Leaf Architecture Research Articles

Saportaea Fontaine et White 1880 – An enigmatic, long-ranging, widely distributed but rare type of late Paleozoic and early Mesozoic foliage

New material of the enigmatic plant Saportaea salisburioides Fontaine et White 1880 is described from three localities in the late Permian Umm Irna Formation from the Dead Sea region, Jordan. The preservation and the sedimentology indicate that remains from all three localities were transported over a very short distance. In one of the localities the rich leaf association exclusively comprises Saportaea remains, which show a remarkably large morphological variation. They occur together with a coaly axis with attached petioles and several isolated petioles. The specimens apparently belonged to a single monospecific stand, or maybe even a single plant. Another locality yielded a large leaf portion showing the leaf architecture. Our material leads to the conclusion that Saportaea grandifolia Fontaine et White 1880 and Baiera virginiana Fontaine et White 1880 are to be regarded as synonyms of S. salisburioides. In one locality Saportaea foliage was found in close association with Nystroemia sp., which might suggest that this fructification belongs to Saportaea. Saportaea is a long-ranging, geographically widely distributed but very rare genus that first appears in the Westphalian D (Moscovian, Pennsylvanian) and has its last occurrence in the Carnian (Late Triassic).

Simulated herbicide spray retention on floating aquatic plants as affected by carrier volume and adjuvant type

AbstractFoliar delivery of herbicides is a common means for plant management in aquatic environments. Though this technique is decades old, little is known about vegetative spray retention relative to this application method. A more complete understanding of maximizing herbicide retention could lead to improved plant management while simultaneously decreasing pesticide load in aquatic environments. Therefore outdoor mesocosm experiments were conducted in 2020 to evaluate the effect of adjuvant type on foliar spray retention in waterhyacinth [Eichhornia crassipes (Mart.) Solms]. Additionally, the effect of carrier volume on spray retention in waterhyacinth, waterlettuce (Pistia stratiotes L.), and giant salvinia (Salvinia molesta D.S. Mitchell) was documented. Spray deposition did not differ among the nine adjuvants tested; however, spray retention was reduced 6% to 11% when an adjuvant was excluded from the spray solution. The effect of carrier volume on spray retention in waterhyacinth, waterlettuce, and giant salvinia was also investigated. Decreases in spray retention were most sensitive to increased carrier volume in waterhyacinth, followed by giant salvinia and waterlettuce. Among species, spray retention potential, as determined by intercept estimates, was greatest in waterlettuce and giant salvinia regardless of carrier volume. Asymptotes estimates for waterhyacinth, waterlettuce, and giant salvinia were 33%, 46%, and 79% spray retention, respectively. In other words, spray retention was the lowest and remained relatively constant at these values for the high carrier volumes tested (935 and 1,870 L ha−1), which were likely due to the presence of pubescence on leaves and flatter leaf architecture represented by waterlettuce and giant salvinia compared to the glabrous vertical leaves of waterhyacinth. Future research will evaluate these concepts under field conditions.

A eudicot leaf from the Lower Cretaceous (Aptian, Araripe Basin) Crato Konservat-Lagerstätte.

The Crato Konservat-Lagerstätte in Brazil preserves an exceptionally rich assemblage of plant macrofossils from the Early Cretaceous (late Aptian), including rare early angiosperm fossils related to Nymphaeales, monocots, and magnoliids, and a variety of angiosperms of uncertain affinities. Macrofossils of eudicot angiosperms have not been described previously, despite the presence of tricolpate pollen. We describe a fossil leaf with morphology characteristic of eudicot angiosperms. The fossil was collected from a quarry in the Lower Cretaceous (late Aptian) Crato Formation of northeastern Brazil in the state of Ceará. We compared the leaf architecture with that of ferns, gymnosperms, and similar living and fossil angiosperms. The leaf of Baderadea pinnatissecta gen. et sp. nov. is simple and petiolate, with leaf architecture similar to that of some herbaceous Ranunculales. The blade is 5 cm long and the margin is untoothed and twice pinnately lobed with narrow lobes (pinnatisect). The primary vein framework is pinnate and there are multiple orders of reticulate venation. The combination of characters preserved in the fossil supports the interpretation that B. pinnatissecta was an herbaceous eudicot similar to some members of Ranunculales and distinguished from other lobate Aptian angiosperms by leaf shape, presence of multiple orders of reticulate venation, and the absence of glandular teeth. The presence of eudicots in the flora of the Crato was already supported by pollen; the discovery of macrofossils like these provides additional information about their morphology and ecological role in low-latitude Early Cretaceous plant communities.

