When that concentration increased to 1000 µmol/mol, WUE increased initially but eventually decreased.

元谋干热河谷一种景观树种羊蹄甲的光合特性研究

通过对羊蹄甲的光合速率、气孔导度及其相应环境因子的测定，探讨元谋干热河谷羊蹄甲的光合生理生态特征。本研究采用TPS-1 (英国PPsystems公司出品)便携式光合测定系统对元谋县县城绿化树羊蹄甲的光合特性进行了研究，结果表明：羊蹄甲净光合速率的日变化成双峰曲线，光照强度(PAR)、蒸腾速率(Tr)、胞间CO2浓度(CI)、大气CO2浓度(Ca)、气孔导度(GS)、温度(T)等因子都会影响羊蹄甲的净光合速率，羊蹄甲对光能的利用率平均值为0.03 mmol∙mol−1，对水分的利用率平均为2.061 mmol∙mol−1。羊蹄甲在元谋干热河谷有较强的适应性。 In order to study the photosynthetic characteristics of Bauhinia blakeana, the photosynthetic rate, stomatal conductance and its corresponding environmental factors were measured. Photosynthetic characteristics of Bauhinia blakeana, a kind of greening tree species in Yuanmou County, were measured by using TPS-1 portable photosynthetic measurement system (produced by PPsystems Company in the British). The results showed that the daily variation of net photosynthetic rate of Bauhinia blakeana showed bimodal curve. The factors of photosynthetic active radiation (PAR), transpiration rate (Tr), intercellular CO2 concentration (Ci), atmospheric CO2 concentration (Ca), stomatal conductance (Gs) and temperature (T) impacted on the net photosynthetic rate of Bauhinia blakeana. The average value of light use efficiency was 0.03 mmol∙mol−1, and water use efficiency was 2.061 mmol∙mol−1. Bauhinia blakeana had stronger adaptation in Yuanmou dry-hot valleys.

Effect of Light Intensity on Leaf Photosynthetic Characteristics and Accumulation of Flavonoids in <i>Lithocarpus litseifolius</i> (Hance) Chun. (Fagaceae)

The active compounds in herb drugs are mainly secondary metabolites, which are greatly influenced by external conditions. Particularly, light intensity has a great influence on the photosynthesis and accumulation of secondary metabolites. In this study, the light intensity was changed, and the influence of the light intensity on leaf photosynthetic characteristics, antioxidant enzyme activity and flavone contents of Lithocarpus litseifoliusp (Hance) Chun. was discussed. The results showed that (1) L. litseifolius is a typical heliophyte. As the light intensity decreased, the contents of chlorophyll a (Chl a), chlorophyll b (Chl b) and total chlorophyll (Chl a + b) all increased. However, the Chl a/b ratio gradually decreased. The daily variation of net photosynthetic rate changed from a double-peak curve under natural light to single-peak curve under 20% full light two shading nets. (2) As the light intensity decreased, the SOD and POD activities and the soluble proteins content decreased in the leaves. In contrast, the malondialdehyde content increased. (3) The flavone content was the highest in leaves at one shading nets 60% of full light, and the lowest occurred in leaves at two shading nets 20% of full light. A comprehensive analysis indicated that an appropriate shading could induce shade tolerance in the leaves of L. litseifolius, which promoted the accumulation of flavonoids. L. litseifolius should be planted in the lower position of sunny slope or the upper position of shady slope to increase the content of flavone in the leaves.

Interpopulation Differences in Salinity Tolerance of the Invasive Cordgrass Spartina densiflora: Implications for Invasion Process

