scholarly journals Primary Root and Mesocotyl Elongation in Maize Seedlings: Two Organs with Antagonistic Growth below the Soil Surface

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1274
Author(s):  
Mery Nair Sáenz Rodríguez ◽  
Gladys Iliana Cassab
Keyword(s):  
Higher Plants ◽  
Primary Root ◽  
Soil Surface ◽  
Early Embryo ◽  
Residual Soil ◽  
Differential Growth ◽  
Ancient Agriculture ◽  
Primary Roots ◽  
Mesocotyl Elongation ◽  
Response To Water

Maize illustrates one of the most complex cases of embryogenesis in higher plants that results in the development of early embryo with distinctive organs such as the mesocotyl, seminal and primary roots, coleoptile, and plumule. After seed germination, the elongation of root and mesocotyl follows opposite directions in response to specific tropisms (positive and negative gravitropism and hydrotropism). Tropisms represent the differential growth of an organ directed toward several stimuli. Although the life cycle of roots and mesocotyl takes place in darkness, their growth and functions are controlled by different mechanisms. Roots ramify through the soil following the direction of the gravity vector, spreading their tips into new territories looking for water; when water availability is low, the root hydrotropic response is triggered toward the zone with higher moisture. Nonetheless, there is a high range of hydrotropic curvatures (angles) in maize. The processes that control root hydrotropism and mesocotyl elongation remain unclear; however, they are influenced by genetic and environmental cues to guide their growth for optimizing early seedling vigor. Roots and mesocotyls are crucial for the establishment, growth, and development of the plant since both help to forage water in the soil. Mesocotyl elongation is associated with an ancient agriculture practice known as deep planting. This tradition takes advantage of residual soil humidity and continues to be used in semiarid regions of Mexico and USA. Due to the genetic diversity of maize, some lines have developed long mesocotyls capable of deep planting while others are unable to do it. Hence, the genetic and phenetic interaction of maize lines with a robust hydrotropic response and higher mesocotyl elongation in response to water scarcity in time of global heating might be used for developing more resilient maize plants.

Primary Root Elongation Rate and Abscisic Acid Levels of Maize in Response to Water Stress

Crop Science ◽  
2011 ◽  
Vol 51 (1) ◽  
pp. 157-172 ◽  
Author(s):  
Kristen A. Leach ◽  
Lindsey G. Hejlek ◽  
Leonard B. Hearne ◽  
Henry T. Nguyen ◽  
Robert E. Sharp ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Root Elongation ◽  
Primary Root ◽  
Elongation Rate ◽  
Root Elongation Rate ◽  
Response To Water

Early Pinus caribaea var. hondurensis root development. 2. Influence of soil strength

1996 ◽  
Vol 36 (7) ◽  
pp. 847 ◽  
Author(s):  
A Costantini ◽  
D Doley ◽  
HB So
Keyword(s):  
Root Development ◽  
Soil Type ◽  
Root Elongation ◽  
Primary Root ◽  
High Strength ◽  
Soil Strength ◽  
Shoot Development ◽  
Pinus Caribaea ◽  
Primary Shoot ◽  
Primary Roots

The influence of penetration resistance (PR), an easily measured indicator of soil strength, on the growth of Pinus caribaea var. hondurensis radicles and seedlings was investigated. Negative exponential relationships between PR and both radicle and primary root elongation were observed. All root elongation ceased at PR levels of 3.25 MPa. Tip diameters of radicles and primary roots were positively correlated with PR values up to 2.4 MPa, whilst numbers of primary roots, total root lengths and lengths of longest roots were all negatively correlated with PR. Hypocotyl elongation was also reduced by increasing PR, although the reductions occurred at higher PRs than those which inhibited root development. In contrast, primary shoot development was unaffected by PR levels which were sufficient to stop root elongation, but was reduced in soil with a PR of 4.8 MPa. There were significant family x soil type and family x PR interactions for radicle, hypocotyl, primary root and primary shoot development. 1f these interactions are correlated with performance in the field, then they may serve as useful indicators of family suitability to both soil type and high strength soils.

scholarly journals Plastid-Localized EMB2726 Is Involved in Chloroplast Biogenesis and Early Embryo Development in Arabidopsis

2021 ◽  
Vol 12 ◽  
Author(s):  
Chuanling Li ◽  
Jian-Xiu Shang ◽  
Chenlei Qiu ◽  
Baowen Zhang ◽  
Jinxue Wang ◽  
...  
Keyword(s):  
Chloroplast Development ◽  
Developmental Process ◽  
Higher Plants ◽  
Critical Role ◽  
Elongation Factor ◽  
Early Embryo ◽  
The Body ◽  
Insertion Mutant ◽  
Cell Stage ◽  
Dna Insertion