Maize yield performance altered by trinexapac-ethyl rates and plant population

Increases in plant density associated with the use of plant growth regulators, aside from modifying the plant architecture, can also change the maize yield performance. This study aims to investigate the yield components and grain yield of maize hybrids with contrasting leaf architecture, in response to different plant populations and trinexapac-ethyl rates (TE). Field experiments were conducted in two growing seasons, in a (5 x 5) factorial randomized block design. The treatments consisted of: five plant population (40, 60, 80, 100, and 120 thousand plants ha-1) and five TE rates (0, 100, 200, 300, and 400 g a.i. ha-1), with four replications, using the hybrids 2B710 HX and Status TL. We evaluated the number of rows per ear, ear length, number of grains per row, 1000-grain mass, and yield. An increased plant density reduces ear length, number of grains per row and 1000-grain mass, without changing the number of grain rows per ear. TE rates increases ear length and number of grains per row and reduces 1000-grain mass, mainly under favorable cultivation conditions. TE interacts with the plant density, changing the maize yield components with increases in grain yield, but these gains variy, according to the environment and genotype characteristics.

Genome-wide markers for seed yield and disease resistance in perennial ryegrass

The market success of perennial ryegrass (Lolium perenne L.) cultivars depends on sufficient seed production, as they are propagated by seed. However, breeding for high quality forage production reduces seed yield, and breaking the negative correlation would help to overcome the problem. The foliar disease crown rust is another factor affecting reproductive capacity and thereby seed yield. We evaluated seed yield-related traits and resistance to crown rust in a collection of commercial cultivars and ecotypes of perennial ryegrass and identified genome-wide markers associated with the traits. The study revealed high variation between the ecotype and cultivar groups as well as between years. A genome-wide association study identified 17 DNA single-nucleotide polymorphisms (SNPs) of which eight were associated with crown rust and nine with flag-leaf length. The SNP markers were located within or near predicted genes functioning in defense against pathogens. The identified genes are strong candidates for a further in-depth functional study to continue unravel determination of leaf architecture and crown rust resistance in perennial ryegrass.

Comparative profiling of genome-wide small RNAs in non-heading Chinese cabbage [Brassica rapa subsp. chinensis (L.) Hanelt

Non-heading Chinese cabbage is characterized with diversity of leaf shape and of leaf architecture. Small RNAs are broadly involved in leaf development. To understand how small RNAs regulated leaf shape and leaf architecture, we choose two representative genotypes of non-heading Chinese cabbage (Brassica. rapa ssp. chinensis cv Wut) with distinct leaf shapes, and performed small RNA deep sequencing. Huaq, a genotype with long blades and wide petioles, generated 13.30 million small RNA reads while Wut, a genotype with round blades and long petioles, produced 14.69 million. After normalizing to RP10M, they share 0.5 million small RNAs with about 4 million reads which are mapping to the genome. Four types of small RNAs were selected from the libraries: miRNAs, ta-siRNAs, mRNA-derived siRNAs and rasiRNAs. 45 miRNA members among 75 display different expressional level such as miR166 and miR319, which play important role in leaf development. It indicated the different leaf phenotype between Huaq and Wut that possibly regulated by miRNA dosage. One of the small RNAs originated from TAS3 is Huaq dominant. About 2 thousand small RNAs derived from genes were expressionally different between genotypes, and some of them derived from antisense chains of genes. Chloroplast derived small RNAs were found that Wut were more than Huaq, which is consistent with its greener leaves. Comparative analysis of small RNAs on genome-wide level will broaden our view of molecular events underling diversity of leaf shape and architecture.

Active suppression of leaflet emergence as a mechanism of simple leaf development

Angiosperm leaves show extensive shape diversity and are broadly divided into two forms; simple leaves with intact lamina and compound leaves with lamina dissected into leaflets. The mechanistic basis of margin dissection and leaflet initiation has been inferred primarily by analysing compound-leaf architecture, and thus whether the intact lamina of simple leaves has the potential to initiate leaflets upon endogenous gene inactivation remains unclear. Here, we show that the CINCINNATA-like TEOSINTE BRANCHED1, CYCLOIDEA, PROLIFERATING CELL FACTORS (CIN-TCP) transcription factors activate the class II KNOTTED1-LIKE (KNOX-II) genes and the CIN-TCP and KNOX-II proteins together redundantly suppress leaflet initiation in simple leaves. Simultaneous downregulation of CIN-TCP and KNOX-II in Arabidopsis leads to the reactivation of the stemness genes KNOX-I and CUPSHAPED COTYLEDON (CUC) and triggers ectopic organogenesis, eventually converting the simple lamina to a super-compound form that appears to initiate leaflets indefinitely. Thus, a conserved developmental mechanism promotes simple leaf architecture in which CIN-TCP-KNOX-II forms a strong differentiation module that suppresses the KNOX-I-CUC network and leaflet initiation.

