Cotyledon Shape Research Articles

Morphological diversity and taxonomic implications of seedling structures in selected species of Fabaceae from Karachi (Pakistan)

Seedling morphology is a valuable tool for plant identification and classification, particularly in early growth stages. This study investigates the morphological characters of seedlings from randomly selected taxa within the Fabaceae family, focusing on cotyledons, first two leaves, and subsequent leaves to support taxonomic differentiation. Not all subfamilies within Fabaceae are fully represented in this study. Seedlings from 14 randomly selected taxa were analyzed using morphological traits such as cotyledon shape, phyllotaxy, leaf shape, and venation patterns. An artificial key was constructed, and three dendrograms were developed based on cotyledon morphology, first two leaves, and subsequent leaves to illustrate taxonomic relationships. Statistical analyses were employed to assess clustering patterns among the taxa. The artificial key categorized the taxa into subfamilies within Fabaceae, including Caesalpinoideae, Mimosoideae, and Papilionoideae, based on cotyledon shape and leaf morphology. Dendrogram analysis revealed distinct clustering patterns, grouping species according to key morphological features. Not all subfamilies of Fabaceae were covered, but the analysis provided clear separation among the species studied. The morphological traits observed were consistent with previous taxonomic findings and offered a reliable basis for classification. The morphological features of seedlings, especially cotyledons and eophylls, serve as reliable taxonomic markers for identifying and classifying species within Fabaceae. Although the study does not encompass all subfamilies, the randomly selected taxa demonstrated clear taxonomic distinctions. Dendrograms combined with artificial keys provided a useful framework for classification. Further studies should expand the scope to include more taxa, covering all subfamilies of Fabaceae. Integrating molecular and other taxonomic tools such as anatomy, cytology, and chemistry can enhance the precision of classification frameworks and provide deeper insights into the evolutionary relationships within the family.

Morphological characterization of some local watermelon (Citrullus lanatus L.) genotypes of Turkey

The scope of this study, some of the local Turkish watermelon genotypes were evaluated morphologically. A total of 20 local genotypes and three commercial varieties were assessed regarding their cotyledon, leaf, fruit, and seed phenotypes. An extensive morphological analysis was performed on a diverse set of genotypes. Traits such as cotyledon shape and color intensity, leaf size and lobing, and fruit size, shape, and color were measured and compared. Hierarchical clustering analysis, correlation matrices, and principal component analysis were employed to interpret the data. The study revealed significant morphological variability among the watermelon genotypes. Cotyledons ranged from narrow to broad, with a predominance of large sizes and dark green coloration. Leaf characteristics varied widely, with a notable distribution across different sizes and degrees of lobing. Fruit analysis showed a broad spectrum of shapes, sizes, and colors, indicating a rich genetic diversity. Two main genotype clusters were identified, suggesting a clear distinction based on morphological traits.

Smooth Elongation ofPavement Cells Induced by RIC1 Overexpression Leads to Marginal Protrusions ofthe Cotyledon inArabidopsis thaliana.

The interdigitated pavement cell shape is suggested to be mechanically rational at both the cellular and tissue levels, but the biological significance of the cell shape is not fully understood. In this study, we explored the potential importance of the jigsaw puzzle-like cell shape for cotyledon morphogenesis in Arabidopsis. We used a transgenic line overexpressing a Rho-like GTPase-interacting protein, ROP-INTERACTIVE CRIB MOTIF-CONTAINING PROTEIN 1 (RIC1), which causes simple elongation of pavement cells. Computer-assisted microscopic analyses, including virtual reality observation, revealed that RIC1 overexpression resulted in abnormal cotyledon shapes with marginal protrusions, suggesting that the abnormal organ shape might be explained by changes in the pavement cell shape. Microscopic, biochemical and mechanical observations indicated that the pavement cell deformation might be due to reduction in the cell wall cellulose content with alteration of cortical microtubule organization. To examine our hypothesis that simple elongation of pavement cells leads to an abnormal shape with marginal protrusion of the cotyledon, we developed a mathematical model that examines the impact of planar cell growth geometry on the morphogenesis of the organ that is an assemblage of the cells. Computer simulations supported experimental observations that elongated pavement cells resulted in an irregular cotyledon shape, suggesting that marginal protrusions were due to local growth variation possibly caused by stochastic bias in the direction of cell elongation cannot be explained only by polarity-based cell elongation, but that an organ-level regulatory mechanism is required.

