Plant Physiological Activities Research Articles

Effect of phosphorus application rate on Mentha spicata L. grown in deep flow technique (DFT).

The present study evaluated the impact of phosphorus application rate on plant growth and physiological parameters, antioxidant activity, chemical composition, and essential oil yield and composition of hydroponically grown spearmint plants. Increased P levels resulted in high dry matter content of the aerial part. Antioxidant activity of spearmint leaves was significantly higher at the highest P levels. Although essential oil yield was not affected, essential oil composition varied among the studied P levels, especially carvone content. Total and individual organic acids content was higher when 50 mg/L P were added in the nutrient solution. Rosmarinic acid was the main detected phenolic compound, while the highest total phenolic compounds and rosmarinic acid content was observed at 50 and 70 mg/L of P, respectively. In conclusion, phosphorus application rate may affect spearmint growth and development, as well as chemical composition and essential oil composition.

Role of chitosan on the growth, physiological parameters and enzymatic activity of milk thistle (Silybum marianum (L.) Gaertn.) in a pot experiment

Salt stress is the destructive factor in plant growth and physiological activities. Using biobased stimulants, such as chitosan, is important to reduce the adverse effects of salinity. This study was carried out in a greenhouse located at the University of Tehran, in 2016. The goal of this study was to evaluate the effect of chitosan application on modification of adverse effects of soil salinity on growth and physiological characteristics of milk thistle (Silybum marianum (L.) Gaertn.). A pot experiment with a factorial arrangement of treatments was conducted based on a randomized complete block design (RCB) with three replications Four irrigation water salinity levels were control (tap water 0.8), 4, 8 and 12 dS/m and four levels of chitosan were mixed with dry soil to yield 0, 0.01, 0.05 and 0.1% chitosan (DW/DW). The results showed that salinity reduced root dry weight; shoot dry weight, total plant biomass, and increased soluble sugars, proline content, CAT spell out first use and POD spell out first use enzyme activity and H2O2 concentration in leaves. The use of chitosan led to a reduction of salinity adverse effects and increased plant growth and improved physiological traits. Chitosan application at 0.01% increased chlorophyll a and total chlorophyll and at 0.05% level increased chlorophyll b compared to other chitosan treatments. The highest concentration of soluble sugars and proline was achieved by chitosan application across all salinity levels. Chitosan application under 0.01 and 0.05% enhanced the enzymatic activity and decreased H2O2 concentration in leaves. The results illustrated that chitosan could protect plants from salt stress damage by modulating intracellular ion concentration and by enhancing the capacity of antioxidant enzyme activities. It seems that the average concentration of chitosan as a bio-stimulant (0.01 and 0.05%) plays a positive role in reducing salinity and enhancing growth in milk thistle.

Effect of Vegetation on the Energy Balance and Evapotranspiration in Tallgrass Prairie: A Paired Study Using the Eddy-Covariance Method

We carried out a paired study in tallgrass prairie to evaluate the influence of vegetation on the energy exchange and evapotranspiration. Two eddy-covariance systems were installed over two adjoining sites, one of which was denuded of vegetation, with the adjacent, control site kept undisturbed. Our year-long investigation shows that, for quantifying the ground surface heat flux, the soil heat storage above the soil plates is more important than the sub-surface soil heat flux, both temporally and in magnitude. The incorporation of the soil heat storage, therefore, is indispensable for energy balance closure in areas with short vegetation. At our control site, we observed a critical threshold of 0.17 m3 m−3 in the surface (top 0.3 m) soil water content, whereby the energy partitioning is significantly affected by the presence of the photosynthetically active vegetation when the surface soil water content is higher than this critical threshold. The pattern of energy partitioning approaches that of the treated site when the surface soil water content is lower than this threshold (during drought), because of the suppression of plant physiological activities. This threshold also applies to the surface conductance for water vapour at the control site, where yearly evapotranspiration is 728 ± 3 mm (versus 547 ± 2 mm for the treated site). Thus, the soil water content and presence of active vegetation are the key determinants of energy partitioning and evapotranspiration. Any land-cover changes or vegetation-management practices that alter these two factors may change the energy and water budgets in tallgrass prairie.