Times of Trinexapac-ethyl application associated to plant densities in agronomic performance of second-season corn

Plant growth regulators, which can alter the plant size and anatomy, allow the use of cultivars of interest that do not have a modern leaf architecture, making higher plant densities possible. The objective of this study was to evaluate the agronomic performance of second season corn, grown at different plant densities and under Trinexapac-ethyl applications at different stages of crop development. The field study was carried out in two growing seasons (2013 and 2014), at the Fazenda Escola of the State University of Londrina. Fifteen treatments were evaluated in a randomized block, 5 x 3 factorial design, at five plant densities (40,000, 60,000, 80,000, 100,000 and 120,000 plants per hectare), of Trinexapac-ethyl applied in three stages: control (no application), V6 and V9, with four replications. The morphological plant characteristics, the yield components and grain yield were evaluated. Increases in plant density raise the plant height, reduce the number of grains per ear, ear length and 100-kernel weight, and have no influence on grain yield. The application of Trinexapac-ethyl in stage V9 reduces plant and ear insertion height and 100-kernel weight.

Short communication: Leaf architecture of 35 species of Dipterocarpaceae cultivated in Forest Area with Special Purposes in Carita, Banten, Indonesia

Abstract. MeinataA, Na’iem M, Adriyanti DT, Syahbudin A. 2021. Short communication: Leaf architecture of 35 species of Dipterocarpaceae cultivated in Forest Area with Special Purposes in Carita, Banten, Indonesia. Biodiversitas 22: 2952-2960. Dipterocarpaceae is a major commercial timber characterized by high unbranched bole, paired stipules, and winged fruit. The identification process in the family becomes problematic, in cases where the generative organ is absent. Therefore, a new approach needs to be established to address any misidentification leading to improper utilization. This study aims to determine the leaf architecture in 35 species of Dipterocarpaceae cultivated in Forest Area with Special Purposes (KHDTK) Carita, Banten, Indonesia. The ten leaf samples collected were the third and fourth leaves from terminal shoots of a single tree of each species. Subsequently, the data were observed and measured based on the 17 morphological characters. Each character was then scored and analyzed using multivariate analyses cluster to determine the relationship between species. Dipterocarpaceae generally has pinnate leaf category, geniculate petiole, and entire margin. Furthermore, the phenon line in the dendrogram is cut at 0.695 similarity level to establish meaningful interpretation. The 35 species observed were grouped into 4 major clusters. Small leaf group, inconsistent tertiary vein pattern group, symmetrical leaves with cordate base leaf group, and other groups that do not resemble mentioned characters. The key determination comprised 34 couplets with three characters repeated due to limited descriptors.

Correlating Structure and Morphology of Andiroba Leaf (Carapa guianensis Aubl.) by Microscopy and Fractal Theory Analyses

The Amazon rainforest is considered a megadiverse biome, where several species of its rich flora are still unknown. The anatomy of their leaves usually identifies species. In this paper, we present a complete characterization of the leaf surface of Amazon Carapa guianensis Aubl. (Andiroba), using microscopy and fractal theory to be considered a possible tool for investigating different leaves spatial patterns, especially in species with similar leaf architecture. The SEM results revealed the cellular structures and other non-cellular structures that make up the leaf architecture, both for the abaxial and adaxial sides. The cells responsible for the plant photosynthesis process were observed in the internal structure of the leaf. The wettability analysis showed that the abaxial side is more hydrophobic, while the adaxial side is more hydrophilic. AFM images exposed the relevant details of the microstructure of the leaf abaxial side, such as stomata, pores, furrows, contour, particles, and rough profiles generated by topographic irregularities. The statistical parameters revealed that the scale size influences the topographic roughness, surface asymmetry, and shape of the height distribution, also observed by advanced parameters obtained according to the standard of the international organization for standardization (ISO). The fractal and advanced fractal parameters confirmed changes in spatial patterns as a function of scale size. The largest area exhibited greater spatial complexity, low dominant spatial frequencies, more excellent surface percolation, intermediate topographic homogeneity, and high uniformity of spatial patterns.

