Young Roots Research Articles

Development of a dot blot macroarray and its use in gene expression marker-assisted selection for iron deficiency tolerant apple rootstocks

Iron deficiency chlorosis is a significant yield-limiting problem in apple production, and screening or breeding for iron deficiency tolerant rootstocks is one of the best solutions. To increase the efficiency of selection for iron deficiency tolerant hybrids, a reverse northern blot-based dot-blot macroarray protocol was established in this paper. Using this macroarray, the expression levels of MxHA7, MxFIT1, MxIRT1, MxCS1 and MxRD3 in young roots of 141 interspecific hybrids between Malus xiaojinensis and M. baccata were analyzed on the third day after low iron (4 μM) treatment. Assisted by these gene expression markers, 14 iron deficiency tolerant lines were preliminarily selected out of the 141 hybrids. Then, 12 (85.7 %) preliminarily selections were confirmed by the phenotypes validation on the iron deficiency chlorosis index. These results indicate that our dot-blot macroarray is suitable for gene expression marker-assisted breeding for low iron stress tolerant apple rootstocks.

Aktywność cytokininowa sześciu odmian Hordeum vulgare L. [Cytokinin activity of six cultivars of Hordeum vulgare L.

Cytokinin activity was determined in roots, crowns, ears of six varieties of the barley in the tobacco Wisconsin 38 callus tissue test. Analysis was made in early stage of ears. The order increasing values of the total cytokinin activity (the total activity of compounds fitting their mobility with zeatin, zeatin ribosid and their more polar derivatives) were for most part of varieties: younger roots < older roots < crowns < ears. Dependences between the cytokinin activity and fresh weight of analysed material were not found.

De Novo Assembly of the Pea (Pisum sativum L.) Nodule Transcriptome.

The large size and complexity of the garden pea (Pisum sativum L.) genome hamper its sequencing and the discovery of pea gene resources. Although transcriptome sequencing provides extensive information about expressed genes, some tissue-specific transcripts can only be identified from particular organs under appropriate conditions. In this study, we performed RNA sequencing of polyadenylated transcripts from young pea nodules and root tips on an Illumina GAIIx system, followed by de novo transcriptome assembly using the Trinity program. We obtained more than 58,000 and 37,000 contigs from “Nodules” and “Root Tips” assemblies, respectively. The quality of the assemblies was assessed by comparison with pea expressed sequence tags and transcriptome sequencing project data available from NCBI website. The “Nodules” assembly was compared with the “Root Tips” assembly and with pea transcriptome sequencing data from projects indicating tissue specificity. As a result, approximately 13,000 nodule-specific contigs were found and annotated by alignment to known plant protein-coding sequences and by Gene Ontology searching. Of these, 581 sequences were found to possess full CDSs and could thus be considered as novel nodule-specific transcripts of pea. The information about pea nodule-specific gene sequences can be applied for gene-based markers creation, polymorphism studies, and real-time PCR.

EFFECTS OF ORGANIC FERTILIZATION ON SOIL ORGANIC MATTER AND ROOT MORPHOLOGY AND DENSITY OF ORANGE TREES

The aim of this work was to verify the effect of organic fertilization on soil organic matter and on root apparatus of adult ‘Valencia late’ citrus trees [Citrus sinensis (L) Osbeck], grafted on C. aurantium L., in a citrus orchard (Sicily, Italy) organically managed from 15 years. In a randomized block experimental design, compost from pastazzo (a mixture of citrus pulp and peel), poultry manure, bovine manure, compared to a mineral fertilizer, was applied to the soil (455 g N/plant/year). For each plant, the same volume (0.022 m3) of soil was sampled at the same distance from the trunk for determination of root density (root weight/soil volume). Representative young roots were selected and analyzed by electron scanning microscopy (SEM). As far as soil characterization concerns, TOC, TEC, HA and FA were determined and then the related humufication parameters (HR% and DH%) were calculated. Results showed that organic fertilization, when compared to the mineral one, determines not only an improvement of soil organic matter humification, but also an increase of root biomass in citrus trees. The SEM analysis evidenced that organic fertilizers induce the appearance of adventitious buds on the terminal portions of the roots, a higher regularity of the elongating meristematic cells and, also, an increase of the production of root mucigel, thus improving their potential ability to up take nutrients from soil.

