Leaf Morphology Research Articles

Preliminary Exploration of Physiology and Genetic Basis Underlying High Yield in Indica–Japonica Hybrid Rice

The utilization of heterosis is of great significance in improving rice yield. To explore the physiological and genetic basis for high yield in indica–japonica hybrid rice, Zheyou18 (z18) and Yongyou12 (y12) were used as materials and compared with indica hybrid rice, Zheyou12 (z12); japonica hybrid rice, Liangyoupeijiu (LYPJ); and the conventional lines zhe04B (04B) and zhehui818 (h818) under seedling growth vigor, functional leaf morphology, chlorophyll content, yield component, panicle trait, and InDel heterosis analysis. Z18 and y12 showed the largest increase in plant height 6 d and 9 d after germination; the root dry weight of z18 was 31.2% and 42.0% higher than its parents on the 12th d. The length of functional leaves ranked in the middle, while the width was the largest, resulting in z18 and y12 having the largest leaf area. Yield components showed that z18 and y12 had the highest number of primary branches, spikelets, and grains, and grain yield, which was 58.1 g in z18, increased by 29.8% and 8.7%, respectively, in comparison with h818 and LYPJ. The InDel genetic distance was significantly positively correlated with single spike weight, with r reaching 0.771, making it the only consistent and most correlated among the seven traits. Therefore, we speculated that as the InDel genetic distance expands, heterosis mainly manifests in the increase in single spike weight. This study comprehensively explored the physiological mechanism of yield improvement in indica–japonica-hybrid rice and used InDel genetic distances to study the genetic basis of heterosis, which will be helpful for future rice yield improvement.

Does local soil factor drive functional leaf trait variation? A test on Neilingding Island, South China.

Leaf traits were affected by soil factors and displayed varietal differences in forest. However, few examples have been reported on the Island ecosystems. We comprehensively investigated 9 leaf traits (leaf length, leaf width, leaf area, SLA, leaf fresh weight, leaf C content, leaf N content, leaf K content, leaf C:N ratio) of 54 main subtropical woody species and soil parameters (soil pH, total C content, total N content, total K content, available N content, available P content, available K content and soil moisture) in Neilingding Island, Shenzhen, southern China. Intra-and interspecific variation of leaf traits were measured and their correlations with soil parameters were explored. The interspecific variations of leaf C:N ratio, leaf N content and leaf fresh weight were higher than their intraspecific variations. The intraspecific variation of leaf K content was larger than that of interspecific one, accounting for 80.69% of the total variance. Positive correlations were found among intraspecific coefficients of variations in leaf morphological traits. The correlation analysis between the variation of intraspecific traits and the variation of soil parameters showed that changes in soil factors affected leaf morphology and stoichiometry. The interaction between soil moisture and soil available P content was the key factor on intraspecific variations of leaf traits including leaf area, leaf fresh weight, leaf C and leaf K content. We concluded that leaf traits of plants in the island were tightly related to soil parameters. Soil parameters, especially soil moisture and available P content, affected plant leaf morphology and stoichiometry at the local scale.

The catalytic triad of rice NARROW LEAF1 involves H234.

NARROW LEAF1 (NAL1) exerts a multifaceted influence on leaf morphology and crop yield. Recent crystal study proposed that histidine 233 (H233) is part of the catalytic triad. Here we report that unlike suggested previously, H234 instead of H233 is a component of the catalytic triad alongside residues D291 and S385 in NAL1. Remarkably, residue 233 unexpectedly plays a pivotal role in regulating NAL1's proteolytic activity. These findings establish a strong foundation for utilizing NAL1 in breeding programs aimed at improving crop yield.

Age-dependent changes in leaf size in apple are governed by a cytokinin-integrated module.

