The Impact of Nitrogen-Fixing Bacteria, Iron, and Zinc Foliar Application on Dry Land Yellow Mustard (Brassica juncea) Grain and Oil Production

The study, conducted at the Research Farm of the College of Agriculture, University of Tabriz in 2021, focused on the effects of various nitrogen-fixing bacterial isolates, biofertilizers containing nitrogen and phosphorus, as well as iron and zinc foliar applications on mustard growth under rainfed conditions. The results indicated that biofertilizers, whether used alone or in combination with chemical fertilizers, produced comparable grain and oil outputs compared to chemical fertilizers alone. Additionally, the application of iron and zinc through foliar spraying significantly enhanced both grain and oil production. These findings suggest that integrating nitrogen-fixing bacteria and biofertilizers could reduce reliance on chemical nitrogenous fertilizers, leading to decreased production expenses, improved product quality, and minimized environmental impact. This study highlights the potential for sustainable agricultural practices in dry land farming as a viable alternative to traditional chemical-intensive methods. Substituting chemical nitrogenous fertilizers with nitrogen-fixing bacteria or biofertilizers could result in cost savings in mustard grain and oil production while promoting environmental sustainability.

C_4 plant species and geographical distribution in relation to climate in the desert vegetation of China

Water use efficiency of Ca plants is higher than that of C3 plants, and CAM （Crassulaceae Acid Metabolism） plants have the highest water use efficiency. In the desert regions of China, CAM plants are scarce, and C4 plants, especiaUy C4 woody plants, have an important position and role in the desert ecosystem. There are 45 species of Ca woody plants in the desert regions of China, including semi-woody plants, accounting for 6% of the total desert plant species in China, and most of them are concentrated in the families of Chenopodiaceae and Polygonaceae, which are 19 species and 26 species, respectively. The number of C4 herbaceous plants is 107 species, including 48 monocot species and 59 dicot species. C4 woody plants mainly inhabit the northwestem arid desert regions of China west of the Helan Mountains. The drought-resistance and drought-tolerance of Ca herbaceous plants are worse than C4 woody plants, and C4 herbaceous plants mainly inhabit areas with shallow groundwater depth and better water conditions in the desert regions, and are widely distributed along the margins of oases. The abundance of C4 woody plants is closely correlated with drought, but the abundance of C4 herbaceous plants increases with wet conditions.

Comparison of anatomical structure and photosynthetic characteristics between the two photosynthetic organs of the desert plant Hedysarum scoparium

The desert plant Hedysarum scoparium uses leaflets and rachises as its photosynthetic organs. The abundance of leaflets was lower under unfavorable environmental conditions and higher with improved water conditions. To examine the characteristics associated with the adaptation of H. scoparium to its environment, we selected plants with both compound leaves and rachis without leaflets to study the anatomical structures and gas exchange characteristics of the two organs. The results show that the water storage tissues in rachises were more developed compared with the leaflets. The diurnal courses of the net photosynthetic rate for the rachis and the leaflet were both in a bimodal pattern. Meanwhile, both two peak values of the rachis were significantly higher than those of the leaflet. The daily average transpiration rate was significantly higher in the rachis than in the leaflet in order to lower the temperature of the rachises. It was concluded that under desert drought conditions, the leaflets of H. scoparium were partially or completely degraded to reduce the transpiration area as an adaptive response to water deficit, and only the rachises were retained as photosynthetic organ. The rachises were found to be better suited to a desert habitat than the leaflets.

Essential oil yield and composition of four annual plants(ajowan,dill,moldavian balm and black cumin)under saline irrigation

Background:Ajowan,dill,moldavian balm and black cumin are annual medicinal plants,essential oil bearing that are cultivated in different parts of the world.Methods:A field experiment was conducted to assess the essential oil of ajowan,dill,moldavian balm and black cumin under salinity of 0.3,3,6 and 9 dS/m NaCl.Essential oils were obtained by using a Clevenger apparatus and their constituents were identified by GC and GC/MS.Results:Results showed that essential oil yield varied in tested plants under salt stress,but its changes did not follow a specific trend.Thymol was the most abundant constituent of ajowan seed essential oil,while thymol,γ-terpinene and p-cymene were the major constituents of the foliage essential oil of it.The most important component of dill seed essential oil was carvone and three main components of foliage essential oil were carvone,limonene andα-phellandrene.The essential oil component in moldavian balm mostly contained neral,geranial,geraniol,neryl acetate and geranyl acetate.The essential oil of black cumin was mainly composed of p-cymene under saline irrigation.Conclusion:The essential oil yield and compositions were affected by salt stress.The essential oil yield decreased because of decreasing dry biomass production.