Efficient somatic embryogenesis and regeneration from leaf main vein and petiole of Actinidia chinensis planch. via thin cell layer culture technology

Somatic embryogenesis (SEMs) is an effective micropropagation method that has been successfully applied to many different plant species; however, little is known about the SE in Actinidia chinensis Planch. - A species with high economic value. In this study, the efficiency of SEMs from leaf main vein and petiole of A. chinensis (seedlings germinated from seeds sterilized with 200 ppm silver nanoparticles for 7 min) via thin cell layer (TCL) technique was performed and compared with that of whole leaf main vein and whole petiole explants. The leaf main vein (mv - 1 mm × 10 mm in size) and leaf petiole (p - 1 mm × 10 mm in size) explants of in vitro A. chinensis were cut through transverse and longitudinal TCL (mv-tTCL and mv-lTCL for mv explants or p-tTCL and p-lTCL for p explants) with different sizes (½, ¼, 1/6, 1/8 of mv-lTCL or p-lTCL and ½, 1/3, ¼ of mv-tTCL or p-tTCL, respectively). Somatic embryo (SE) was recorded in the wounds of mv and p explants after 8 weeks of culture. For mv explants which cultured on MS medium supplemented with 0.02 mg/L NAA, 0.5 mg/L TDZ, 30 g/L sucrose and 8 g/L agar – MSE medium, the ½ mv-tTCL explant (mv was cut into 2 tTCL explants) gave the highest SEMs (98.67%) and number of somatic embryos per explant (10.66 embryos); meanwhile, p explants cultured on MSE medium, the ½ p-tTCL explant (p was cut into 2 tTCL explants) obtained the highest number of somatic embryos per explant (8.66 embryos) after 8 weeks of culture. In addition, the growth correction factor of SEMs was optimal at ½ mv-tTCL explant (21.04) or 1/6 p-lTCL (p was cut into 6 lTCL explants) and 1/8 p-lTCL (p was cut into 8 lTCL explants) (31.36 and 32.00). The current study has shown that the procedure of leaf main vein and petiole TCL derived- SEMs of A. chinensis is the optimal one. Large amounts of somatic embryo induction were observed from mv-TCL and p-TCL with full shapes of the globular, heart, torpedo and cotyledon. The shoot regeneration from somatic embryo with the cotyledon shape was optimal on medium containing 1.0 mg/L BA in terms of total number of shoots, shoot height and number of shoots. In addition, plantlets derived from shoot cultured on the MS medium supplemented with 0.4 mg/L NAA and planted in plastic pots with the combination of humus, coconut fiber and biofertilizers substrates (with ratio of 2:3:1 in weight) showed higher acclimatization and growth than those from other treatments in the greenhouse.

Seed Characterization and Relationships between Seed and Cotyledon Properties in Lagenaria spp. Accessions

Bottle gourd [Lagenaria siceraria (Molina) Standl.] is widely produced in some Asian and African countries as a fresh vegetable as well as for seed consumption. A major use of bottle gourd is for rootstocks in grafted watermelon production. There are several centers where bottle gourd genetic resources are maintained, with the U.S. Department of Agriculture (USDA) germplasm collection being one of the most important. There is little published information on the relationship between seed morphology and the early establishment of seedlings in bottle gourd. The objective of this study was to determine seed characterization, morphology, and cotyledon shape in 163 Lagenaria spp. accessions and measure any relationship between seed and cotyledon characteristics. In USDA Lagenaria germplasm, it has been determined that the common character in seeds was medium in terms of seed size (53% of accessions), intermediate in seed surface lustre (39% of accessions), brown in seedcoat color (89% of accessions), thin and uniform in seed margin (35% of accessions), and tan in seed margin color (64% of accessions). According to the research results, seed weight ranged from 0.11 g (PI 500820) to 0.36 g (PI 675112), seed length from 13.17 mm (PI 500820) to 23.68 mm (PI 675112), and seed width from 5.86 (PI 500808) to 11.21 mm (PI 491274). Cotyledon length ranged from 5.46 cm (PI 368640) to 2.47 cm (PI 381850). The widest cotyledon was 3.00 cm (PI 534552), and the narrowest was 1.50 cm (PI 381831). Interesting correlations were observed for seed weight with seed length (R2 = 0.259), and cotyledon length with cotyledon width (R2 = 0.547).