Plants undergo various age-dependent changes in leaf morphology during the transition from the juvenile to the adult stage. However, the precise molecular mechanisms governing these changes in apple (Malus domestica) remain unknown. Here, we showed that CYTOKININ OXIDASE/DEHYDROGENASE5 (MdCKX5), an age-dependent gene, encodes a functional CKX enzyme and serves as the common downstream target of SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) transcription factor MdSPL14 and WRKY transcription factor MdWRKY24 to control the degradation of cytokinin (CK). As the target of mdm-microRNA156a, MdSPL14 interacts with MdWRKY24 to coordinately repress the transcription of MdCKX5 by forming the age-mediated mdm-miR156a-MdSPL14-MdWRKY24 module, which regulates age-dependent changes in CK during the juvenile-to-adult phase transition. We further demonstrated that MdARR6, a type-A ARABIDOPSIS RESPONSE REGULATOR (ARR), is a negative feedback regulator in the CK signaling pathway. Silencing of MdARR6 in apple resulted in large leaves with smaller epidermal cells and a greater number of epidermal cells. Biochemical analysis showed that the mdm-miR156a-MdSPL14-MdWRKY24 module acts as a transcriptional repressor to directly regulate MdARR6 expression, thus controlling the age-dependent changes in leaf size by reducing CK responses. These findings established a link between the age pathway and CK signaling and revealed the molecular mechanism underlying age-dependent changes during the juvenile-to-adult phase transition; our results also provide targets for the genetic improvement of the vegetative phase transition in apple.

Rewiring of a KNOXI regulatory network mediated by UFO underlies the compound leaf development in Medicago truncatula

Class I KNOTTED-like homeobox (KNOXI) genes are parts of the regulatory network that control the evolutionary diversification of leaf morphology. Their specific spatiotemporal expression patterns in developing leaves correlate with the degrees of leaf complexity between simple-leafed and compound-leafed species. However, KNOXI genes are not involved in compound leaf formation in several legume species. Here, we identify a pathway for dual repression of MtKNOXI function in Medicago truncatula. PINNATE-LIKE PENTAFOLIATA1 (PINNA1) represses the expression of MtKNOXI, while PINNA1 interacts with MtKNOXI and sequesters it to the cytoplasm. Further investigations reveal that UNUSUAL FLORAL ORGANS (MtUFO) is the direct target of MtKNOXI, and mediates the transition from trifoliate to pinnate-like pentafoliate leaves. These data suggest a new layer of regulation for morphological diversity in compound-leafed species, in which the conserved regulators of floral development, MtUFO, and leaf development, MtKNOXI, are involved in variation of pinnate-like compound leaves in M. truncatula.

Clustering Analysis of Natural D-borneol Resource Plants Based on Simple Sequence Repeat (SSR) Markers, Leaf Morphology, and Chemical Composition.

D-borneol is a double-loop monoterpene with a wide use in the pharmaceutical, food, and cosmetics industries. Natural D-borneol can be extracted from branches and leaves of D-borneol resource plants. With the widespread use of natural D-borneol, the identification of D-borneol resource plants and the protection of germplasm resources have become the focus of research. In this study, plant leaf morphology, chemical composition, and simple sequence repeat (SSR) molecular marker analysis were used to analyze and cluster 5 species of D-borneol resource plants and their closely related species. It was found that all three analysis methods could distinguish and cluster these D-borneol resource plants to some degree. The result of SSR analysis using capillary electrophoresis was the best, and it could distinguish Mei Pian tree from Yin Xiang as well as Longnao Zhang from An Zhang. The correlation analysis between SSR similarity matrix and leaf morphology analysis and between SSR similarity matrix and chemical composition similarity matrix revealed that they both had significant correlations (P < 0.0001) and the correlation (r = 0.588) between SSR and leaf morphology was a little higher than that (r = 0.519) between SSR and chemical composition. This indicated that the environment had a greater impact on the chemical composition than on leaf morphology. The research findings will offer efficient techniques to cluster natural D-borneol resource plants and establish a theoretical basis for their future development and utilization.