Short Communication: Leaf architectural analysis of confusing Syzygium species: Syzygium aqueum (Burm.f.) Alston and Syzygium samarangense (Blume) Merr. & L.M.Perry (Myrtaceae)

Abstract. Viacrucis III JDL, Buot Jr. IE. 2021. Short Communication: Leaf architectural analysis of confusing Syzygium species: Syzygium aqueum (Burm.f.) Alston and Syzygium samarangense (Blume) Merr. & L.M.Perry (Myrtaceae). Biodiversitas 22: 3341-3348. Among species of Myrtaceae family which has economic and ecological importance are the two Syzygium species, Syzygium aqueum and Syzygium samarangense. Both species are cultivated throughout the tropics because of their edible fruits and medicinal properties of various plant parts. However, despite their wide utilization, the two species are often confusing due to their morphological similarity. In this study, leaf architecture of S. aqueum and S. samarangense have been evaluated to delineate the two confusing taxa. Selected laminal and venation characters were compared. Results showed many similar characters shared between the two species, however, laminar size, apex and base shape, areolation, and freely ending veinlets (FEVs) were found to be distinct. Multivariate analyses, cluster analysis employing Gower similarity index, using unweighted pair-group average (UPGMA) and single linkage (nearest neighbor) algorithm, and ordination using Principal Coordinates Analysis (PCoA), illustrated that they are grouped separately. The variations in laminal and venation characters are additional set of information that will allow accurate differentiation of the two species. However, it is recommended that additional taxonomical analysis using various methods, such as molecular techniques, be employed and characters, such as floral morphology, be studied to contribute in the resolution of the taxonomic complexity of this group and other taxonomic controversies

Allometric models for non-destructive leaf area measurement of stevia: an in depth and complete analysis

ABSTRACT Leaf area measurement is pivotal for plant physiologists. Hence, accurate measurement of their leaf area is incredibly relevant in agronomic terms. The plant Stevia rebaudiana is a sucrose-free plant species that is now vital to the global production of sucrose-free foods. Here, we estimated S. rebaudiana leaf area using a nondestructive methodology comprising allometric equations. Through leaf length (L), leaf width (W), and/or their product (LW) the leaf area was determined. One thousand leaves were sampled from four distinct S. rebaudiana genotypes for model construction. Linear or power models were generated, and the best equation was selected using a statistical criterion. The statistical criteria indicated that the linear models best suited all genotypes tested, included a function of LW, exhibited increased stability, and precisely estimated coefficients. ANOVA revealed that both generalized and combined equations were feasible. Nevertheless, grouping all genotypes into a single model was not possible as the genotype leaf architectures were very dissimilar.

Self-assembled leaf architecture of 3D tremella-like (BiOCOOH)x(Bi2MoO6)1-x solid solution nanophotocatalyst with effective photodegradation of medication effluent in sun spectrum: In-situ ultrasound-induced solvothermal design

The novel (BiOCOOH)x(Bi2MoO6)1-x solid solution as nanophotocatalysts (0 ≤ x ≤ 1), with unique 3D, tremella-like architecture containing self-assembled leaf-like nanosheets have been synthesized through in situ ultrasound-induced solvothermal technique to photodegrade medication effluents under simulated sunlight irradiation. Besides, the efficacy of ultrasound microjets was evaluated. To elucidate the promoted photocatalytic function of the (BiOCOOH)0.25(Bi2MoO6)0.75-US as an optimal nanophotocatalyst, Ultraviolet–Visible diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), Brunauer-Emmett-Teller and Barrett-Joyner-Halenda (BET-BJH), field-emission scanning electron microscopy (FESEM), Energy-dispersive X-ray spectroscopy-Dot mapping (EDX), transmission electron microscopy (TEM) and photoluminescence (PL) analyses were conducted. BET-BJH analysis of the mentioned photocatalyst released suitable porosity, pore volume, and surface area, which are important factors. UV–Vis DRS of (BiOCOOH)0.25(Bi2MoO6)0.75-US illuminated the absorption edge at 465.6 nm, indicating the capability of producing electron-hole pairs in a larger area. Furthermore, its morphology analyses demonstrated the tremella-like architecture consisting of nanosheets as self-assembled leaf-like nanosheets. The photodegradation of ofloxacin, tetracycline hydrochloride and levofloxacin over (BiOCOOH)0.25(Bi2MoO6)0.75-US was obtained 94.7, 82.2, and 80.5%, respectively, due to the impact of the solid solution structure and ultrasound microjets leading to the effectual mass transfer and adsorption of contaminant molecules, effective harvesting/penetration of the light, and desirable happening of reduction and oxidation surface reactions.