Seedling Morphology and Molecular Characterisation of some Ocimum L. species (Lamiaceae) in Southwest states of Nigeria.

The genus Ocimum L. (Lamiaceae) is composed of aromatic plants known for their peculiar strong smell added to their close similarities in morphological attributes, increase attention and applications as ethnobotanicals of culinary and medicinal use. There are reports of difficulty in Ocimum taxonomy. Seedling morphology and molecular characterization of some Ocimum accessions collected from Southwest states of Nigeria were carried out to delimit members of the genus. Morphological measurements were carried out on the seedlings characters and recorded. Molecular characterization was carried out on their fresh leaf‐samples. Statistical analyses of quantitative seedling data were performed using SAS/PC1 version 9.01. Seedling morphology reveals phanerocotylar epigeal with foliaceous cotyledon type; reniform and flabellate cotyledon shape, obcordate and obtuse cotyledon apex, cordate and truncate cotyledon base. There is a significant mean difference in all the quantitative seedling characters at p<0.05. Blast query reveals the accessions as five species exhibiting 99 % homologous identities with previous submissions in the GenBank database.

Embryo and seedling morphology of some Trifolium L. species (Fabaceae).

The present study aims to describe and characterize the The present study aims to describe and characterize the morphology of the embryo and the seedling; including the cotyledonary, the first unifoliate and first trifoliate foliage leaves and their importance in the taxonomy of the studied Trifolium species. Macromorphological (cotyledon, seedling with first unifoliate leaves and first trifoliate leaves) studies carried on 15 Trifolium species. Qualitative and quantitative characteristics of the embryo, seedling with cotyledonary, seedling with first unifoliate and second trifoliate leaves indicated that cotyledon characters (cotyledon shape; L/W ratio, apex, colour, radicle position; shape, apex), cotyledonary leaves (hypocotyl colour, blade shape, L/W ratio), first and second leaves (shape, apex base, margin and texture). Numerical analysis is carried and also phenogram illustrating the relationship between the studied taxa were constructed by calculating the average taxonomic distance. Results have a taxonomic significance in identification and differentiation between the studied 15 Trifolium species. An identification key was prepared.

POLYGALACTURONASE INVOLVED IN EXPANSION3 Functions in Seedling Development, Rosette Growth, and Stomatal Dynamics in Arabidopsis thaliana.

Plant cell separation and expansion require pectin degradation by endogenous pectinases such as polygalacturonases, few of which have been functionally characterized. Stomata are a unique system to study both processes because stomatal maturation involves limited separation between sister guard cells and stomatal responses require reversible guard cell elongation and contraction. However, the molecular mechanisms for how stomatal pores form and how guard cell walls facilitate dynamic stomatal responses remain poorly understood. We characterized POLYGALACTURONASE INVOLVED IN EXPANSION3 (PGX3), which is expressed in expanding tissues and guard cells. PGX3-GFP localizes to the cell wall and is enriched at sites of stomatal pore initiation in cotyledons. In seedlings, ablating or overexpressing PGX3 affects both cotyledon shape and the spacing and pore dimensions of developing stomata. In adult plants, PGX3 affects rosette size. Although stomata in true leaves display normal density and morphology when PGX3 expression is altered, loss of PGX3 prevents smooth stomatal closure, and overexpression of PGX3 accelerates stomatal opening. These phenotypes correspond with changes in pectin molecular mass and abundance that can affect wall mechanics. Together, these results demonstrate that PGX3-mediated pectin degradation affects stomatal development in cotyledons, promotes rosette expansion, and modulates guard cell mechanics in adult plants.