A genome-wide analysis of SWEET gene family in cotton and their expressions under different stresses

BackgroundThe SWEET (Sugars will eventually be exported transporters) gene family plays multiple roles in plant physiological activities and development process. It participates in reproductive development and in the process of sugar transport and absorption, plant senescence and stress responses and plant-pathogen interaction. However, thecomprehensive analysis of SWEET genes has not been reported in cotton.ResultsIn this study, we identified 22, 31, 55 and 60 SWEET genes from the sequenced genomes of Gossypium arboreum, G. raimondii, G. hirsutum and G. barbadense, respectively. Phylogenetic tree analysis showed that the SWEET genes could be divided into four groups, which were further classified into 14 sub-clades. Further analysis of chromosomal location, synteny analysis and gene duplication suggested that the orthologs showed a good collinearity and segmental duplication events played a crucial role in the expansion of the family in cotton. Specific MtN3_slv domains were highly conserved between Arabidopsis and cotton by exon-intron organization and motif analysis. In addition, the expression pattern in different tissues indicated that the duplicated genes in cotton might have acquired new functions as a result of sub-functionalization or neo-functionalization. The expression pattern of SWEET genes showed that the different genes were induced by diverse stresses. The identification and functional analysis of SWEET genes in cotton may provide more candidate genes for genetic modification.ConclusionSWEET genes were classified into four clades in cotton. The expression patterns suggested that the duplicated genes might have experienced a functional divergence. This work provides insights into the evolution of SWEET genes and more candidates for specific genetic modification, which will be useful in future research.

Inoculation of Brevibacterium linens RS16 in Oryza sativa genotypes enhanced salinity resistance: Impacts on photosynthetic traits and foliar volatile emissions

The emission of volatiles in response to salt stress in rice cultivars has not been studied much to date. Studies addressing the regulation of stress induced volatile emission by halotolerant plant growth promoting bacteria containing ACC (1-aminocyclopropane-1-carboxylate) deaminase are also limited. The objective of the present study was to investigate the salt alleviation potential of bacteria by regulating photosynthetic characteristics and volatile emissions in rice cultivars, and to compare the effects of the bacteria inoculation and salt responses between two rice genotypes. The interactive effects of soil salinity (0, 50, and 100 mM NaCl) and inoculation with Brevibacterium linens RS16 on ACC accumulation, ACC oxidase activity, carbon assimilation and stress volatile emissions after stress application were studied in the moderately salt resistant (FL478) and the salt-sensitive (IR29) rice (Oryza sativa L.) cultivars. It was observed that salt stress reduced foliage photosynthetic rate, but induced foliage ACC accumulation, foliage ACC oxidase activity, and the emissions of all the major classes of volatile organic compounds (VOCs) including the lipoxygenase pathway volatiles, light-weight oxygenated volatiles, long-chained saturated aldehydes, benzenoids, geranylgeranyl diphosphate pathway products, and mono- and sesquiterpenes. All these characteristics scaled up quantitatively with increasing salt stress. The effects of salt stress were more pronounced in the salt-sensitive genotype IR29 compared to the moderately salt resistant FL478 genotype. However, the bacterial inoculation significantly enhanced photosynthesis, and decreased ACC accumulation and the ACC oxidase activity, and VOC emissions both in control and salt-treated plants. Taken together, these results suggested that the ACC deaminase-containing Brevibacterium linens RS16 reduces the temporal regulation of VOC emissions and increases the plant physiological activity by reducing the availability of ethylene precursor ACC and the ACC oxidase activity under salt stress.