Characterization and delineation of two infraspecific taxa of Dioscorea esculenta (Lour.) Burkill: The leaf architecture approach

Abstract. Antonio MA, Buot Jr. IE. 2021. Characterization and delineation of two infraspecific taxa of Dioscorea esculenta (Lour.) Burkill: The leaf architecture approach. Biodiversitas 22: 1783-1789. The current taxonomic treatment for the wild and cultivated species of Dioscorea esculenta Lour. (Burkill) presented them as two different varieties. However, there are confusions among botanists and farmers. So, leaf architecture analysis was done to investigate whether leaf architecture data would support their current taxonomic treatment. The varieties showed variability in several characteristics indicating their distinct identity from each other. Based on general leaf characters, they differ in all the parameters observed. But on venation characters, evident variation was seen only on the number of basal veins and secondary vein angle of divergence. Nevertheless, the two varieties resemble each other in a number of characters, i.e. campylodromous primary veins, brochidodromous secondary veins, presence of intermarginal and intersecondary veins, admedially ramified tertiary veins, and well-developed areolation. Dendrogram generated from cluster analysis agrees with and supports above leaf architectural examination, suggesting the two varieties to be recognized as separate taxa. But the current taxonomic treatment naming them as var. spinosa and var. fasciculata seemed to have dragged the cultivated plant into the classification system generally used for wild plants. Thus, the proposed name for the cultivated plant is D. esculenta ‘fasciculata’ while that of the wild plant remains as D. esculenta var. spinosa.

New records of fossil leaves from Abunã Basin, Upper Pleistocene, Rondônia, Brazil

ABSTRACT Detailed descriptions were carried out for four (4) new leaves morphotypes belonging to Calophyllaceae (Calophyllum sp.), Chrysobalanaceae (Couepia sp.) and Fabaceae (Morphotype 1 and Senna sp.), from the Rio Madeira Formation, Upper Pleistocene, Abunã Basin, Rondônia State, Brazil. Detailed characteristics from the leaf architectures show the similarity of the specimens here analysed with their representatives that are established in the current forest cover. The presence of these families in this basin indicates a paleoclimate as well as a paleoenvironment with similar conditions to the present, thus supporting the inference that they could have been important components of paleoflora. These new records are unpublished for the Neopleistocene in the amazon region, increasing the geographic distribution for the families reported here.

Anatomical variation of mesophyll conductance due to salt stress in Populus cathayana females and males growing under different inorganic nitrogen sources.

Synergistic regulation in leaf architecture and photosynthesis is essential for salt tolerance. However, how plant sex and inorganic nitrogen sources alter salt stress-dependent photosynthesis remains unknown. Leaf anatomical characteristics and photosynthesis of Populus cathayana Rehder females and males were investigated under salt stress conditions combined with nitrate NO3- and ammonium NH4+ supplies to clarify the underlying mechanisms. In salt-stressed females, we observed an increased mesophyll spongy cell density, a reduced chloroplast density, a decreased surface area of chloroplasts adjacent to the intercellular air space (Sc/S) and an increased mesophyll cell area per transverse section width (S/W), consequently causing mesophyll conductance (gm) and photosynthesis inhibition, especially under NH4+ supply. Conversely, males with a greater mesophyll palisade tissue thickness and chloroplast density, but a lower spongy cell density had lower S/W and higher Sc/S, and higher gm and photosynthesis. NH4+-fed females had a lower CO2 conductance through cell wall and stromal conductance perpendicular to the cell wall, but a higher chloroplast conductance from the cell wall (gcyt1) than females supplied with NO3-, whereas males had a higher chloroplast conductance and lower CO2 conductance through cell wall when supplied with NO3- instead of NH4+ under salt stress. These findings indicate sex-specific strategies in coping with salt stress related to leaf anatomy and gm under both types of nitrogen supplies, which may contribute to sex-specific CO2 capture and niche segregation.