Chromium stress influences several parameters of leaf dynamics and morphology in Oryza sativa L. genotypes

Chromium (Cr) stress is a prevalent abiotic stress that alters various physiological, growth and metabolic parameters in plants. The toxicity of chromium at concentrations up to 100 µM were studied in two common Indian Oryza sativa genotypes, Lalat upland and Swarnaprabha. More chromium accumulated in roots than in leaves in both genotypes, with Lalat upland taking up more chromium than Swarnaprabha. Higher chromium concentrations reduced various physiological traits including stomatal conductance, transpiration rate, photosynthetic water use efficiency, photosynthetic pigments content in both the genotypes, and this decline was more pronounced in Lalat upland. Increase in vapour pressure deficit, sub stomatal carbon dioxide concentration and malondialdehyde content was detected at 100 µM chromium treated genotypes, however the effects were higher in Lalat upland. Confocal microscopy showed stomatal guard cell deformation, greater stomatal area and closed stomatal aperture in the leaves of 100 µM chromium treated Lalat upland plants. Abscisic acid and Salicylic acid content and expression of NCED1 and NCED2 genes involved in stomata aperture regulation were enhanced in Lalat upland and down regulated in Swarnaprabha under chromium stress. Variation in glandular and non-glandular trichome density and length was found in the leaves of chromium stressed plants in both the genotypes. The results suggest that Lalat upland is more sensitive to chromium toxicity than Swarnaprabha at higher chromium concentrations.

Genome Doubling of Northern Spicebush, Lindera benzoin L.

Lindera benzoin is a dioecious understory shrub native to eastern North America. Northern spicebush is a beautiful shrub with a natural round shrub shape, golden-yellow fall foliage, attractive bright red drupes, and precocious yellow flowers in early spring; however, its market value as an ornamental value has been overlooked. To improve the ornamental values of this under-cultivated nursery crop, breeding for a better compact form, larger leaves, enlarged flower clusters and fruit, and increased stress tolerances could all be beneficial. Polyploidy manipulation is a valuable method to improve such traits for many ornamental plants. This study established the genome doubling method by oryzalin-infused solid agar treatment on young northern spicebush seedlings. The seedlings of two wild populations in North Carolina were collected and used. A total of 288 seedlings were treated with solid agar containing 150 µM oryzalin for 24, 72, and 120 h. The results were sporadic in their survival ratios and tetraploid conversion ratios between different treatments; however, a total of 16 tetraploid L. benzoin plants were produced in this study. The 24-h treatment showed the optimal result, with 7.1% of total treated seedlings or 15.2% of surviving seedlings converted into tetraploids. Tetraploid plants had visible differences in leaf morphology, a statistically significant enlarged stomata size, and reduced stomatal density compared to diploid plants. This research provides ploidy manipulation information for all future breeding processes of L. benzoin and related species.

Advancements in Rice Leaf Development Research

Rice leaf morphology is a pivotal component of the ideal plant architecture, significantly impacting rice yield. The process of leaf development unfolds through three distinct stages: the initiation of leaf primordia, the establishment and maintenance of polarity, and leaf expansion. Genes regulating leaf morphology encompass transcription factors, hormones, and miRNAs. An in-depth synthesis and categorization of genes associated with leaf development, particularly those successfully cloned, hold paramount importance in unraveling the complexity of rice leaf development. Furthermore, it provides valuable insights into the potential for molecular-level manipulation of rice leaf types. This comprehensive review consolidates the stages of rice leaf development, the genes involved, molecular regulatory pathways, and the influence of plant hormones. Its objective is to establish a foundational understanding of the creation of ideal rice leaf forms and their practical application in molecular breeding.