A positive response of rice rhizosphere to alternate moderate wetting and drying irrigation at grain filling stage

Paddy fields are drained and irrigated several times during the whole rice growth period. Although studies have acknowledged the sensitivity of flooding and drainage in rice rhizosphere, current knowledge regarding how moderate drying at grain filling stage affects ecological characteristics of rice rhizosphere is limited. A field experiment with two irrigation regimes [alternate moderate wetting and drying irrigation (AMWD) and continuous irrigation (CI)] was conducted to investigate the changes in soil physical and chemical properties and microbial communities. Results from this investigation demonstrated that soil pH under AMWD was decreased, while Eh was increased. Moreover, soil electrical conductivity increased and decreased with a decline in soil water potential, interestingly all studied variables quickly recovered after re-watering.The terminal restriction fragment length polymorphism (T-RFLP) analysis revealed that the diversity indices of bacterial communities were higher in drying phase as compared to the initial treatment of AMWD regime, but the evenness index decreased. Remarkably, AMWD process increased the proportion of aerobic bacteria, such as Azotobacter, nitrifying bacteria, phosphate and potassium solubilizing bacteria (which participate in the nutrient cycling). In addition, the increase of enzyme activity under AMWD regime promoted the release of nutrients, thereby enhancing the amounts of NO3−-N, available phosphorus (P) and potassium (K) in soils, which met rice nutrient demands at late grain filling stage. This led to a promotion in plant physiological activities and grain filling, and hence increased grain yield. From these results we infer that there was a positive response of rice rhizosphere to AMWD irrigation at grain filling stage, which laid the groundwork to set up a sound irrigation system in rice fields without reducing its yield.

BnaA.bZIP1 Negatively Regulates a Novel Small Peptide Gene, BnaC.SP6, Involved in Pollen Activity.

Small peptides secreted to the extracellular matrix control many aspects of the plant’s physiological activities which were identified in Arabidopsis thaliana, called ATSPs. Here, we isolated and characterized the small peptide gene Bna.SP6 from Brassica napus. The BnaC.SP6 promoter was cloned and identified. Promoter deletion analysis suggested that the -447 to -375 and -210 to -135 regions are crucial for the silique septum and pollen expression of BnaC.SP6, respectively. Furthermore, the minimal promoter region of p158 (-210 to -52) was sufficient for driving gene expression specifically in pollen and highly conserved in Brassica species. In addition, BnaA.bZIP1 was predominantly expressed in anthers where BnaC.SP6 was also expressed, and was localized to the nuclei. BnaA.bZIP1 possessed transcriptional activation activity in yeast and protoplast system. It could specifically bind to the C-box in p158 in vitro, and negatively regulate p158 activity in vivo. BnaA.bZIP1 functions as a transcriptional repressor of BnaC.SP6 in pollen activity. These results provide novel insight into the transcriptional regulation of BnaC.SP6 in pollen activity and the pollen/anther-specific promoter regions of BnaC.SP6 may have their potential agricultural application for new male sterility line generation.

Genome-wide identification and expression profile analysis of CCH gene family in Populus.

Copper plays key roles in plant physiological activities. To maintain copper cellular homeostasis, copper chaperones have important functions in binding and transporting copper to target proteins. Detailed characterization and function analysis of a copper chaperone, CCH, is presently limited to Arabidopsis. This study reports the identification of 21 genes encoding putative CCH proteins in Populus trichocarpa. Besides sharing the conserved metal-binding motif MXCXXC and forming a βαββαβ secondary structure at the N-terminal, all the PtCCHs possessed the plant-exclusive extended C-terminal. Based on their gene structure, conserved motifs, and phylogenetic analysis, the PtCCHs were divided into three subgroups. Our analysis indicated that whole-genome duplication and tandem duplication events likely contributed to expansion of the CCH gene family in Populus. Tissue-specific data from PlantGenIE revealed that PtCCH genes had broad expression patterns in different tissues. Quantitative real-time RT-PCR (qRT-PCR) analysis revealed that PnCCH genes of P. simonii × P. nigra also had different tissue-specific expression traits, as well as different inducible-expression patterns in response to copper stresses (excessive and deficiency). In summary, our study of CCH genes in the Populus genome provides a comprehensive analysis of this gene family, and lays an important foundation for further investigation of their roles in copper homeostasis of poplar.