Technique to Obtain Mitotic Chromosomes of <i>Conyza bonariensis</i> L. Cronquist (Asteraceae)

Cytogenetic analysis requires cytological preparations that unequivocally reveal the chromosome number and permit optimal visualizations of chromosome morphology for the construction of karyotypes and ideograms. Chromosomal characterization is possible only by establishing these two parameters. To cytogenetically characterize the weed Conyza bonariensis (L.) Cronquist (Asteraceae), it was necessary to improve cytological analysis techniques to obtain optimal results. This species belongs to a genus whose plants have wide phenotypic plasticity. These plants can be morphologically differentiated by other types of analysis, and thus the application of this technique will serve as a reference for cytogenetical analysis of other groups of plants that have cytogenetic characteristics similar to those of C. bonariensis. The methodology described here highlights three main protocol steps: 1) root tip collection from newly germinated seed radicles and from young root tips of mature plants, 2) pretreatment of meristems with antimitotic agents, both isolated and combined, and 3) acid and enzymatic hydrolytic processes.

Colonization of Rice Roots by a Green Fluorescent Protein-Tagged Isolate of Ustilaginoidea virens

The fungus U. virens is the causal agent of rice false smut disease. The green fluorescent protein (GFP) was used to mark this fungus in order to visualize and analyze the colonization and infection processes in vivo. Using epifluorescence microscopy colonization and infection on rice roots were visualized in vivo. After inoculation for 2 to 15 d, it was observed that the conidia and their germ-tubes had penetrated into epidermis of young roots. The hyphae were found inside the root xylem 18 d after inoculation. Generally, the transformed fungus colonized the rhizosphere, the cortex as well as the vascular tissues with symptoms of root necrosis observed. The results of this work show that U. virens colonize not only rice panicles but also the roots.

Genotypic variations in root traits of wheat varieties at phytomer level

The aims of this study were to investigate genotypic variations in root traits at phytomer level of wheat varieties and for recommending a few root traits as selection parameters in future breeding programs. Two separate experiments were conducted to measure their root traits for hydroponically grown wheat plants. In Experiment 1, main axis length, root hair density and diameter differed from phytomer to phytomer at 60 days after sowing for two varieties, Shotabdi and Sonalika. Density of first order laterals at their axis of origin, dry weights of roots and shoots and root:shoot ratio varied significantly among 8 varieties. In Experiment 2, number of root bearing phytomer, total number of adventitious roots, main axis length at root bearing phytomer 1 and 2 (youngest roots were the reference point and numbered as phytomer 1), length of first order laterals at phytomer 3, root hair density and dry weights of roots and shoots were significantly different among varieties. PC1 (principal component 1) resulted in significant variation among varieties for number of live leaves, new roots appeared, number of root bearing phytomer, total number of adventitious roots, root dry weight and shoot dry weight. PC2 yielded significant difference among varieties for live leaves, main axes length at phytomer 1 & 2, number of new roots, root hair density and diameter. Selection of varieties based on main axes length at the youngest phytomer & root hair density per unit surface area along with dry weights of roots and shoots could be recommended for future breeding program as these four parameters consistently resulted in significant variation among varieties. DOI: http://dx.doi.org/10.3329/jbau.v12i1.21238 J. Bangladesh Agril. Univ. 12(1): 45-54, June 2014

Soybean actin, heat shock protein, and ribosomal protein promoters direct tissue-specific transgene expression in transgenic soybean