Correlation analysis between artemisinin and its derivative contents and trichome characteristics from different Artemisia species

Artemisia species have significant commercial, medical, and economic value and are widely used in the traditional medicine and pharmaceutical industries. Artemisinin, a powerful antimalarial agent, is an important pharmaceutical metabolite that primarily accumulates within the glandular trichomes (GTs) on the leaf surface of Artemisia plants. Trichomes arising from the elongation of epidermal cells can be classified into GTs and non-glandular trichomes (NGTs) based on their morphology. GTs and NGTs are present in Artemisia species, and the relationship between GTs and artemisinin has been extensively studied; however, the correlation between NGTs and artemisinin remains relatively unexplored. In this study, we inferred artemisinin derivatives and trichome characteristics based on the type of species, developmental stage, and leaf age and conducted correlation analyses to investigate the factors influencing artemisinin content across different Artemisia species. Artemisinin and its derivatives exhibited variations in distribution based on species and leaf age, with a decreasing trend observed across most species as the developmental stage progressed. Noticeable differences among Artemisia species were observed in leaf shape, morphology, and trichome distribution. Although the observed data did not evidently differentiate between species, developmental stage, and leaf age groups, principal component analysis revealed that artemisinin was positively associated with the NGTs density, indicating a correlation coefficient of 0.56 (p < 0.0001). Therefore, the number of NGTs may affect the artemisinin content in different Artemisia species.

A new combination and synonym in Bupleurum (Apiaceae, Apioideae), based on morphological, molecular and cytological evidence.

Specimen examinations and field observations revealed that Bupleurumsmithiivar.parvifolium was distinctly different from B.smithiivar.smithii in umbel, leaf, and fruit morphology, but was very similar to B.commelynoideumvar.flaviflorum. Based on these morphological evidences, the present study re-examined the taxonomic status of these taxa through morphological, cytological, and phylogenetic analyses. The results showed distinguishable features in the width of middle leaves and bracteoles of B.smithiivar.parvifolium compared to B.smithiivar.smithii. Morphological variation between B.smithiivar.parvifolium and B.commelynoideumvar.flaviflorum was continuous and overlapping. Notably, the chromosome number of B.smithiivar.parvifolium was 2n = 14 (x = 7), consistent with B.commelynoideumvar.flaviflorum, whereas B.smithiivar.smithii was 2n = 64 (x = 8). Additionally, phylogenetic analyses revealed B.commelynoideumvar.flaviflorum nested within B.smithiivar.parvifolium, and that both were distant from the B.smithiivar.smithii and B.commelynoideumvar.commelynoideum. Based on the evidence above, the differences between B.smithiivar.parvifolium and B.smithiivar.smithii extend beyond the level of intraspecific variation, and B.commelynoideumvar.flaviflorum is considered to be identical with B.smithiivar.parvifolium. Hence. A new combination and status, B.parvifolium (Shan & Y.Li) Q.R.Liu & L.H.Wang, comb. et stat. nov., is proposed. Furthermore, B.commelynoideumvar.flaviflorum should be treated as a synonym of B.parvifolium.

DNAL7, a new allele of NAL11, has major pleiotropic effects on rice architecture.

dnal7, a novel allelic variant of the OsHSP40, affects rice plant architecture and grain yield by coordinating auxins, cytokinins, and gibberellic acids. Plant height and leaf morphology are the most important traits of the ideal plant architecture (IPA), and discovering related genes is critical for breeding high-yield rice. Here, a dwarf and narrow leaf 7 (dnal7) mutant was identified from a γ-ray treated mutant population, which exhibits pleiotropic effects, including dwarfing, narrow leaves, small seeds, and low grain yield per plant compared to the wild type (WT). Histological analysis showed that the number of veins and the distance between adjacent small veins (SVs) were significantly reduced compared to the WT, indicating that DNAL7 controls leaf size by regulating the formation of veins. Map-based cloning and transgenic complementation revealed that DNAL7 is allelic to NAL11, which encodes OsHSP40, and the deletion of 2 codons in dnal7 destroyed the His-Pro-Asp (HPD) motif of OsHSP40. In addition, expression of DNAL7 in both WT and dnal7 gradually increased with the increase of temperature in the range of 27-31°C. Heat stress significantly affected the seedling height and leaf width of the dnal7 mutant. A comparative transcriptome analysis of WT and dnal7 revealed that DNAL7 influenced multiple metabolic pathways, including plant hormone signal transduction, carbon metabolism, and biosynthesis of amino acids. Furthermore, the contents of the cytokinins in leaf blades were much higher in dnal7 than in the WT, whereas the contents of auxins were lower in dnal7. The contents of bioactive gibberellic acids (GAs) including GA1, GA3, and GA4 in shoots were decreased in dnal7. Thus, DNAL7 regulates rice plant architecture by coordinating the balance of auxins, cytokinins, and GAs. These results indicate that OsHSP40 is a pleiotropic gene, which plays an important role in improving rice yield and plant architecture.