Evolution of wheat architecture,physiology,and metabolism during domestication and further cultivation:Lessons for crop improvement

In recent decades,genetic advances in yield improvement in the major cereal crops,including wheat,has stagnated or proceeded at a slower rate than is required to meet future global food demand,particularly in the face of climate change.To reverse this situation,and in view of the future climate scenario,there is a need to increase the genetic diversity of wheat to increase its productivity,quality,stability,and adaptation to local agro-environments.The abundant genetic resources and literature are a basis for wheat improvement.However,many species,such as wild relatives,landraces,and old cultivars have not been studied beyond their agronomic characteristics,highlighting the lack of understanding of the physiological and metabolic processes(and their integration) associated with higher productivity and resilience in limiting environments.Retrospective studies using wheat ancestors and modern cultivars may identify novel traits that have not previously been considered,or have been underestimated,during domestication and breeding,but that may contribute to future food security.This review describes existing wheat genetic diversity and changes that occurred during domestication and breeding,and considers whether mining natural variation among wheat ancestors offers an opportunity to enhance wheat agronomic performance,spike architecture,canopy-and organ-level photosynthetic capacity,and responses to abiotic stress,as well as to develop new wheat hybrids.

Effects of drought stress on antioxidant enzyme,photosynthetic pigment and flavonoid pathway in two desert shrubs

Antioxidant enzyme activity, photosynthetic pigment content, and free malondialdehyde （MDA）, as well as flavonoid content and the key enzyme activity in the flavonoid pathway were determined in two desert shrubs, Caryopteris mongolica Bunge and Reaumuria soongorica （Pall.） Maxim. under drought stress. The free MDA content was enhanced during the experimental period, which may be an indicator of oxidative stress. Superoxide dismutase （SOD）, peroxidase （POD）, and ascorbate peroxidase （APX） activities in C. mongholica showed a significant increase during the experiment, but catalase （CAT） activity was slightly decreased. On the other hand, POD and APX activities showed a significant increase and SOD and CAT activity data had no significant changes in R. soongorica. APX, SOD, and CAT activities were higher in R. soongorica than in C. mongholica, but MDA content was lower, indicating that the lower values of MDA were attributed to higher activities of antioxidant enzyme in R. soongorica. Chlorophyll content decreased significantly in the two shrubs during the experiment, which indicated that there was a photoprotection mechanism through reducing light absorbance by decreasing pigments content. Caretonoids content increased in C. mongholica and decreased in R. soongorica. The ratio of Chla/Chlb decreased significantly but caretonoids/Chl revealed a significant increase in the two shrubs, which could be explained as no decrease of peripheral light-harvesting complexes and a higher tolerance to drought. Total flavonoid content and the activities of phenylalanine ammonialyase （PAL） and chalcone isomerase （CHI） showed different changes between C. mongholica and R. soongorica after treatment. These values decreased in R. soongorica and increased in C. mongholica except for PAL activity. However, anthocyanin content increased in the two shrubs, indicating that there was a different regulation response in the ftavonoid pathway in the two shrubs under drought stress, and anthocyanin should be an important antioxidant both in the shrubs. Our results demonstrated the different responses of antioxidant defense and drought tolerance ability between the two shrubs.

Effect of spatial scale and topography on spatial heterogeneity of soil seed banks under grazing disturbance in a sandy grassland of Horqin Sand Land, Northern China

Soil seed banks play an important role in the distribution and composition of plant communities in semiarid grassland ecosystems. However, information on how spatial scale influences the spatial heterogeneity of soil seed banks in a grassland under grazing disturbance is still lacking. Based on field sampling and greenhouse germination, we measured the species composition and seed density of soil seed banks at different spatial scales （30 mx30 m, 30 mx60 m and 30 mx90 m） along a topographical gradient in a sandy grassland in Horqin Sand Land, Northern China. By applying geostatistical methods, we examined how spatial scale and topography affected the spatial distribution of soil seed banks in the study area. Our results showed that the total number of species in soil seed banks, as well as the number of dominant annuals, increased with the increase of spatial scales. Seed density in soil seed banks decreased with the increase of spatial scales due to an increase in the slopes and relative heights of the sampling points. Geostatistical analysis showed that the relative structural variance （C/（C0＋C）） of seed density and species richness were over 65% for all spatial scales, indicating that these variables had an ob- vious spatial autocorrelation and the spatial structured variance accounted for the largest proportion of the total sample variance. Spatial autocorrelation of seed density in soil seed banks increased with the increase of measured scales, while that of species richness showed a reverse trend. These results suggest that the total number of spe- cies in soil seed banks is spatial scale dependent and lower topography may accommodate more seeds. Spatial distribution of seed density in soil seed banks is also scale dependent due to topographic variation. Grassland management, therefore, needs to consider local grazing disturbance regime, spatial scale and topography.