Soybean (Glycine max) promoters from an actin gene (GmActin), a ribosomal protein S11 gene (GmRpS11) and a heat shock protein 90 gene (GmHsp90), identified as being active during early induction of soybean somatic embryogenesis, were cloned, fused to the green fluorescence protein (gfp) gene and reintroduced into soybean for evaluation. All promoters displayed development- and tissue-specific regulation based on the expression of GFP in transgenic soybean. In seedlings, these three promoters gave rise to strong GFP expression in young roots, with very high levels of expression in the vascular tissues and root primordia. In older plants, promoter activity was observed in the vascular cambium of petioles, leaf midribs, and in the mesophyll of expanding leaves, but at reduced levels. The GmActin promoter gave very high GFP expression in developing and mature seeds. All three promoters displayed high activity following induction of somatic embryogenesis from immature soybean cotyledons. Comparison of promoter-regulated GFP transgene expression with transcriptome analysis using RNA-Seq revealed agreement in expression intensity in roots, leaves, and flowers but exceptions for expression in young developing seeds. Evaluation of specific promoters in transgenic plants is needed for proper elucidation of promoter-regulated transgene activity.

Anatomía de los órganos vegetativos de dos especies de Atriplex (Chenopodiaceae) que crecen en Venezuela

In Venezuela, Atriplex is represented by A. cristata and A. oestophora, the latter being endemic; they inhabit coastal areas with high temperatures, high solar radiation and sandy soils with high salt content. This work aimed to provide information to facilitate and clarify these species taxonomic delimitation, throughout the study of the anatomy of their vegetative organs; this may also clarify our understanding of their adaptability to soil and climatic conditions prevailing in areas they inhabit. The plant material was collected from at least three individuals of each species in Punta Taima Taima and Capatárida, Falcon. Segments of roots, located near the neck and towards the apex, apical, middle and basal internodes of stems, were taken; and of leaves, located in the middle portion of plants. This material was fixed in FAA (formaldehyde, acetic acid, 70% ethanol) until processing. Semipermanent and permanent microscope slides were prepared with transverse or longitudinal sections, made using a razor (free-hand) or a rotation microtome, in this latter case, after paraffin embedding; besides, additional plates were mounted with portions of leaf epidermis, obtained by the maceration technique. The sections were stained with aqueous toluidine blue (1%) or safranin-fast-green, and mounted in water-glycerin or in Canada balsam. In order to calculate the vulnerability index, the vessel diameter in the vascular rings of roots, as well as their density, were quantified. Our results revealed structural features in the different organs, that resulted of taxonomic value and allowed the distinction of the species: in the leaf, the presence of aquifer tissue, the number of vascular bundles and their organization in the midrib, and the collenchyma differentiation in this part of the leaf; in the roots, the xylem and phloem arrangement in the growth rings, the nature of conjunctive tissue, and the presence of included phloem in one species. In addition, the species showed typical anatomical features of halophytes and xerophytes, such as: high density of trichomes on leaves and young stems which act as salt secreting glands, abundant sclerenchyma in stems and roots, water storage tissue and Kranz anatomy in leaves, narrow cortical region in young roots, presence of cambial variants in stems and roots, as well as short and narrow xylem vessels. Vulnerability index calculations indicated that both species tend to assure conduction but not the efficiency of the system. Atriplex species have anatomical characters which facilitate their adaptation to the special conditions prevailing in their habitats and that may be used for taxonomic delimitation.

Identification and use of the sugarcane bacilliform virus enhancer in transgenic maize.

BackgroundTranscriptional enhancers are able to increase transcription from heterologous promoters when placed upstream, downstream and in either orientation, relative to the promoter. Transcriptional enhancers have been used to enhance expression of specific promoters in transgenic plants and in activation tagging studies to help elucidate gene function.ResultsA transcriptional enhancer from the Sugarcane Bacilliform Virus - Ireng Maleng isolate (SCBV-IM) that can cause increased transcription when integrated into the the genome near maize genes has been identified. In transgenic maize, the SCBV-IM promoter was shown to be comparable in strength to the maize ubiquitin 1 promoter in young leaf and root tissues. The promoter was dissected to identify sequences that confer high activity in transient assays. Enhancer sequences were identified and shown to increase the activity of a heterologous truncated promoter. These enhancer sequences were shown to be more active when arrayed in 4 copy arrays than in 1 or 2 copy arrays. When the enhancer array was transformed into maize plants it caused an increase in accumulation of transcripts of genes near the site of integration in the genome.ConclusionsThe SCBV-IM enhancer can activate transcription upstream or downstream of genes and in either orientation. It may be a useful tool to activate enhance from specific promoters or in activation tagging.