Localized surface plasmon resonance-based abscisic acid biosensor using aptamer-functionalized gold nanoparticles.

Abscisic acid (ABA) plays an important role in abiotic stress response and physiological signal transduction resisting to the adverse environment. Therefore, it is very essential for the quantitative detection of abscisic acid (ABA) due to its indispensable role in plant physiological activities. Herein, a new detection method based on localized surface plasmon resonance (LSPR) using aptamer-functionalized gold nanoparticles (AuNPs) is developed without using expensive instrument and antibody. In the presence of ABA, ABA specifically bind with their aptamers to form the ABA-aptamer complexes with G-quadruplex-like structure and lose the ability to stabilize AuNPs against NaCl-induced aggregation. Meanwhile, the changes of the LSPR spectra of AuNP solution occur and therefore the detection of ABA achieved. Under optimized conditions, this method showed a good linear range covering from 5×10−7 M to 5×10−5 M with a detection limit of 0.33 μM. In practice, the usage of this novel method has been demonstrated by its application to detect ABA from fresh leaves of rice with the relative error of 6.59%-7.93% compared with ELISA bioassay. The experimental results confirmed that this LSPR-based biosensor is simple, selective and sensitive for the detection of ABA. The proposed LSPR method could offer a new analytical platform for the detection of other plant hormones by changing the corresponding aptamer.

Effectiveness of Zinc and Gypsum Application Against Cadmium Toxicity and Accumulation in Wheat (Triticum aestivum L.)

ABSTRACTCadmium (Cd) is a nonessential and toxic element because it inhibits the growth and development of plants and is dangerous for end consumer. It enters in the human food chain through food crops. Application of plant nutrients such as zinc (Zn) and gypsum is a viable and cheap strategy to minimize its accumulation in edible plant portions. Therefore, this investigation was conducted to determine the effectiveness of Zn and gypsum against Cd accumulation in wheat. The results showed that Cd toxicity considerably decreased the plant growth, physiological activities, and yield attributes and increased the Cd accumulation in root, shoot, and grain, while application of Zn and gypsum remarkably increased the growth and yield and decreased the Cd accumulation in plant parts in Cd-contaminated soil. The results also depicted that application of Zn showed better results as compared to gypsum. In conclusion, we can say that application of Zn and gypsum remarkably ameliorated the Cd toxicity and decreased its accumulation in wheat, grown in Cd-contaminated soil.

KEMAMPUAN DUA SPESIES Enterobacter sp. SEBAGAI BAKTERI PEMACU PERTUMBUHAN TANAMAN KENTANG (Solanum tuberosum L.) PADA KONDISI CEKAMAN KEKERINGAN

Enterobacter xiangfangensis and Enterobacter cloaceae are known to have the ability as a phosfat solubilizing and producing hormone IAA. Their also have ability to survive under drought stress in vitro assay conditions. Both of these bacteria has good potential as a potato plant growth promoting bacteria, especially in drought stress conditions. This is an alternative to improve tolerance and growth of the potato crop in drought stress conditions. The results showed that the level of drought stress 75% of field capacity can boost the potential of endophytic bacteria E. xiangfangensis in increasing leaf area, plant dry weight, root length and physiological activity i.e total phosphorus content in potato plants. Endophytic bacteria E. xiangfangensis is better to increase potato plant height than endophytic bacteria E. cloaceae. These results are supported by the results of potential test of E. xiangfangensis which have the advantage of producing hormones IAA compared with E. cloaceae. Furthermore, in drought stress conditions 50% of field capacity and 75% of field capacity have different effects on the observations of root length growth parameters potato plants.

草炭,風化炭から抽出した腐植酸,フルボ酸のイネに対する生理活性効果

草炭,風化炭から抽出した腐植酸,フルボ酸のイネに対する生理活性効果

Md-miR156ab and Md-miR395 Target WRKY Transcription Factors to Influence Apple Resistance to Leaf Spot Disease.