Embryogenesis is a critical developmental process that establishes the body organization of higher plants. During this process, the biogenesis of chloroplasts from proplastids is essential. A failure in chloroplast development during embryogenesis can cause morphologically abnormal embryos or embryonic lethality. In this study, we isolated a T-DNA insertion mutant of the Arabidopsis gene EMBRYO DEFECTIVE 2726 (EMB2726). Heterozygous emb2726 seedlings produced about 25% albino seeds with embryos that displayed defects at the 32-cell stage and that arrested development at the late globular stage. EMB2726 protein was localized in chloroplasts and was expressed at all stages of development, such as embryogenesis. Moreover, the two translation elongation factor Ts domains within the protein were critical for its function. Transmission electron microscopy revealed that the cells in emb2726 embryos contained undifferentiated proplastids and that the expression of plastid genome-encoded photosynthesis-related genes was dramatically reduced. Expression studies of DR5:GFP, pDRN:DRN-GFP, and pPIN1:PIN1-GFP reporter lines indicated normal auxin biosynthesis but altered polar auxin transport. The expression of pSHR:SHR-GFP and pSCR:SCR-GFP confirmed that procambium and ground tissue precursors were lacking in emb2726 embryos. The results suggest that EMB2726 plays a critical role during Arabidopsis embryogenesis by affecting chloroplast development, possibly by affecting the translation process in plastids.

scholarly journals The effect of nitrogen on the root and shoot development of Lolium multiflorum var. westerwoldicum.

1974 ◽  
Vol 22 (2) ◽  
pp. 82-88
Author(s):  
J.J. Schuurman ◽  
L. Knot
Keyword(s):  
Water Consumption ◽  
Lolium Multiflorum ◽  
Soil Surface ◽  
Root Surface ◽  
Root Surface Area ◽  
Primary Roots ◽  
Inner Diameter ◽  
N Rates ◽  
Soil Level ◽  
Secondary Roots

Westerwolds ryegrass was grown in tubes on artificial soil profiles at N rates equivalent to 25, 50 or 100 kg/ha with a water table maintained 70 cm below the soil surface. Average results/plant after 13 weeks at low and high N were: DM yield of tops 5.0 and 14.6 g, water consumption 2660 and 4850 cm2, DM yield of roots 1.4 and 3.4 g, total length of all primary roots 2589 and 3374 cm, number of primary roots 103 and 161, number of secondary roots in topsoil 63 and 83 and in subsoil 71 and 83, and total root surface area 1084 and 1736 cm2. ADDITIONAL ABSTRACT: L. multiflorum plants were grown on sandy soil in asbestos tubes with an inner diameter of 15 cm, and 75 cm high, and supplied with 25, 50 or 100 kg N/ha. The soil water level was maintained at 70 cm below soil level. Top growth 8 and 13 weeks after sowing was progressively enhanced by the 2 higher rates, weight increments amounting to at least 72 and 188 %, respectively. These growth increases were accompanied by augmented water consumption, as well as root growth and numbers. (Abstract retrieved from CAB Abstracts by CABI’s permission)

LOP1: a gene involved in auxin transport and vascular patterning in Arabidopsis

Development ◽  
1996 ◽  
Vol 122 (6) ◽  
pp. 1811-1819 ◽  
Author(s):  
F.M. Carland ◽  
N.A. McHale
Keyword(s):  
Cell Expansion ◽  
Higher Plants ◽  
Lateral Roots ◽  
Primary Root ◽  
Vascular Patterning ◽  
Basipetal Transport ◽  
Leaf Mutant ◽  
Identification And Characterization ◽  
Axial Growth

We have taken a genetic approach to understanding the mechanisms that control vascular patterning in the leaves of higher plants. Here we present the identification and characterization of the lop1 mutant of Arabidopsis which is defective in basipetal transport of IAA. Mutant leaf midveins show disoriented axial growth, and bifurcation into twin veins that are frequently rotated out of the normal dorsal/ventral axis of the leaf. Mutant plants also display abnormal patterns of cell expansion in the midrib cortex and in the epidermis of the elongation zone of lateral roots. Lateral roots show abnormal curvature during initiation, sometimes encircling the primary root prior to growth in a normal downward direction. Mutant seedlings have normal levels of free IAA, and appear normal in auxin perception, suggesting that transport is the primary lesion. The abnormalities in vascular development, lateral root initiation and patterns of cell expansion observed in the lop] mutant are consistent with a basic disruption in basipetal transport of IAA.