Mechanisms for tolerance of very high tissue phosphorus concentrations in Ptilotus polystachyus.

Study of plants with unusual phosphorus (P) physiology may assist development of more P-efficient crops. Ptilotus polystachyus grows well at high P supply, when shoot P concentrations ([P]) may exceed 40 mg P g(-1) dry matter (DM). We explored the P physiology of P. polystachyus seedlings grown in nutrient solution with 0-5 mM P. In addition, young leaves and roots of soil-grown plants were used for cryo-scanning electron microscopy and X-ray microanalysis. No P-toxicity symptoms were observed, even at 5 mM P in solution. Shoot DM was similar at 0.1 and 1.0 mM P in solution, but was ∼14% lower at 2 and 5 mM P. At 1 mM P, [P] was 36, 18, 14 and 11 mg P g(-1) DM in mature leaves, young leaves, stems and roots, respectively. Leaf potassium, calcium and magnesium concentrations increased with increasing P supply. Leaf epidermal and palisade mesophyll cells had similar [P]. The root epidermis and most cortical cells had senesced, even in young roots. We conclude that preferential accumulation of P in mature leaves, accumulation of balancing cations and uniform distribution of P across leaf cell types allow P. polystachyus to tolerate very high leaf [P].

Effect of parameter choice in root water uptake models – the arrangement of root hydraulic properties within the root architecture affects dynamics and efficiency of root water uptake

Abstract. Detailed three-dimensional models of root water uptake have become increasingly popular for investigating the process of root water uptake. However, they suffer from a lack of information on important parameters, particularly on the spatial distribution of root axial and radial conductivities, which vary greatly along a root system. In this paper we explore how the arrangement of those root hydraulic properties and branching within the root system affects modelled uptake dynamics, xylem water potential and the efficiency of root water uptake. We first apply a simple model to illustrate the mechanisms at the scale of single roots. By using two efficiency indices based on (i) the collar xylem potential ("effort") and (ii) the integral amount of unstressed root water uptake ("water yield"), we show that an optimal root length emerges, depending on the ratio between roots axial and radial conductivity. Young roots with high capacity for radial uptake are only efficient when they are short. Branching, in combination with mature transport roots, enables soil exploration and substantially increases active young root length at low collar potentials. Second, we investigate how this shapes uptake dynamics at the plant scale using a comprehensive three-dimensional root water uptake model. Plant-scale dynamics, such as the average uptake depth of entire root systems, were only minimally influenced by the hydraulic parameterization. However, other factors such as hydraulic redistribution, collar potential, internal redistribution patterns and instantaneous uptake depth depended strongly on the arrangement on the arrangement of root hydraulic properties. Root systems were most efficient when assembled of different root types, allowing for separation of root function in uptake (numerous short apical young roots) and transport (longer mature roots). Modelling results became similar when this heterogeneity was accounted for to some degree (i.e. if the root systems contained between 40 and 80% of young uptake roots). The average collar potential was cut to half and unstressed transpiration increased by up to 25% in composed root systems, compared to homogenous ones. Also, the least efficient root system (homogenous young root system) was characterized by excessive bleeding (hydraulic lift), which seemed to be an artifact of the parameterization. We conclude that heterogeneity of root hydraulic properties is a critical component for efficient root systems that needs to be accounted for in complex three-dimensional root water uptake models.