Early Selection of Double Flowers Based on Cotyledon Shape in Cut Stock (Matthiola incana L.) Flowers

Selection of double-flowered plants at the seedling stage is one of the main purposes of stock breeding programs. Eight stock cultivars of Matthiola incana L. named ‘Nobel’, ‘Cinderella’, ‘Pacific’, ‘Avalanche’, ‘Midblue’, ‘Lavender’, ‘Goddess’ and ‘Esfahan’, with different percentage of double-flowered plants were used for examining the relationship with three morphological types of cotyledons. The results of a chi-square test indicated that in heartshaped (HC) and cup-shaped cotyledon (CC) populations, the number of plants with double flowers was much more than that of single flowers and CC seedlings rarely produced single flowers. Therefore, increasing the number of CC seedlings can improve the percentage of double flowers. The highest and lowest numbers of CC seedling were observed in high double and single flower cultivars, respectively. Single flower cultivars showed the maximum count of dumbbell-shaped cotyledons. Chromosome pairing of these cultivars was evaluated using the squash technique. Aneuploid cells were found in ‘Nobel’ and ‘Goddess’ cultivars, which showed the highest percentage of CC seedling. Based on morphological measurements, the highest value of inflorescence size was observed in the seedlings with cup-shaped cotyledons.

Morphological and morphometric evaluation of placenta in hypothyroid mothers

Introduction: Pregnancy has a significant impact on thyroid gland and its function. Hypothyroidism, usually evident as subclinical hypothyroidism, occurs in approximately 2.5% of otherwise normal pregnancies, and is associated with various morphological, histological, and histochemical changes in the placenta. It is, therefore, obvious that hypothyroidism is associated with gross placental abnormalities that compromise placental function and hence fetal growth. Material and Methods: This prospective, observational study was conducted over a period of 1 year from August 2013 to July 2014 in a tertiary care teaching hospital in the state capital of Uttar Pradesh of India. Two groups were formed. Group A (euthyroid) included placenta of uncomplicated pregnancy with full-term delivery to serve as controls for comparison. Group B (hypothyroid) included placenta of patients with hypothyroidism (thyroid stimulating hormone level: ≥3.0 IU/L) diagnosed either before or during pregnancy. Each placenta was observed for shape, diameter, and number of cotyledons. Two groups were compared for these variables. Statistical analysis was performed using Statistical Package for Social Sciences version 15.0 statistical analysis software. The values were represented in number (%) and mean ± standard deviation. P value was calculated for each variable, and P value less than 0.05 was considered to be statistically significant. Results: A total of 70 subjects were included. Group A comprised of 20 and Group B of 50 subjects. Circular shape of placenta was more common in group B and the difference was statistically significant (P = 0.037). Mean diameter, cotyledon size, and mean thickness were higher in group B as compared to group A. Statistically, significant differences between the two groups were observed for mean diameter (<0.001), cotyledon size (<0.001), and thickness (<0.05) Conclusion: Placenta of hypothyroid mothers was usually circular in shape. It was found to be less heavy and thinner but larger in diameter with more cotyledons in comparison to normal.

Characterization of Citrus Rootstocks Under Sriganganagar Conditions of Zone 1B

Investigation was carried out to evaluate and characterize the available citrus rootstocks and to find out the genetic variability and correlation in between the qualitative/quantitative traits. Fully grown, eleven Citrus types i.e. C. maderaspatana, C. jambhiri var. Mitthi, C. Pectinifera, C. Reshni T, Citrumelo (P. trifoliata x C. sinensis), Carrizo Citrange (P. trifoliate x C. paradisi), C. limonia, C. Karna, C. aurantium, C. Jambhiri var. Jatti-katti and C. limon var. Bhadri Lemon were selected for the study. These exhibited variation for different physico-chemical fruit and seed attributes. Variation in seed characters were also recorded for seed shape, number and colour of cotyledons. Variation were noted for quantitative traits like fruit length (24–210 mm) fruit weight (19–1883 g), TSS (7–10); seed length (7–16 mm), hundred seed weight (16–31 g) and seed number per fruit (2–55). In character association analysis, positive and significant correlation were recorded for fruit weight with fruit size, seed weight with seed size and seed weight with seed germination. Thus, the study revealed that significant amount of genetic variability exists among the available rootstocks. Genetic variability and inter relationship of characters may lead to effective selection of rootstock for commercial multiplication and further improvement programme of citrus plants.