scholarly journals Some Mechanisms Modulating the Root Growth of Various Wheat Species under Osmotic-Stress Conditions

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1545
Author(s):  
Nina V. Terletskaya ◽  
Tamara E. Lee ◽  
Nazira A. Altayeva ◽  
Nataliya O. Kudrina ◽  
Irina V. Blavachinskaya ◽  
...  
Keyword(s):  
Osmotic Stress ◽  
Water Deficit ◽  
Apical Meristem ◽  
Primary Root ◽  
Triticum Aestivum L ◽  
Root Diameter ◽  
Wheat Species ◽  
Drought Tolerant ◽  
Primary Roots ◽  
Species Specific

The role of the root in water supply and plant viability is especially important if plants are subjected to stress at the juvenile stage. This article describes the study of morphophysiological and cytological responses, as well as elements of the anatomical structure of primary roots of three wheat species, Triticum monococcum L., Triticum dicoccum Shuebl., and Triticum aestivum L., to osmotic stress. It was shown that the degree of plasticity of root morphology in water deficit affected the growth and development of aboveground organs. It was found that in conditions of osmotic stress, the anatomical root modulations were species-specific. In control conditions the increase in absolute values of root diameter was reduced with the increase in the ploidy of wheat species. Species-specific cytological responses to water deficit of apical meristem cells were also shown. The development of plasmolysis, interpreted as a symptom of reduced viability apical meristem cells, was revealed. A significant increase in enzymatic activity of superoxide dismutase under osmotic stress was found to be one of the mechanisms that could facilitate root elongation in adverse conditions. The tetraploid species T. dicoccum Shuebl. were confirmed as a source of traits of drought tolerant primary root system for crosses with wheat cultivars.

scholarly journals RNA-Seq Transcriptome Analysis of Rice Primary Roots Reveals the Role of Flavonoids in Regulating the Rice Primary Root Growth

Genes ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 213
Author(s):  
Yu Xu ◽  
Junjie Zou ◽  
Hongyan Zheng ◽  
Miaoyun Xu ◽  
Xuefeng Zong ◽  
...  
Keyword(s):  
Cell Wall ◽  
Root Growth ◽  
Primary Root ◽  
Glutathione Metabolism ◽  
Auxin Signaling ◽  
Antioxidant Enzyme Activities ◽  
Rna Seq ◽  
Root Tips ◽  
Primary Roots ◽  
Quercetin Treatment

Flavonoids play important roles in root development and in its tropic responses, whereas the flavonoids-mediated changes of the global transcription levels during root growth remain unclear. Here, the global transcription changes in quercetin-treated rice primary roots were analyzed. Quercetin treatment significantly induced the inhibition of root growth and the reduction of H2O2 and O2− levels. In addition, the RNA-seq analysis revealed that there are 1243 differentially expressed genes (DEGs) identified in quercetin-treated roots, including 1032 up-regulated and 211 down-regulated genes. A gene ontology (GO) enrichment analysis showed that the enriched GO terms are mainly associated with the cell wall organization, response to oxidative stress, and response to hormone stimulus. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment pathway analysis showed that the enriched DEGs are involved in phenylpropanoid biosynthesis, glutathione metabolism, and plant hormone signal transduction. Moreover, the quercetin treatment led to an increase of the antioxidant enzyme activities of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) in rice roots. Also, the quercetin treatment altered the DR5:GUS expression pattern in the root tips. All of these data indicated that the flavonoids-mediated transcription changes of genes are related to the genes involved in cell wall remodeling, redox homeostasis, and auxin signaling, leading to a reduced cell division in the meristem zone and cell elongation in the elongation zone of roots.

scholarly journals AtNSE1 and AtNSE3 are required for embryo pattern formation and maintenance of cell viability during Arabidopsis embryogenesis

2019 ◽  
Vol 70 (21) ◽  
pp. 6229-6244
Author(s):  
Gang Li ◽  
Wenxuan Zou ◽  
Liufang Jian ◽  
Jie Qian ◽  
Jie Zhao
Keyword(s):  
Cell Death ◽  
Cell Viability ◽  
Cell Fate ◽  
Embryo Development ◽  
Higher Plants ◽  
Early Embryo ◽  
Embryo Cell ◽  
Early Embryogenesis ◽  
Embryo Abortion ◽  
Cell Fate Decisions