Chemical Screening of <i>Urochloa humidicola</i>: Methods for Characterizing Secondary Metabolites and Allelopathic Activity on Forage Legumes

The aim of this study was to identify the main classes of secondary metabolites present in the root and shoot crude extracts and fractions from the forage grass Urochloa humidicola (Rendle) Morrone & Zuloaga and to evaluate the allelopathic effect of these metabolites on forage legumes for intercropping. Phytochemical prospecting analyses, 1H NMR and capillary electrophoresis were performed on extracts of U. humidicola. Allelopathic activity was evaluated in germination of Stylosanthes, Macrotyloma axillare and Lactuca sativa L. (standard) in the presence of crude extracts, isolated saponins, flavonoids and trans-cinnamic acid. The metabolite classes present in the extracts could be determined by the combined use of the tested analytical techniques, but their use alone was usually not sufficient to chemically characterize the species. Capillary electrophoresis was effective in detecting phenolic compounds. Macrotyloma axillare was tolerant to crude extracts of U. humidicola. Saponins and trans-cinnamic acid, but not the flavonoids, reduced germination of the target plants.

Mesophyll thickness and sclerophylly among Calotropis procera morphotypes reveal water-saved adaptation to environments

Calotropis procera(Aiton)Dryand(Apocynaceae)is a native species in tropical and subtropical Africa and Asia.However,due to its fast growing and drought-tolerant,it has become an invasive species when it was introduced into Central and South America,as well as the Caribbean Islands.Currently,C.procera displays a wide distribution in the world.Invasiveness is important,in particular,because many invasive species exert a high reproductive pressure on the invaded communities or are highly productive in their new distributed areas.It has been suggested that a very deep root system and a high capacity to reduce stomatal conductance during water shortage could allow this species to maintain the water status required for a normal function.However,the true mechanism behind the successful distribution of C.procera across wet and dry environments is still unknown.C.procera leaves were collected from 12 natural populations in Brazil,Colombia and Mexico,ranging from wet to dry environments during 2014–2015.Many traits of morphology and anatomy from these distinct morphotypes were evaluated.We found that C.procera leaves had a considerable capacity to adjust their morphological,anatomical and physiological traits to different environments.The magnitude of acclimation responses,i.e.,plasticity,had been hypothesized to reflect the specialized adaptation of plant species to a particular environment.However,allometric models for leaf area(LA)estimation cannot be grouped as a single model.Leaves are narrower and thicker with low amounts of air spaces inside the leaf parenchyma in wet environments,while they are broader and thinner with a small number of palisade cell layers in dry environments.Based on these,we argue that broader and thinner leaves of C.procera dissipate incident energy at the expense of a higher rate of transpiration to survive in environments in which water is the most limiting factor and to compete in favorable wet environments.

Control of Plant Growth and Defense by Photoreceptors:From Mechanisms to Opportunities in Agriculture

Plants detect and respond to the proximity of competitors using light signals perceived by photoreceptor proteins.A low ratio of red to far-red radiation(R:FR ratio)is a key signal of competition that is sensed by the photoreceptor phytochrome B(phyB).Low R:FR ratios increase the synthesis of growth-related hormones,including auxin and gibberellins,promoting stem elongation and other shade-avoidance responses.Other photoreceptors that help plants to optimize their developmental configuration and resource allocation patterns in the canopy include blue light photoreceptors,such as cryptochromes and phototropins,and UV receptors,such as UVR8.All photoreceptors act by directly or indirectly controlling the activity of two major regulatory nodes for growth and development:the COP1/SPA ubiquitin E3 ligase complex and the PIF transcription factors.phyB is also an important modulator of hormonal pathways that regulate plant defense against herbivores and pathogens,including the jasmonic acid signaling pathway,In this Perspective,we discuss recent advances on the studies of the mechanisms that link photoreceptors with growth and defense.Understanding these mechanisms is important to provide a functional platform for breeding programs aimed at improving plant productivity,stress tolerance,and crop health in species of agronomic interest,and to manipulate the light environments in protected agriculture.