Phenotypic Variations in Camptotheca Decaisne

Variations in shape, size, color, and texture of fruits, shape and size of cotyledons, shape, venation pattern, sur- face and margin characters of mature leaves of 40 populations (either living plants or herbarium specimens) representing all known taxa of Camptotheca have been analyzed within and between populations. A majority of the observed pheno- typic variations for most morphometric measures was among populations. This is probably due largely to selfing and re- lated matings common to both natural and cultivated populations, resulting in the current population structure that now displays a highly fragmented distribution pattern. Trees of different generations from the same seed source but growing in different locations demonstrated minimal variations in both means and frequency distributions of leaf vein number, fruit length, fruit colors, and cotyledon vein number. The trees of different taxa even growing in the same location have sig- nificant difference in main characters particularly fruit color and texture. The key diagnostic characters for the identifica- tion of taxa of Camptotheca are leaf shape, venation type, vein number, stoma size and frequency, outer stomatal rim, subsidiary cell number, and gland size; cotyledon shape, venation type, and vein number; and the fruit surface texture, disc, length, and color.

Micromorphological Variations of Camptotheca Decaisne

The micromorphology of the leaves, pollen, and fruits of different taxa of Camptotheca was studied under light microscope and scanning electron microscope. The key diagnostic characters can be used for the identification of taxa within Camptotheca include leaf shape, venation type, vein number, stoma size and frequency, shape of outer stomatal rim, subsidiary cell number, and glandular trichome size; cotyledon shape, venation type, and vein number; and fruit sur- face texture, disc, length, and color. Other characters could not dependably be used for species level discrimination.

English

The present study assessed whether seed germination of Peganum harmala L. is related to population size and whether factors that control three and four cotyledons and difference in cotyledon shape are different and whether abnormality of cotyledons is related to genetic drift. The percentage of final seed germination was highest in Dzungarian Gobian population and followed by Trans-Altai Gobian population and lowest was in East Gobian population (Tukey HSD test, p&lt;0.01). Most seedlings of P. harmala have two cotyledons in our study areas but there were abnormal cotyledons which are three, four and different shape dicotyledons. Three and four cotyledons showed low frequency in biggest (limited by river basins) and bigger (limited by oasis) populations and high frequency in small population (limited by well) whereas pattern of different shape dicotyledon frequency does not follow difference of population size. The different shape dicotyledons showed higher frequency in region with lower elevation, as compared to regions with higher elevation. The present results suggest that percentage of seed germination of P. harmala and frequency of more than two cotyledons might depend on population size, while frequency of different shape dicotyledons might be related to habitat difference which is high soil salinity. Also, our results suppose more than two cotyledons might be related to genetic drift. &nbsp; Key words: Abnormality of cotyledons, genetic drift, population size, seed germination.

&lt;b&gt; Seedling structure of &lt;i&gt;Euphorbia&lt;/i&gt; L. and &lt;i&gt;Chamaesyce&lt;/i&gt; Gray species &lt;/b&gt; - doi: 10.4025/actascibiolsci.v36i1.18601

Chamaesyce prostrata (Aiton) Small, Euphorbia heterophylla L. and Euphorbia graminea Jacq. are weedy species that occur with relative frequency in the region of Maringá, Paraná State, Brazil. Data about the morphology and anatomy of seedlings of these species were obtained, with emphasis on significant structural differences of seedlings between species of Euphorbia and Chamaesyce. Seedlings are phanerocotylar and epigeal. Root is axial and triarch. Cotyledons are leaf-like and dorsiventral. Eophylls and prophylls are simple and dorsiventral. Morphological variations occur in the cotyledon shape of Euphorbia seedlings. It is remarkable the Kranz structure of leaves that occurs only in Chamaesyce.

Mutations in the Arabidopsis RPK1 gene uncouple cotyledon anlagen and primordia by modulating epidermal cell shape and polarity.

SummaryPlant seedlings have either one or two cotyledons. The mechanisms that regulate this organ number are poorly understood. Mutations in the RECEPTOR-LIKE PROTEIN KINASE1 (RPK1) gene of the dicot Arabidopsis have only one cotyledon, with low penetrance due to complex genetic redundancy. An analysis of patterning genes required for cotyledon initiation showed that these have normal expression patterns, defining the cotyledon anlagen, in rpk1. This was also true for key genes, which organize the shoot apical meristem (SAM). By contrast, epidermal cell shape and polarity were compromised in rpk1 embryos, as evidenced by disturbed polarity of the auxin efflux carrier PIN1. PIN1 is required for the establishment of auxin maxima, which induce and maintain organ primordia. The effects in rpk1 mutants manifest in a spatially and timely stochastic fashion probably due to redundancy of RPK1-like functions. Consistently, auxin maxima showed a stochastic distribution in rpk1 embryos, being at times entirely absent and at other times supernumerary. This variability may explain how monocotyledonous seedlings and cotyledon shape variants can developmentally arise in Arabidopsis and possibly in other plants.