MicroRNAs (miRNAs) are key regulators of gene expression that post-transcriptionally regulate transcription factors involved in plant physiological activities. Little is known about the effects of miRNAs in disease resistance in apple (Malus×domestica). We globally profiled miRNAs in the apple cultivar Golden Delicious (GD) infected or not with the apple leaf spot fungus Alternaria alternaria f. sp. mali (ALT1), and identified 58 miRNAs that exhibited more than a 2-fold upregulation upon ALT1 infection. We identified a pair of miRNAs that target protein-coding genes involved in the defense response against fungal pathogens; Md-miR156ab targets a novel WRKY transcription factor, MdWRKYN1, which harbors a TIR and a WRKY domain. Md-miR395 targets another transcription factor, MdWRKY26, which contains two WRKY domains. Real-time PCR analysis showed that Md-miR156ab and Md-miR395 levels increased, while MdWRKYN1 and MdWRKY26 expression decreased in ALT1-inoculated GD leaves; furthermore, the overexpression of Md-miR156ab and Md-miR395 resulted in a significant reduction in MdWRKYN1 and MdWRKY26 expression. To investigate whether these miRNAs and their targets play a crucial role in plant defense, we overexpressed MdWRKYN1 or knocked down Md-miR156ab activity, which in both cases enhanced the disease resistance of the plants by upregulating the expression of the WRKY-regulated pathogenesis-related (PR) protein-encoding genes MdPR3-1, MdPR3-2, MdPR4, MdPR5, MdPR10-1, and MdPR10-2. In a similar analysis, we overexpressed MdWRKY26 or suppressed Md-miR395 activity, and found that many PR protein-encoding genes were also regulated by MdWRKY26. In GD, ALT-induced Md-miR156ab and Md-miR395 suppress MdWRKYN1 and MdWRKY26 expression, thereby decreasing the expression of some PR genes, and resulting in susceptibility to ALT1.

How can satellite imagery be used for mineral exploration in thick vegetation areas?

AbstractThe Hokuroku district, northern Japan, is globally recognized for rich ore deposits (kuroko and vein types), which have been thoroughly explored under thick vegetation cover. This situation is ideal to evaluate the effects of ore deposits on vegetation anomalies through geobotanical remote sensing. Here we present novel methods to detect vegetation anomalies caused by ore deposits and verify their usefulness by comparing the anomalies with a deposit potential map produced from multiple geological data. We use the reflectance spectra of Landsat ETM+ images acquired in summer and autumn to calculate a vegetation index for plant physiological activity. A key variable to detect the anomalies is a variation of vegetation index with time at each pixel. Difference in variation is enlarged by a sequence of image enhancement methods for the detection. We find that the vegetation anomalies, defined by the large ratios, correspond well to the high potential zones of ore deposits and known major deposits. Consequently, our methods can extend the applicability of remote sensing‐based mineral exploration to the areas covered by thick vegetation, in addition to traditional arid and semiarid areas.

Regulation of plants metabolism in response to salt stress: an omics approach

In recent era, some man-made and natural activities are responsible for causing salt stress that affects each component of environment. Among several components, plant is one of the essential components, and with the consequence of excess salts accumulation in the environment their metabolic activities may get affected. Plants exhibit hyper-osmotic stress and ion disturbance in the presence of excess salt accumulation. To combat this stress situation, some metabolites/or stress-responsive gene(s) and proteins are synthesized by the plants to mitigate the salt toxicity. Therefore, to reduce the impact of salt stress on yield and other physiological activities of plants it is essential to know the whole pathway through which plant’s metabolism get affected in the presence of salt. The present review is also dealing with the same objective and special focus is given to the omics tools, such as genomics, proteomics and metabolomics to discuss the different ways of tolerance mechanism in the plant system against salt toxicity.