Illumina Sequencing Technology as a Method of Identifying T-DNA Insertion Loci in Activation- Tagged Arabidopsis thaliana Plants

Dear Editor, Forward genetic screens are commonly used as unbiased tools to isolate genes responsible for a phenotype of interest. In Arabidopsis thaliana, especially T-DNA activation tagging pop- ulations are frequently employed. These populations are gener- ated using vectors containing multiple copies of the constitutive 35S promoters derived from cau and often result in isolation i flower mosaic virus （35S CaMV） of dominant gain-of-function alleles （Weigel et al., 2000; Nakazawa et al., 2003）. This allows the study of members of large gene families that are often func- tionally redundant and, therefore, hard to identify in loss-of- function screens. Moreover, due to the dominant nature,

Evidence of functional and structural changes in the microbial community beneath a succulent invasive plant in coastal dunes

Coastal dunes represent priority habitats for conservation due to the provision of valuable ecosystem services such as land protection,water supply or biodiversity conservation.Soil microbial communities are of crucial importance to maintain plant diversity due to harsh environmental conditions,water limitation and nutrient scarcity.Invasive alien plants represent a major threat to ecosystem conservation.Here,we explored different impacts of Carpobrotus edulis,a succulent plant invading coastal areas worldwide,on the function and structure of bacterial communities.Sand represents a challenging substrate due to low organic matter content and limited microbial activity.We optimized bacterial extraction for functional evaluation before assessing ecosystem impacts produced by C.edulis.We compared 12 extracting procedures combining different soil storage,sample amount and extracting solutions on the functional activity of sand communities through the community-level physiological profile.We further explored the function(using Biolog Ecoplates)and structure[using polymerase chain reaction–denaturing gradient gel electrophoresis(PCR-DGGE)]of bacterial communities from dunes invaded by C.edulis.Saline solution consistently increased bacterial cells detected by cytometry(P≤0.001).Principal component analysis suggested a limited temporal framework(0–24 h)in which community function can be explored without significant alterations in C substrate consumption.Changes under C.edulis invasion exhibited a different pattern of C substrate utilization comparing native and non-native zones(interspecific),but also between native zones(intraspecific),suggesting that functional impacts are site-dependent.Complementary,results obtained from PCR-DGGE indicated that the bacterial community structure of native dunes significantly differed from dunes invaded by C.edulis.

基于不同养分策略的亚热带常绿与落叶树种的共存机制

常绿和落叶树种共存于中国东南部的亚热带森林中。为探究常绿和落叶树种应对亚热带磷限制所采用的碳获取策略,我们选取阳际峰常绿阔叶林中75种共存的木本植物,包括44种常绿树种和31种落叶树种,测定了其叶片的光合和呼吸速率,以及与碳(C)、氮(N)和磷(P)利用效率和再吸收效率的相关性状。落叶树种的光合氮利用效率(PNUE)、单位氮和磷的呼吸速率(R_(d,N)和R_(d,P))均显著高于常绿树种,但光合磷利用效率(PPUE)在二者之间无显著差异。对于任意给定的叶片P,常绿树种的碳利用效率(CUE)高于落叶树种。此外,落叶和常绿植物的氮再吸收效率(NRE)、磷再吸收效率(PRE)和N:P均无显著差异。这些结果表明,常绿树种维持高CUE使其在P限制的亚热带森林中成为优势树种。这些结果对其他生物群落中落叶和常绿物种的养分策略比较具有重要意义,也为未来的气候变化下的亚热带森林的群落动态建模提供了新见解。

Water stress resilient cereal crops:Lessons from wild relatives

Cereal crops are significant contributors to global diets.As climate change disrupts weather patterns and wreaks havoc on crops,the need for generating stress-resilient,high-yielding varieties is more urgent than ever.One extremely promising avenue in this regard is to exploit the tremendous genetic diversity expressed by the wild ancestors of current day crop species.These crop wild relatives thrive in a range of environments and accordingly often harbor an array of traits that allow them to do so.The identification and introgression of these traits into our staple cereal crops can lessen yield losses in stressful environments.In the last decades,a surge in extreme drought and flooding events have severely impacted cereal crop production.Climate models predict a persistence of this trend,thus reinforcing the need for research on water stress resilience.Here we review:(i)how water stress(drought and flooding)impacts crop performance;and(ii)how identification of tolerance traits and mechanisms from wild relatives of the main cereal crops,that is,rice,maize,wheat,and barley,can lead to improved survival and sustained yields in these crops under water stress conditions.