Early stages of leaf development in has mutant of Arabidopsis thaliana

The elucidation of molecular mechanisms underlying the leaf development can be facilitated by the detailed anatomical study of leaf development mutants. We present an analysis of leaf anatomy and morphogenesis during early developmental stages in has mutant of Arabidopsis thaliana. The recessive has mutation affects a number of aspects in plant development, including the shape and size of both cotyledons and leaves. The earliest developmental observations suggest almost synchronous growth of the first two leaf primordia of has mutant. No significant disruption of the cell division pattern in the internal tissue is observed at the earliest stages of development, with the major anatomical difference compared to wild type primordia being the untimely maturation of mesophyll tissue cells in has mutant. At the stage of leaf blade formation, structure disruption becomes clearly evident, by irregular arrangement of the cell layers and the lack of polarity in juvenile has leaves. One distinguishing feature of the mutant leaf anatomy is the absence of mesophyll tissue differentiation. Altered has mutant leaf morphology could be at least partially accounted for by the ectopic STM activity that was found at the base of leaf primordia during early stages of leaf development in has plants.

Variation in agro-morphological characteristics of cacao, Theobroma cacao L., in farmers' fields in Nigeria

Knowledge of available variability in a crop species provides a guide for the utilization and conservation of useful variation. Seventeen agro-morphological traits were studied in 184 accessions of cacao, Theobroma cacao L. collected from farmers' fields (138) and field genebank collections (46). Descriptive statistics—univariate analysis of variance (ANOVA)—were used to determine variation among accessions. Multivariate analysis with principal component analysis (PCA) was done and a cluster dendrogram was generated based on the unweighted pair group mean with arithmetic average (UPGMA). The first three principal component axes accounted for 43.6% of total variation observed among accessions studied. Quantitative bean traits—dry bean weight, nib weight, fresh weight, cotyledon length and cotyledon width—and qualitative fruit traits—basal constriction, apex form, ridge colour, fruit shape, flush colour and cotyledon shape—were the most important traits accounting for the variability observed. Six groups of accessions were obtained from cluster analysis. Fruit and bean traits of Upper Amazon Forasteros observed in farmers' accessions provided evidence of a shift from previously grown local ‘West African Amelonado’ from the Lower Amazon Forastero population. In conclusion, this study revealed some accessions with useful trait combinations in farmers' plantations and indicated a need to conserve the local ‘Amelonado’ landrace variety to avoid extinction and to preserve the unique flavour of ‘West African Amelonado’ in cocoa breeding programmes.