盐旱复合胁迫对小麦幼苗生长和水分吸收的影响

盐旱复合胁迫对小麦幼苗生长和水分吸收的影响

Responses of plant calmodulin to endocytosis induced by rare earth elements

The wide application of rare earth elements (REEs) have led to their diffusion and accumulation in the environment. The activation of endocytosis is the primary response of plant cells to REEs. Calmodulin (CaM), as an important substance in calcium (Ca) signaling systems, regulating almost all of the physiological activities in plants, such as cellular metabolism, cell growth and division. However, the response of CaM to endocytosis activated by REEs remains unknown. By using immunofluorescence labeling and a confocal laser scanning microscope, we found that trivalent lanthanum [La(III)], an REE ion, affected the expression of CaM in endocytosis. Using circular dichroism, X-ray photoelectron spectroscopy and computer simulations, we demonstrated that a low concentration of La(III) could interact with extracellular CaM by electrostatic attraction and was then bound to two Ca-binding sites of CaM, making the molecular structure more compact and orderly, whereas a high concentration of La(III) could be coordinated with cytoplasmic CaM or bound to other Ca-binding sites, making the molecular structure more loose and disorderly. Our results provide a reference for revealing the action mechanisms of REEs in plant cells.

Plant Physiological Activity Sensing by Bioelectric Potential Measurement

Plant bioelectric potential response changes corresponding to the plant physiological activities. The activities and the growth of plant are influenced by the light irradiation conditions. In this study, we aim to obtain the relationship between the light irradiation conditions and the plant activity using plant bioelectric potential. We compared the characteristics of the bioelectric potential response and CO2 consumption rates at various light intensity rate of blue (470nm), green (525nm) and red lights (660 nm). These results showed that the difference in potential response has a similar trend with the change of CO2 consumption rate, and the trend depended on the light intensity rate of plural wavelengths. Strawberry is adopted as the sample plant.