Computed tomography coronary angiography should be performed in all patients with Marfan Syndrome prior to aortic root replacement

Dear Editor,Aortic dissection is the most common cause of death in the naturalhistory of patients with Marfan Syndrome [1]. To prevent death due toacute aortic dissection, indications for aortic root replacement are muchless restrictive in patients with Marfan Syndrome, compared to the gen-eral population [2,3]. The number of young Marfan patients undergoingaortic root surgery is steadily increasing [4]. With increasing numbers ofpatients in the operating theater comes an increasing prevalence ofperi-operative complications.In our clinic, three patients with Marfan Syndrome who had toundergo aortic root replacement were diagnosed with an aberrantcoronary artery, of whom only one pre-operatively. All three patientsunderwent aortic root replacement for progressive aortic root dilata-tion;withamaximumdiameterof50mm.Noneofthepatientsexperi-encedanycardiaccomplaints.Atthetimeofsurgery,twopatientswereon β-blockade, oneincombination withanangiotensin II (AT II)recep-tor blocker, and one patient was not on any medication, as β-blockadewas poorly tolerated, and the beneficial effects of ACE inhibitors andAT II receptor blockers had not yet been proven at the time. In allthree patients the ramus circumflexus (RCX) was found to arise fromthe right coronary artery (RCA).In patient A (male, 28 years old, surgery in 2008), the aberrantcoronary artery was diagnosed on transesophageal echocardiographyintheoperatingtheaterunderanesthesia(Fig.1A).Surgerywasabortedto perform computed tomography (CT) coronary angiography, afterwhichasuccessfulDavidprocedurewasperformed.Thebuttonholdingboth the RCA and the RCX was re-implanted in the commissurebetween the right- and the non-coronary cusps without complication.In patient B (female, 43 years old, surgery in 2009), the aberrant coro-nary artery had not been diagnosed pre-operatively, and was uninten-tionally sliced during surgical dissection of the right coronary button.Fortunately, the RCX could successfully be re-implanted at the locationof the non-coronary cusp. In retrospect, pre-operative transesophagealechocardiographydidrevealtheaberrantRCX,buthadbeenoverlooked(Fig. 1B). To prevent such major complications during future surgery,we introduced CT coronary angiography in all Marfan patients prior toaortic surgery. Therefore, in patient C (male, 31 years old, surgery in2013),anaberrant RCX arisingfromthe RCAwasfound on CT coronaryangiographypriortosurgery(Fig.2).Inthispatient,aorticrootreplace-mentwassuccessfullyperformed,withre-implantationofthecoronaryarteries.In the general population, about 1.1% of individuals have an aberrantcoronary artery [5]. These numbers could somewhat underestimate thereal prevalence, as malign coronary anatomy may result in suddencardiac death prior to diagnosis. Our population consisted of 54 patientswho underwent surgery between 2003 and 2013, in which threepatients (5.6%, CI 95% −0.6% to 11.8%) were diagnosed with an aberrantcoronary artery. This higher percentage could well be incidental, asabsolute patient numbers are small. Currently, no data have been pub-lishedindicatingthatpatientswithMarfanSyndromehaveahigherprev-alence of aberrant coronary anatomy. On the other hand, the chance of aMarfan patient undergoing aortic surgery during his/her lifetime is muchgreater than in the general population, increasing the relative risk to en-counter coronary anomalies in these patients.Current European guidelines recommend cardiovascularmagnetic resonance (CMR) in all Marfanpatients to evaluate the entireaorta.Moreover,ifevaluationofcoronaryarterydiseasepriortosurgeryis warranted, CT coronary angiography is recommended, as catheter

Transcriptomic complexity in young maize primary roots in response to low water potentials.

BackgroundWidespread and more frequently occurring drought conditions are a consequence of global warming and increase the demand for tolerant crop varieties to feed the growing world population. A better understanding of the molecular mechanisms underlying the water deficit response of crops will enable targeted breeding strategies to develop robust cultivars.ResultsIn the present study, the transcriptional response of maize (Zea mays L.) primary roots to low water potentials was monitored by RNA sequencing (RNA-Seq) experiments. After 6 h and 24 h of mild (-0.2 MPa) and severe (-0.8 MPa) water deficit conditions, the primary root transcriptomes of seedlings grown under water deficit and control conditions were compared. The number of responsive genes was dependent on and increased with intensification of water deficit treatment. After short-term mild and severe water deficit 249 and 3,000 genes were differentially expressed, respectively. After a 24 h treatment the number of affected genes increased to 7,267 and 12,838 for mild and severe water deficit, respectively, including more than 80% of the short-term responsive genes. About half of the differentially expressed genes were up-regulated and maximal fold-changes increased with treatment intensity to more than 300-fold. A consensus set of 53 genes was differentially regulated independently of the nature of deficit treatment. Characterization revealed an overrepresentation of the Gene Ontology (GO) categories “oxidoreductase activity” and “heme binding” among regulated genes connecting the water deficit response to ROS metabolism.ConclusionThis study gives a comprehensive insight in water deficit responsive genes in young maize primary roots and provides a set of candidate genes that merit further genetic analyses in the future.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-741) contains supplementary material, which is available to authorized users.