Examining preharvest genetic and morphological factors contributing to lettuce (Lactuca sativa L.) shelf-life

Lettuce is a highly perishable horticultural crop with a relatively short shelf-life that limits its commercial value and contributes to food waste. Postharvest senescence varies with influences of both environmental and genetic factors. From a larger pool of romaine lettuce genotypes, we identified three genotypes with variable shelf lives and evaluated their leaf morphology characteristics and transcriptomic profiles at preharvest to predict postharvest quality. Breeding line 60184 had the shortest shelf-life (SSL), cultivar ‘Manatee’ had an intermediate shelf-life (ISL), and ‘Okeechobee’ had the longest shelf-life (LSL). We observed significantly larger leaf lamina thickness and higher stomatal index in the SSL genotypes relative to the LSL cultivar. To identify molecular indicators of shelf-life, we used a transcriptional approach between two of the contrasting genotypes, breeding line 60184 and cultivar ‘Okeechobee’ at preharvest. We identified 552 upregulated and 315 downregulated differentially expressed genes between the genotypes, from which 27% of them had an Arabidopsis thaliana ortholog previously characterized as senescence associated genes (SAGs). Notably, we identified several SAGs including several related to jasmonate ZIM-domain jasmonic acid signaling, chlorophyll a–b binding, and cell wall modification including pectate lyases and expansins. This study presented an innovative approach for identifying preharvest molecular factors linked to postharvest traits for prolonged shelf.

Oak leaf morphology may be more strongly shaped by climate than by phylogeny

Key messageDespite been grown under the same climate, oak species are able to correlate with looser, but still identifiable, leaf morphological syndromes, composed by morphological traits with an ecological role in their respective macroclimates.ContextEnvironmental restrictions imposed by climate have been shown to modulate leaf morphology. A reduction of leaf area in hot and dry climates reduces overheating because of a thinner boundary layer. Lobed shapes enhance hydraulic conductivity and faster cooling. Elongated leaves drain more quickly under high precipitation. Trichomes may help to reduce the effects of excessive sun exposure in hot and dry environments. Leaf mass per area (LMA) increases in stressful environments.AimTo assess the influence of global climate and clade on oak leaf syndromes comprising morphological traits with ecological roles.MethodsWe analyzed seven morphological traits in 141 oak species grown in a botanical garden, characterized into five macroclimates, and explored the partial effects of clade and climate.ResultsWe found significant associations between macroclimate and every morphological trait measured. Temperate species tend to have large, obovate, lobed, malacophyllous leaves. Species occurring in dry habitats usually present small, rounded, pubescent, sclerophyllous leaves. Warm and wet climates induce the development of slender, lanceolate, glabrous leaves with an acuminate apex.ConclusionThe functional roles of the different morphological traits are partially confirmed in genus Quercus as a response to the different macroclimates, where different leaf syndromes can be distinguished.