The invasive cordgrass, Spartina densiflora, has demonstrated a high tolerance to salinity stress. However, no attempt has yet been made to assess the intra-specific variation in salinity tolerance among S. densiflora populations. The aim of this study was to analyze the effects of provenance and salinity (0, 80, 170, 510, and 1023 mM NaCl) on germination, seedling survival, growth, and physiological performance of S. densiflora adult plants from three populations of the Gulf of Cadiz (Odiel, Tinto, and Piedras, SW Spain). Our results indicate that a salinity increment decreased germination and seedling survival of all S. densiflora populations, but these impairments were also dependent on the original population of the seeds. Accordingly, the Odiel population showed greater germination (70 %) and seedling survival (86 %) percentages at 510 mM NaCl than Tinto and Piedras populations, with mean percentage values of 57 % germination and 55 % seedling survival. These differences were also clearly reflected in long-term measurements, such as those regarding total dry mass, relative growth rate, and tiller number, which were mainly determined by the extent of photosynthetic area rather than the variations in net photosynthetic rate. Also, the higher tolerance of the Odiel population could be partly explained by a reduced level of Na in its tissues. Consequently, all populations might have the ability to colonize brackish marshes and river banks, but their invasion would be severely limited under hypersaline conditions, except in the case of the Odiel population, which would have a greater capacity for invasion of sub-optimal habitats, such a salt pans.

接种土壤微生物对铜胁迫下海州香薷生长及光合生理的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 接种土壤微生物对铜胁迫下海州香薷生长及光合生理的影响 DOI: 10.5846/stxb201308212125 作者: 作者单位: 上海师范大学生命与环境科学学院,台州学院生态研究所,台州学院生态研究所,山西师范大学,台州学院生态研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 浙江省自然科学基金项目(LY12C03002) Effects of soil microbe inoculation on the growth and photosynthetic physiology of Elsholtzia splendens under copper stress Author: Affiliation: School of Life and environment Science,Shanghai Normal University,Institute of Ecology,Taizhou University,Institute of Ecology,Taizhou University,,Institute of Ecology,Taizhou University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:采用框栽试验方法,模拟Cu胁迫条件下,探讨接种土壤微生物对海州香薷(Elsholtzia splendens)生长和光合生理的影响。结果表明:(1)在Cu胁迫下,海州香薷株数、株高、基径、生物量、茎重比均显著低于对照;与Cu胁迫相比,接种土壤微生物能显著缓解Cu胁迫对海州香薷生长的抑制作用,使植株的株数、株高、生物量、茎重比显著提高。Cu胁迫下,接种土壤微生物均降低了植株体内不同器官Cu含量,茎和叶Cu的累积量显著减少,但对其它器官的Cu含量影响不显著。(2)秋季,各处理的海州香薷的净光合速率(Pn)日变化均呈"单峰"曲线,接种土壤微生物显著提高了Cu胁迫下海州香薷的日均Pn、日均蒸腾速率(Tr),而日均气孔导度(Gs)、日均胞间CO2浓度(Ci)显著降低。(3)Cu胁迫下,接种土壤微生物显著提高了植株的最大净光合速率(Pnmax)、光饱和点(LSP)、表观量子效率(AQY)、最大羧化速率(Vcmax)、最大电子传递速率(Jmax)、磷酸丙糖利用率(TPU),且使光补偿点(LCP)显著降低。表明接种土壤微生物通过提高光能利用率、利用弱光和碳同化能力来增强光合作用能力及有机物的积累,缓解Cu胁迫对海州香薷的毒害。因此,接种土壤微生物可促进Cu胁迫下海州香薷的生长,在重金属污染土壤的植物修复中具有较好的应用潜力。 Abstract:Phytoremediation, an emerging cost effective and ecologically benign technology for the decontamination of soils, is the use of plants and their associated microbes for environmental cleanup. The efficiency of phytoremediation depends mostly on the establishment of robust plant-microbe interactions. Elsholtzia splendens is a Labiatae plant well known for its high copper tolerance, which is widely distributed on copper deposits as well as non-contaminated areas. It has been considered for the phytoremediation of copper polluted soils; however, little is known about the role of the soil microbe community in the roots of E. splendens in adapting the non-contaminated plants to copper stress. In order to evaluate the effects of inoculation with soil microbes on the copper tolerance of E. splendens, this experiment studied the effect of inoculation with soil microbes on the seedling dry weight, plant morphology, survival rate, copper content and leaf gas exchange parameters of E. splendens under copper stress using a mesocosm system. The experiment included four soil treatments: the addition of copper (copper stress); soil microbe inoculation; addition of copper and soil microbe inoculation; and no additional copper or soil microbe inoculation (control). The results were as follows: (1) The plant number, plant height, basal diameter, biomass, and stem weight ratio of E. splendens under copper stress were lower than in the control. Inoculation with soil microbes significantly increased the plant number, plant height, biomass, and stem weight ratio of E. splendens under copper stress, indicating an alleviation effect on the inhibition of copper on the growth of E. splendens. Compared with the control, the copper content of roots, stems, leaves, inflorescences and seeds were increased under copper stress. Under copper stress, soil microbe inoculation significantly decreased copper content in the stem and leaf organs of E. splendens, but did not markedly affect copper content in the other organs. (2) In autumn, the diurnal variation in net photosynthetic rate (Pn) in the leaves of E. splendens under all treatments took on a one-peak curve. Inoculation with soil microbes significantly increased the daily mean Pn and daily mean transpiration rate (Tr), and significantly decreased the daily mean stomatal conductance and daily mean intercellular CO2 concentration (Ci) of E. splendens under copper stress. (3) Under copper stress, the maximum net photosynthetic rate (Pnmax), light saturation point (LSP), apparent quantum yield (AQY), maximum rate of carboxylation (Vcmax), maximum rate of electron transport (Jmax) and the triose phosphate use rate (TPU) of E. splendens significantly decreased, while the light compensation point (LCP) significantly increased. Inoculation with soil microbes significantly increased the Pnmax, LSP, AQY, Vcmax, Jmax and TPU, but decreased the LCP. In conclusion, inoculation with soil microbes can effectively alleviate the damage of copper stress to E. splendens by increasing the photosynthetic ability, enhancing the light energy utilization and carbon assimilation and promoting the accumulation of organic matter. Inoculation with soil microbes can increase the growth of plants under copper stress, which could have potential applications in the phytoremediation of soils contaminated with heavy metals. 参考文献 相似文献 引证文献