Arabidopsis thaliana Phosphoinositide-Specific Phospholipase C Isoform 3 (AtPLC3) and AtPLC9 have an Additive Effect on Thermotolerance

The heat stress response is an important adaptation, enabling plants to survive challenging environmental conditions. Our previous work demonstrated that Arabidopsis thaliana Phosphoinositide-Specific Phospholipase C Isoform 9 (AtPLC9) plays an important role in thermotolerance. During prolonged heat treatment, mutants of AtPLC3 showed decreased heat resistance. We observed no obvious phenotypic differences between plc3 mutants and wild type (WT) seedlings under normal growth conditions, but after heat shock, the plc3 seedlings displayed a decline in thermotolerance compared with WT, and also showed a 40-50% decrease in survival rate and chlorophyll contents. Expression of AtPLC3 in plc3 mutants rescued the heat-sensitive phenotype; the AtPLC3-overexpressing lines also exhibited much higher heat resistance than WT and vector-only controls. The double mutants of plc3 and plc9 displayed increased sensitivity to heat stress, compared with either single mutant. In transgenic lines containing a AtPLC3:GUS promoter fusion, GUS staining showed that AtPLC3 expresses in all tissues, except anthers and young root tips. Using the Ca(2+)-sensitive fluorescent probe Fluo-3/AM and aequorin reconstitution, we showed that plc3 mutants show a reduction in the heat-induced Ca(2+) increase. The expression of HSP genes (HSP18.2, HSP25.3, HSP70-1 and HSP83) was down-regulated in plc3 mutants and up-regulated in AtPLC3-overexpressing lines after heat shock. These results indicated that AtPLC3 also plays a role in thermotolerance in Arabidopsis, and that AtPLC3 and AtPLC9 function additionally to each other.

Secondary Metabolite Content in Roots and Callus of Paeonia Anomala L.

Taking into account the fact that in the process of introduction in vitro culture the change of secondary metabolite content may take place we compared the chemical composition of plant material of wild-growing plants of Paeonia anomala introduced and produced using the methods of clonal micropropagation, callus tissue.The content of phenolic compounds, that is catechins and gallatos was compared. Paeoniflorin content was estimated by direct spectrophotometry of methanol extracts (λ = 231,7 nm, e 1% 1 sm = 265.4). Integral characteristic of the obtained extracts was received by comparison of absorption spectra using spectrophotometer SP - 121 within wave diapason 300 - 460 nm.Light absorption curves of methanol extracts had two distinct peaks at λ = 232 nm and λ = 275 nm typical of paeoniflorin. Paeoniflorin content was 80 % higher in young peony roots than in control plant. This glycoside content in callus culture was 44 % higher than in wild-growing plant roots and 26 % lower than in plantlet roots.The use of ethanol as extragent showed a higher content of extracted substances in callus tissue. The comparison of the obtained spectra in the region corresponding to phenolic compound absorption shows the highest phenolic compound content in callus tissue and young plant roots. Judging by light absorption maximum it may be phenolic acids. The lowest phenolic compound content was determined in adult wild-growing plant roots, where a high phlobaphene content was visually observed.The conducted research confirms the fact that callus culture of Paeonia anomala L. is a perspective producer of monoterpene glycosides and phenolic compounds. Extracts from plantlets and callus culture exceed in biological active substance content rootstock extracts of open air plants.

Root and rhizosphere processes-high time to dig deeper.

Root and rhizosphere processes-high time to dig deeper.