Mapping quantitative trait loci and predicting candidate genes for leaf angle in maize

Leaf angle of maize is a fundamental determinant of plant architecture and an important trait influencing photosynthetic efficiency and crop yields. To broaden our understanding of the genetic mechanisms of leaf angle formation, we constructed a F3:4 recombinant inbred lines (RIL) population to map QTL for leaf angle. The RIL was derived from a cross between a model inbred line (B73) with expanded leaf architecture and an elite inbred line (Zheng58) with compact leaf architecture. A sum of eight QTL were detected on chromosome 1, 2, 3, 4 and 8. Single QTL explained 4.3 to 14.2% of the leaf angle variance. Additionally, some important QTL were confirmed through a heterogeneous inbred family (HIF) approach. Furthermore, twenty-four candidate genes for leaf angle were predicted through whole-genome re-sequencing and expression analysis in qLA02-01and qLA08-01 regions. These results will be helpful to elucidate the genetic mechanism of leaf angle formation in maize and benefit to clone the favorable allele for leaf angle. Besides, this will be helpful to develop the novel maize varieties with ideal plant architecture through marker-assisted selection.

Designing the RAL Tier-1 Network for HL-LHC and Future data lakes

The Rutherford Appleton Laboratory (RAL) runs the UK Tier-1 which supports all the LHC experiments, as well as a growing number of others in HEP, Astronomy and Space Science. In September 2020, RAL was provided with funds to upgrade its network. The Tier-1 not only wants to meet the demands of LHC Run 3, it also wants to ensure that it can take an active role in data lake development and the network data challenges in the preparation for HL-LHC. It was therefore decided to completely rebuild the Tier-1 network with a Spine / Leaf architecture. This paper describes the network requirements and design decision that went into building the new Tier-1 network. It also includes a cost analysis, to understand if the ever increasing network requirements are deliverable in a continued flat cash environment and what limitations or opportunities this may place on future data lakes.

Leaf morphoanatomy of an endemic massaranduba from Chapada Diamantina, Bahia, Brazil

Abstract: The Sapotaceae family is recognized for its economic importance, presenting food, medicinal and timber potential. Pouteria andarahiensis T.D.Penn., popularly known as "massaranduba", is endemic to Chapada Diamantina, Bahia, Brazil, and is currently classified on the IUCN red list as "endangered". Pouteria andarahiensis is little studied, highlighting this work as the first anatomical study for the species. Light microscopy and scanning electron microscopy techniques were used to perform anatomical studies. The species showed characters shared with the family (laticifers and malpiguiaceous trichomes), as well as diagnostic characters and associated with xeromorphy. The data obtained from the leaf architecture can assist in the identification of the species in a vegetative state, while the leaf surface provided unpublished data to the species, indicating the presence of a cuticle with complex ornamentation. Stand out as xeromorphic anatomical features, high stomatal density, high number of trichomes per area, sclerenchymatic columns in the mesophyll and a subepidermal sclerenchyma layer connecting the vascular bundles in the mesophyll.

Response of Canopy Leaf Area Index and Architecture of Tropical Rainforests in Sri Lanka to Climatic Variation along an Altitudinal Gradient

Ground mulching can affect the availability of nitrogen to a common bean crop depending on the C/N relationship. The objective of this paper was to study the response of the crop grown after corn to nitrogen application rates and time, under no-tillage. The study was conducted at the ‘Embrapa-Arroz e Feijao’ experimental station, located in the municipality of Santo Antonio de Goias, GO, Brazil, in 1999 and 2000. The soil of the experimental site was Oxisol and experiments were conducted during the dry season using center pivot sprinkler irrigation. The experiment was conducted in a randomized complete block design, with four replications. The common bean cultivar used was Apore. All treatments received 120 kg/ha of N during the crop cycle, with split applications or not, in different doses twenty days before sowing, at sowing, and at topdressing. The treatments were: T1 (0-0-120 kg/ha), T2 (0-17,5-102,5 kg/ha), T3 (0-40-80 kg/ha), T4 (0-60-60 kg/ha), T5 (0-80-40 kg/ha), T6 (0-120-0 kg/ha), T7 (40-40-40 kg/ha), T8 (0-17,5-102,5 kg/ha), and T9 (0-60-60 kg/ha). In the last two treatments, the corn mulch was chopped. Common bean under no-tillage needed a higher nitrogen dose at sowing in relation to conventional tillage. In the no-tillage system, the appropriate rate of N at sowing was 60kg/ha. When the N rate was higher than 60kg/ha, grain yield decreased. The same N split application rate produced higher yield when the corn mulch was chopped. KEY-WORDS: Phaseolus vulgaris ; N split application; mulch.