Abstract Embryogenesis is an essential process during seed development in higher plants. It has previously been shown that mutation of the Arabidopsis non-SMC element genes AtNSE1 or AtNSE3 leads to early embryo abortion, and their proteins can interact with each other directly. However, the crucial regions of these proteins in this interaction and how the proteins are cytologically involved in Arabidopsis embryo development are unknown. In this study, we found that the C-terminal including the Ring-like motif of AtNSE1 can interact with the N-terminal of AtNSE3, and only the Ring-like motif is essential for binding with three α motifs of AtNSE2 (homologous to AtMMS21). Using genetic assays and by analysing molecular markers of cell fate decisions (STM, WOX5, and WOX8) in mutant nse1 and nse3 embryos, we found that AtNSE1 and AtNSE3 work non-redundantly in early embryo development, and that differentiation of the apical meristem and the hypophysis fails in the mutants, which have disrupted auxin transportation and responses. However, the upper cells of the suspensor in the mutants seem to have proper embryo cell identity. Cytological examination showed that cell death occurred from the early embryo stage, and that vacuolar programmed cell death and necrosis in the nse1 and nse3 mutant embryos led to ovule abortion. Thus, AtNSE1 and AtNSE3 are essential for maintaining cell viability and growth during early embryogenesis. Our results improve our understanding of the functions of SMC5/6 complex in early embryogenesis in Arabidopsis.

GERMINATION, GROWTH AND DEVELOPMENT OF COMMON MILKWEED

1978 ◽  
Vol 58 (2) ◽  
pp. 493-498 ◽  
Author(s):  
PRASANTA C. BHOWMIK
Keyword(s):  
Lateral Roots ◽  
Seedling Emergence ◽  
Primary Root ◽  
Germination Percentage ◽  
Asclepias Syriaca ◽  
Seed Collection ◽  
Primary Roots ◽  
Number Of Leaves ◽  
Primary Root Length ◽  
Storage Temperatures

Germination percentage of common milkweed (Asclepias syriaca L.) seeds was low 1 mo after seed collection. Seed dormancy decreased with time at storage temperatures of −12°, 5° or 21 °C. After 11 months of storage, seeds stored at 21 °C had 15–18% higher germination compared to the seeds stored at −12° and 5 °C. The best seedling emergence was obtained at a temperature of 27 °C when seeds were planted at a depth of 0.5 or 1 cm. Seedling emergence was better in muck or sandy soil than in clay soil. Seedlings developed slowly up to 30 days after emergence at 15 °C under an 8-, 12- or 16-h photoperiod. High temperatures (27 °C) stimulated seedling growth under each photoperiod. Taller seedlings with more leaves, longer primary roots, more lateral roots and adventitious root buds grew at 27 °C as compared to 15° or 21 °C. Increasing the photoperiod from 8 to 16 h increased plant height and number of leaves but not primary root length.

Embryo development, megagametophyte storage product accumulation, and seed efficiency in Taxus brevifolia

2001 ◽  
Vol 31 (6) ◽  
pp. 1046-1056 ◽  
Author(s):  
Erika D Anderson ◽  
John N Owens
Keyword(s):  
Early Embryo ◽  
Light Limitation ◽  
Leaf Axil ◽  
Differential Growth ◽  
Taxus Brevifolia ◽  
Pollination Success ◽  
Early Embryos ◽  
Poor Seed ◽  
Embryo Stage ◽  
Incomplete Cleavage

Taxus brevifolia Nutt. has a reduced ovulate structure that consists of a single ovule in a leaf axil instead of a compound ovulate strobilus. Taxus brevifolia on southern Vancouver Island, British Columbia, were studied over three seasons. Proembryos occurred from mid-May to mid-June. They underwent four free nuclear divisions forming 16 nuclei before cellularization. Early embryos were present from mid-May to mid-August. Simple polyembryony was observed up to the massive embryo stage, and differential growth of the embryonal cells was interpreted as incomplete cleavage polyembryony. Mid-embryos were present from mid-June to late August and had a distinct protoderm and focal zone. Late embryos were visible from mid-July onwards. Carbohydrates began accumulating at the early embryo stage, whereas proteins and lipids accumulated in the late embryo stage. The presence of a red aril corresponded to increased amounts of lipid in the megagametophyte cells. Individual seeds matured from July until November. The seed efficiency ranged from 0 to 16% and averaged 5%. Prezygotic loss was the most common fate of ovules, followed by postzygotic loss. Possible causes of this poor seed efficiency are poor pollination success, insect damage, or light limitation.

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