Shedding Light on Large-Scale Chromatin Reorganization in Arabidopsis thaliana

Plants need to respond quickly and appropriately to various types of light signals from the environment to optimize growth and development. The immediate response to shading, reduced photon flux （low light）, and changes in spectral quality involves changes in gene regulation. In the case of more persistent shade, the plant shows a dramatic change in the organization of chromatin. Both plant responses are controlled via photoreceptor signaling proteins. Re- cently, several studies have revealed similar features of chromatin reorganization in response to various abiotic and biotic signals, while others have unveiled intricate molecular networks of light signaling towards gene regulation. This opinion paper briefly describes the chromatin （de）compaction response from a light-signaling perspective to provide a link be- tween chromatin and the molecular network of photoreceptors and E3 ubiquitin ligase complexes.

Crop phenotyping in a context of global change:What to measure and how to do it

High-throughput crop phenotyping,particularly under field conditions,is nowadays perceived as a key factor limiting crop genetic advance.Phenotyping not only facilitates conventional breeding,but it is necessary to fully exploit the capabilities of molecular breeding,and it can be exploited to predict breeding targets for the years ahead at the regional level through more advanced simulation models and decision support systems.In terms of phenotyping,it is necessary to determined which selection traits are relevant in each situation,and which phenotyping tools/methods are available to assess such traits.Remote sensing methodologies are currently the most popular approaches,even when lab-based analyses are still relevant in many circumstances.On top of that,data processing and automation,together with machine learning/deep learning are contributing to the wide range of applications for phenotyping.This review addresses spectral and red-green-blue sensing as the most popular remote sensing approaches,alongside stable isotope composition as an example of a lab-based tool,and root phenotyping,which represents one of the frontiers for field phenotyping.Further,we consider the two most promising forms of aerial platforms(unmanned aerial vehicle and satellites)and some of the emerging data-processing techniques.The review includes three Boxes that examine specific case studies.

Hyperspectral reflectance-based phenotyping for quantitative genetics in crops: Progress and challenges

Many biochemical and physiological properties of plants that are of interest to breeders and geneticists have extremely low throughput and/or can only be measured destructively.This has limited the use of information on natural variation in nutrient and metabolite abundance,as well as photosynthetic capacity in quantitative genetic contexts where it is necessary to collect data from hundreds or thousands of plants.A number of recent studies have demonstrated the potential to estimate many of these traits from hyperspectral reflectance data,primarily in ecophysiological contexts.Here,we summarize recent advances in the use of hyperspectral reflectance data for plant phenotyping,and discuss both the potential benefits and remaining challenges to its application in plant genetics contexts.The performances of previously published models in estimating six traits fromhyperspectral reflectance data in maizewere evaluated on newsample datasets,and the resulting predicted trait values shown to be heritable(e.g.,explained by genetic factors)were estimated.The adoption of hyperspectral reflectance-based phenotyping beyond its current uses may accelerate the study of genes controlling natural variation in biochemical and physiological traits.

Beating the blues:engineering cryptochrome expression improves soybean yield

Phytochrome A overexpression can increase harvest index,as was shown 25 years ago in a breakthrough paper on tobacco(Robson et al.,1996).The impact of this important discovery has,however,not been fully developed.Plants at high densities often respond strongly to nearby competitors by strong elongation of their internodes and upward bending of their leaves,i.e.,shade avoidance.This is crucial for plants to ascertain access to sunlight,and this navigation through vegetation occurs through light cues that are sensed with various photoreceptors.A spectacular sensitivity is displayed by sun-loving plants that can already sense their nearby competitors even before mutual shading occurs and respond through a first acceleration of shoot elongation.This anticipatory response is triggered through red(R):far-red(FR)light-sensitive phytochrome photoreceptors that detect FR light that is reflected by nearby vegetation.When the vegetation continues to grow and true shading occurs,there is also a significant depletion of red and blue light,since the latter two are absorbed for photosynthesis in the overhead leaves(reviewed in Pierik and Ballaré,2021).Plants can respond to blue light depletion,especially when integrating it with signaling of FR enrichment in Arabidopsis(de Wit et al.,2016).