The changes of chili leaf structure by Geminivirus infection

The Geminivirus in chili plants is a significant problem in chili cultivation. Symptoms of Geminivirus infection are quite easy to find in chili plants because the symptoms are quite typical: mosaic, yellowing, small leaves, leaf lamina malformation, and stunting. The visual changes in leaf morphology are due to the leaf tissue structure, such as the upper and lower epidermis and the mesophyll tissue, including the palisade and sponge. There is little information about changes in the structure of chili plants infected with the Geminivirus. Therefore, this study aims to add information about changes in the leaf tissue structure of chili plants infected with the Geminivirus. The structural changes observed were palisades. Long palisades were less preferred by whiteflies, so the incidence of geminivirus disease was lower. This information is a reference for assembling chili plants with better structural resistance. The method used was a cross-section of chili leaves, double staining, and observation with a light microscope. Observations on mild symptoms showed epidermal cells shrinking. Some parts of palisade leaves were composed of two layers with shortened cells and tend to be oval. The symptom is that the upper epidermal cells were shrunken, and the palisade also tends to shorten. Severe symptoms of the epidermis on the leaves were curly, shriveled, thinned, and even dying; the palisade is shortened and sometimes looks irregular/tight. Changes in the leaf tissue of chili plants infected with the Geminivirus cause changes at the ultra-structural, cell, or tissue level, depending on the type of virus attack and the attack level.

Unveiling the silver lining: examining the effects of biogenic silver nanoparticles on the growth dynamics of in vitro olive shoots

The current study aimed to evaluate the effects of biogenic silver nanoparticles (AgNPs) on growth behavior and leaf anatomy of in vitro growing shoots of ‘Picual’ and ‘Dolce’ olive cultivars. Biosynthesis of AgNPs was carried out using the cell-free filtrate of Fusarium oxysporum. The dimension and shape of the synthesized AgNPs have been analyzed using spectroscopy and topography analysis tools, confirming that the biosynthesis of AgNPs is a crystalline nanostructure with an average particle size of 37 nm. The shoots of the selected olive cultivars were cultured on Rugini olive medium-supplemented AgNPs at 0, 10, 20, and 30mg L− 1. The effect of genotypes on shoot multiplication was significant, ‘Picual’ recorded higher values of shoot growth parameters compared with ‘Dolce’ cultivar. Adding AgNPs to the culture medium significantly affected the growth of in vitro olive shoots. AgNPs at 20 and 30mg L− 1 produced higher values of the number of shoots, shoot length, and leaf number of Picual cv. compared with the control treatments, but the higher AgNPs concentration harmed the growth parameters of Dolce cv. and recorded lower growth values compared with the lower concentration (10mg L− 1). AgNPs had a significant effect on leaf morphology and their anatomical structure. The current results showed that the stimulatory effect of AgNPs on shoot growth of in vitro olive shoots is highly dependent on plant genotype and nanoparticle concentration.

Towards a comprehensive understanding of zinc tolerance in Limonium brasiliense as a useful tool for environmental remediation and monitoring.

Heavy metal pollution is a serious environmental problem worldwide, creating the necessity to find eco-friendly strategies for monitoring and remediating environments. This study aimed to evaluate morphological, physiological, and biochemical responses as indicative of Zn tolerance in Limonium brasiliense and to determine the ability of this halophyte to accumulate different concentrations of Zn (0, 100, and 200 μM) in hydroponic conditions. The leaf shape at high Zn concentration showed enlarged petioles and lanceolate blades, whereas the leaf size was reduced. Water content, chlorophyll fluorescence parameters, and pigment content decreased with Zn addition. Of the antioxidant activities, only APx increased 75% compared to the control by Zn stress. Zn concentration was higher in aerial structures than in roots (BAC>1 and TF>1), suggesting that L. brasiliense could function as an accumulator of Zn. Its great ability to resist metal stress and its strong capacity to protect itself against high Zn concentration postulate it as a good phytoremediation of environments enriched with Zn. The study emphasizes using leaf morphology as an early biomonitoring tool for detecting Zn pollution, providing more evidence of their potential use as a biomarker for evaluating and assessing ecosystem health in biomonitoring programs.