Analysis of photosynthetic characteristics and its influencing factors of medicinal plant Mirabilis himalaica

To study photosynthetic characteristics and its influencing factors in leaves of medicinal plant Mirabilis himalaica, and provide an evidence for guiding artificial planting and improving the quantity. The light-response and diurnal photosynthesis course of leaves at the booting stages of 1-3 year old M. himalaica were measured with LI-6400 system. The Results showed that the light response curves were fitted well by non rectangle hyperbola equation (R2 > or = 0.98). The values of the maximum photosynthetic rate (Pmax) and light use efficiency of three-year old M. himalaica leaves were higher than those of 1-2 year old individuals. The diurnal variation of net photosynthetic rate (Pn) and stomatal conductance (Gs) of 2-3 year old M. himalaica were typical double-peak curves determinately regulated by stomatal conductance. However, transpiration rate (Tr) of 1-3 year old plants leaves were single-peak curve, which was self-protection of harm reduction caused by the higher temperature at noontime. Correlation analysis showed that the changes between photosynthetic active radiation (PFD), air temperature (T ) and Pn, were significant positive related. Therefore, M. himalaica is a typical sun plant, which should be planted under the sufficient sunshine field and prolong the growing ages suitably in order to improve the yield.

Effect of fertilization on photosynthetic characteristics of wheat flag leaf

用LI-6400观测氮磷钾用量对小麦旗叶光合特性日变化的影响, 试验设4个处理, 分别为高氮低磷高钾(N4P2K2)、无氮无磷高钾(N1P1K2)、无氮高磷无钾(N1P3K1)和高氮高磷无钾(N4P3K1), 试验结果表明: N4P2K2处理对小麦旗叶光合作用有利; 而由于N4P3K1处理缺少钾元素且氮磷过量, 小麦旗叶光合速率(<i>P_n</i>)较低; N1P1K2和N1P3K1处理下光合作用较弱。对同种处理下不同时期小麦旗叶光合速率日变化的比较, N1P3K1处理在3个生育时期的旗叶光合速率差别较大, N4P2K2与N1P1K2处理在各生育期光合作用的差别表现居中, N4P3K1处理各时期的旗叶光合速率差别最小。N1P1K2处理小麦成熟期的光合速率仍然保持较高水平, 钾肥在小麦成熟期影响较大。