黄土丘陵区土壤水分对黄刺玫叶片光响应特征参数的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 黄土丘陵区土壤水分对黄刺玫叶片光响应特征参数的影响 DOI: 10.5846/stxb201501310256 作者: 作者单位: 山东农业大学,山东农业大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点基础研究发展计划项目（2012CB416904） Effects of soil moisture on the photosynthetic light reaction of Rosa xanthina L. in a loess hilly region Author: Affiliation: Shandong Agricultural University,Shandong Agricultural 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:在半干旱黄土丘陵区，以3年生黄刺玫（Rosa xanthina L.）植株为材料，采用盆栽控水试验，利用CIRAS-2型便携式光合作用测定系统，在8个土壤水分含量下测定了黄刺玫叶片的光响应过程。探讨了黄刺玫光合生理参数与土壤水分的定量关系及土壤水分效应等级划分问题。结果表明：黄刺玫的净光合速率（Pn）、光合量子效率（Φ）、水分利用效率（WUE）、胞间CO2浓度（Ci）和蒸腾速率（Tr）对土壤水分都具有明显阈值响应特征。土壤相对含水量（RWC）在36.2%-81.2%范围内，黄刺玫在强光下的Pn和WUE水平较高，光合作用不会发生明显的光抑制。RWC为66.5%左右时，Φ与Pn达到最高水平，表现出较强的光能利用潜力；RWC为81.2%为时，Tr达最大值，RWC为44.5%时，WUE为最大值。依据黄刺玫叶片Pn、Ci、Tr和WUE与土壤水分的定量关系，确定RWC在低于36.2%时为"低产低效"等级，在36.2%-44.5%之间为"低产高效"等级，44.5%-66.5%为"高产高效"等级，66.5%-81.2%为"高产中效"等级，在高于81.2%时为"低产低效"等级。 Abstract:Water is a vital macronutrient and an important environmental factor, and is required for plants to conduct photosynthesis, which insufficient or excessive soil moisture will negatively affect. The soil water deficit is a key factor affecting plant physiological activity, restricting plant productivity and vegetative restoration. Rosa xanthina L. is one of the most widely distributed types of secondary vegetation in mountainous and hilly region in North China. Because of its high level of ecological adaptability, resistance to stress, and ecological functions, Rosa xanthina shows great potential value for development and application to the reconstruction of vegetation in the ecologically fragile Loess Plateau. Thus far, previous studies of Rosa xanthina have focused on such features as its root structure and soil reinforcement capabilities, the structure and ecological adaptations of its associated community, the morphology and anatomical structure of its leaves, and its photosynthetic characteristics. However, few studies have investigated the response relationship between photosynthesis and soil moisture, or the effective use of soil moisture by Rosa xanthina in arid habitats. The objectives of this study are to explore both the photosynthetic response to soil moisture and light and their quantitative relationship, and to attempt to identify the threshold effect of soil moisture on photosynthesis in Rosa xanthina L. In addition, this study aims to determine the species' photosynthetic productivity classification using physiological photosynthesis data. This new information will provide references that will help further our understanding of the water use and photophysiological characteristics of Rosa xanthina under drought stress. Three-year-old Rosa xanthina seedlings which were collected from the nursery and then potted in buckets were taken as materials in the semiarid loess hilly and gully regions. Sufficient water was provided to each seedling to saturate the soil in the bucket two days before the determination of photosynthetic parameters, and the soil water content was then monitored with no further watering. We measured soil water content and the photosynthetic parameters every two days until the seedlings withered. Using a CIRAS-2 portable photosynthesis system, the light reaction processes of Rosa xanthina plants were measured under eight soil moisture conditions found in the semiarid loess hilly region. The result showed that the net photosynthetic rate (Pn), quantum yield (Φ), and water use efficiency (WUE) exhibit clear threshold response characteristics. Higher photosynthetic rates (Pn) and WUE were observed in Rosa xanthina leaves when the relative soil water content (RWC) increased from 36.2% to 81.2%, and there was no significant photoinhibition of photosynthesis. When RWC was approximately 66.5%, Φ and Pn peaked, exhibiting strong potential energy utilization. The transpiration rate (Tr) and WUE peaked when RWC respectively were 81.2% and 44.5%. Based on the quantitative relationship between RWC and the plants' physiological photosynthetic characteristics, the RWC values measured when Pn, Φ, Tr, and WUE reached their respective maxima, and when RWC corresponded to the inflectional values of intercellular CO2 concentration (Ci) were designated as points of differentiation. Thus, we propose a metric for the grading of soil moisture availability according to its effect on Rosa xanthina photosynthesis. Soils with an RWC lower than 36.2% are considered "low productivity and low efficiency" grade, those with an RWC of 36.2%-44.5% are considered "low productivity and high efficiency" grade, those with an RWC of 44.5%-66.5% are considered "high productivity and high efficiency" grade, those with an RWC of 66.5%-81.2% are considered "high productivity and medium efficiency" grade, and those with an RWC greater than 81.2% are considered "low productivity and low efficiency" grade. 参考文献 相似文献 引证文献

Effect of irrigation regime on yield and yield components of soya bean

This study examines the effects of different irrigation regimes on seed yield and yield components of sprinkler-irrigated soya bean [(Glycine max (L.) Merr.] under field conditions in 2006, 2007 and 2008 in Zemun Polje (Srem, Srbija). Four irrigation regimes: 80-85% (T1), 70-75% (T2), 60-65% (T3) of field capacity, and non-irrigated regime (T0) were evaluated each experimental year. The experimental design was a randomised complete block with four replications on a Calcaric Chernozem. Water stress (drought) during growing season in the non-irrigated treatment (T0) decreased plant physiological activity, vegetative growth, and productivity of soya bean. Irrigation treatments significantly (P < 0.01) influenced soya bean seed yield and yield components. The treatment T2 produced higher seed yield than T1 and T3. Irrigation regimes had statistically significant different effects on yield components such as the plant height at harvest, number of pods per plant, number of seeds per plant, mass of pod with seeds per plant, 1,000 seed mass and hectoliter mass of soya bean seeds. Yield reduction was mainly due to a lower number of pods and seeds per plant and lower seed mass. The T1 treatment had the highest plant height of soya bean in all three growing years. The results have shown that under water scarcity, the treatment T3 is an acceptable irrigation strategy to stabilize and increase soya bean yield in Srem and neighboring countries in the region, provided that this practice is not prevented by economic constraints.