Identification and functional analysis of BABY BOOM genes from Rosa canina

BABY BOOM (BBM), initially identified in Brassica napus, can enhance the shoot regeneration capacity in tissue culture and is involved in the conversion from the vegetative to embryogenic state. This study aimed to isolate BBM orthologue genes from Rosa canina and analyse their functions. Two full-length cDNAs, designated RcBBM1 and RcBBM2, were isolated from R. canina by the rapid amplification of cDNA ends (RACE). The predicted amino acid sequences of the two RcBBMs contained the bbm-1 motif and the motifs typically conserved in the eudicotANT (euANT) lineage. Phylogenetic tree analysis showed that the RcBBMs were most closely related to the BBM orthologue genes identified in Glycine max and Medicago truncatula. The transcripts of the RcBBMs were detected in young roots, calluses, and protocorm-like bodies (PLBs), whereas they were undetectable in stems, leaves, and flowers. RcBBM1-GFP and RcBBM2-GFP fusion proteins were both localized in the nucleus. 35S::RcBBM1 and 35S::RcBBM2 transgenic Arabidopsis thaliana lines exhibited enhanced shoot regeneration capacity in tissue culture, but did not undergo spontaneous somatic embryogenesis. The results suggest that RcBBMs may be candidate genes for improving the shoot regeneration efficiency of R. canina.

Root anatomical phenes associated with water acquisition from drying soil: targets for crop improvement.

Several root anatomical phenes affect water acquisition from drying soil, and may therefore have utility in breeding more drought-tolerant crops. Anatomical phenes that reduce the metabolic cost of the root cortex ('cortical burden') improve soil exploration and therefore water acquisition from drying soil. The best evidence for this is for root cortical aerenchyma; cortical cell file number and cortical senescence may also be useful in this context. Variation in the number and diameter of xylem vessels strongly affects axial water conductance. Reduced axial conductance may be useful in conserving soil water so that a crop may complete its life cycle under terminal drought. Variation in the suberization and lignification of the endodermis and exodermis affects radial water conductance, and may therefore be important in reducing water loss from mature roots into dry soil. Rhizosheaths may protect the water status of young root tissue. Root hairs and larger diameter root tips improve root penetration of hard, drying soil. Many of these phenes show substantial genotypic variation. The utility of these phenes for water acquisition has only rarely been validated, and may have strong interactions with the spatiotemporal dynamics of soil water availability, and with root architecture and other aspects of the root phenotype. This complexity calls for structural-functional plant modelling and 3D imaging methods. Root anatomical phenes represent a promising yet underexplored and untapped source of crop breeding targets.

Variations in phytochemicals, proximate and nutrient constituents of Trichosanthes cucumerina L. plant (804.32)

Trichosanthes cucumerina L. is used for food and medicine. In this study, the young and old T. Cucumerina seeds, leaves, fruits and roots (dried powder) were analysed for phytochemicals, proximate and nutrient constituents using chemical tests and standard spectrophotometric methods. Phytochemical qualitative analysis revealed the absence of cardiac glycosides, and saponin in all plant parts while tannins and phenols were present only in old leaves and terpenoids in young and old seeds and roots. Phlobatanin is not contained in young fruit and seeds but present in other parts. Steroids, flavonoids, alkaloids and reducing sugar were found to be major phytochemicals in all plant parts and their levels increased significantly (P < 0.05) in T. cucumerina old parts. The young and old parts of T. cucumerina variant contain varying concentration of nutrients. Calcium ranged from 13.05 to 152.41 mg/100 g with a mean of 88.26 mg/100 g, potassium (13.20‐26.60, mean = 23.32 mg/100 g), magnesium (30.28‐50.10, mean = 39 mg/100 g), sodium (3.45‐52.25, mean = 22.9 mg/100 g and iron (10.40‐65.50, mean = 32.96 mg/100 g) were the most abundant. Proximate of all parts showed a high moisture content (mean =71.8 %) except in roots and old seeds contained high crude fats (mean = 15.75 %). The study has revealed the T. Cucumerina variant has useful nutrients and flavonoids and can be utilized as sources of minerals and antioxidants respectively.