주요 광엽잡초 유묘의 형태적 특성을 기초로 한 간이 식별법

농경지에 발생하는 주요 잡초에 대한 유묘기 검색방법을 개발하기 위하여 주요 잡초 60종에 대한 양적, 질적형질을 조사하였다. 잡초 유묘를 동정하는 형질로는 질적형질이 양적형질에 비해 보다 더 유용하였다. 자엽의 형태는 타원형과 광타원형이 가장 많았다. 차풀과 큰메꽃은 자엽의 형태가 넓은 직사각형이었다. 자엽의 형태가 횡광타원형인 초종은 4종이었다. 취명아주 등 22종의 잡초는 자엽의 형태가 1개 이상이었다. 이 중 자엽의 형태가 3가지 이상인 초종은 4종으로서 마디풀과의 참소리쟁이와 여뀌 그리고 대극과의 애기땅빈대와 깨풀이었다. 새팥은 자엽이 지면아래의 종자 속에 남아 있었다. 자엽의 엽두는 원두가 가장 많았다. 자엽의 엽저는 쐐기저가 가장 많았다. 환삼덩굴과 마디풀은 자엽의 엽저가 무엽병저였다. 일부 초종은 제 1본엽기와 제 2본엽기때 본엽의 형태가 각각 상이한 경우도 있었다. 돌콩, 새팥 및 매듭풀은 제 1본엽이 각각 광란형, 심장형, 원형 또는 광도란형이었나 제 2본엽에서는 3초종 모두 3출엽으로 전개되었다. 그리고 자귀풀과 차풀은 제 1, 2본엽의 형태가 우수우상복엽이었다. 본엽의 가장자리는 주로 전연이었으나, 큰도꼬마리를 포함한 6종은 제 1, 2본엽의 엽연이 치상거치였다. 애기땅빈대는 제 1본엽의 엽연이 전연, 제 2본엽의 엽연이 치상거치였다. 명아주과의 흰명아주와 좀명아주의 엽연은 제 1본엽기에는 전연, 제 2본엽기에는 불규칙거치였다. 잡초 유묘 자엽의 양적형질은 질적형질에 비해 종 동정 시 활용도는 떨어지나 초종에 따라서는 매우 유용한 경우도 있었다. 농경지 주요 광엽잡초 유묘에 대한 자엽 및 본엽의 질적 형질을 이용하여 간이 식별법을 제시하였다. 식법법 작성 시 자엽의 형태가 1개 이상인 잡초종에 대해서는 각각의 자엽 형태를 이용하여 종 동정이 가능하도록 하였다. This study was conducted to develope identification method with major broad leaved weed seedlings. Characteristics of weed seedlings were investigated at two to four true leaf stage. Qualitative characteristics were more useful to identification of weed species than quantitative characteristics at the seedling stage. Many species were elliptic and broadly elliptic type in their cotyledon shape. Cotyledon shape of Cassia nomame and Calystegia sepium were broadly oblong. Four species were transverse broadly elliptic in their cotyledon shape. Rumex japonicus, Persicaria hydropiper, Euphorbia supina and Acalypha australis have three or more types in their cotyledon shape. Cotyledons of Vigna angularis var. nipponensis remained below ground after its germination. Many species were round in apex and were cuneate in base of cotyledon. Humulus japonicus and Polygonum aviculare were sessile in cotyledon base. The second true leaf shape of some species changed after first leaf stages. Glycine soja, V. angularis var. nipponensis and Kummerowia striata were broadly ovate, heart-shaped, orbicular or broadly obovate in their first true leaf, respectively, but the second true leaf shape of them were tripalmately compound. Aeschynomene indica and Cassia nomame were paripinnately compound leaf in their first and second true leaves. Margin of true leaves were entire in many species but six species including Xanthium occidentale were dentate in their true leaf margins. Margin of Euphorbia supina was entire in first true leaf and dentate in second true leaf. Margin of Chenopodium album and C. serotinum were entire in their first true leaf stage and erose in their second true leaf stage. The key for weed seedling identification of major weed species were made based on quantitative and qualitative morphological characteristics.

Mutation of the Membrane-Associated M1 Protease APM1 Results in Distinct Embryonic and Seedling Developmental Defects inArabidopsis

Aminopeptidase M1 (APM1), a single copy gene in Arabidopsis thaliana, encodes a metallopeptidase originally identified via its affinity for, and hydrolysis of, the auxin transport inhibitor 1-naphthylphthalamic acid (NPA). Mutations in this gene result in haploinsufficiency. Loss-of-function mutants show irregular, uncoordinated cell divisions throughout embryogenesis, affecting the shape and number of cotyledons and the hypophysis, and is seedling lethal at 5 d after germination due to root growth arrest. Quiescent center and cell cycle markers show no signals in apm1-1 knockdown mutants, and the ground tissue specifiers SHORTROOT and SCARECROW are misexpressed or mislocalized. apm1 mutants have multiple, fused cotyledons and hypocotyls with enlarged epidermal cells with cell adhesion defects. apm1 alleles show defects in gravitropism and auxin transport. Gravistimulation decreases APM1 expression in auxin-accumulating root epidermal cells, and auxin treatment increases expression in the stele. On sucrose gradients, APM1 occurs in unique light membrane fractions. APM1 localizes at the margins of Golgi cisternae, plasma membrane, select multivesicular bodies, tonoplast, dense intravacuolar bodies, and maturing metaxylem cells. APM1 associates with brefeldin A-sensitive endomembrane structures and the plasma membrane in cortical and epidermal cells. The auxin-related phenotypes and mislocalization of auxin efflux proteins in apm1 are consistent with biochemical interactions between APM1 and NPA.