Comprehensive Evolutionary Analysis of the SMXL Gene Family in Rosaceae: Further Insights into Its Origin, Expansion, Diversification, and Role in Regulating Pear Branching.

SMXL genes constitute a conserved gene family that is ubiquitous in angiosperms and involved in regulating various plant processes, including branching, leaf elongation, and anthocyanin biosynthesis, but little is known about their molecular functions in pear branching. Here, we performed genome-wide identification and investigation of the SMXL genes in 16 angiosperms and analyzed their phylogenetics, structural features, conserved motifs, and expression patterns. In total, 121 SMXLs genes were identified and were classified into four groups. The number of non-redundant SMXL genes in each species varied from 3 (Amborella trichopoda Baill.) to 18 (Glycine max Merr.) and revealed clear gene expansion events over evolutionary history. All the SMXL genes showed conserved structures, containing no more than two introns. Three-dimensional protein structure prediction revealed distinct structures between but similar structures within groups. A quantitative real-time PCR analysis revealed different expressions of 10 SMXL genes from pear branching induced by fruit-thinning treatment. Overall, our study provides a comprehensive investigation of SMXL genes in the Rosaceae family, especially pear. The results offer a reference for understanding the evolutionary history of SMXL genes and provide excellent candidates for studying fruit tree branching regulation, and in facilitating pear pruning and planting strategies.

A taxonomic resolution of Hibbertia acerosa (Dilleniaceae) in Western Australia

Close study of the widely-distributed southwestern Western Australian Hibbertia acerosa (R.Br. ex DC.) Benth. (Dilleniaceae) has revealed that it comprises four distinct, parapatric or narrowly sympatric species differing in leaf morphology, sepal indumentum and floral bract shape. One of the segregate species has an earlier name in Pleurandra, which is recombined here as Hibbertia juniperina (Turcz.) K.R.Thiele. The new species H. simkiniae K.R.Thiele and H. callida K.R.Thiele are described, the former for a relatively restricted species occurring inland of Kalbarri and the latter for the most widespread segregate from H. acerosa sens. lat. The true H. acerosa sens. str. is redescribed to account for its narrower circumscription, and a key and distribution maps provided for all taxa.

Identification and Transcriptome Analysis of a Novel Allelic Mutant of NAL1 in Rice.

Leaf morphology is a crucial aspect of plant architecture, yet the molecular mechanisms underlying leaf development remain incompletely understood. In this study, a narrow leaf mutant, m625, was identified in rice (Oryza sativa L.), exhibiting pleiotropic developmental defects. Pigment measurement revealed reduced levels of photochromic pigments in m625. Cytological analysis demonstrated that the m625 gene affected vascular patterns and cell division. Specifically, the narrowing of the leaf was attributed to a decrease in small vein number, shorter vein spacing, and an abnormal V-shaped arrangement of bulliform cells, while the thickening was caused by longer leaf veins, thicker mesophyll cells, and an increased number of parenchyma cell layers. The dwarf stature and thickened internode were primarily due to shortened internodes and an increase in cell layers, respectively. Positional cloning and complementation assays indicated that the m625 gene is a novel allele of NAL1. In the m625 mutant, a nucleotide deletion at position 1103 in the coding sequence of NAL1 led to premature termination of protein translation. Further RNA-Seq and qRT-PCR analyses revealed that the m625 gene significantly impacted regulatory pathways related to IAA and ABA signal transduction, photosynthesis, and lignin biosynthesis. Moreover, the m625 mutant displayed thinner sclerenchyma and cell walls in both the leaf and stem, particularly showing reduced lignified cell walls in the midrib of the leaf. In conclusion, our study suggests that NAL1, in addition to its known roles in IAA transport and leaf photosynthesis, may also participate in ABA signal transduction, as well as regulate secondary cell wall formation and sclerenchyma thickness through lignification.