Leaf Development and Vascular Differentiation

2021 ◽  
pp. 141-162
Author(s):  
Roni Aloni
Keyword(s):  
Leaf Development ◽  
Vascular Differentiation

The Role of Auxin in the Polar Organisation of Apical Meristems

1993 ◽  
Vol 20 (5) ◽  
pp. 541 ◽  
Author(s):  
T Sachs
Keyword(s):  
Leaf Development ◽  
Direct Contact ◽  
Cell Shape ◽  
Cellular Level ◽  
Vascular Differentiation ◽  
Pisum Sativum L ◽  
Stem Internode ◽  
Young Leaves ◽  
Lower Stem

Auxin is a correlative signal, coordinating leaf development with vascular differentiation and other developmental processes throughout the plant. It has a unique influence on the orientation of the differentiation of the cambium and its products. The problem considered was whether auxin has similar correlative roles in the development of meristematic stems. Seedlings of Pisum sativum L. were decapitated and the buds in the axil of the lower bract were used in all experiments. The lower stem internodes of these buds were ≤ 2 mm long and grew to about 50 mm in 6 d. The elongation of a stem internode continued even in the absence of all young leaves. However, vascular differentiation and transverse parenchyma growth correlated with the presence of developing leaves. Auxin replaced leaf effects on all stem tissues. The influence of both leaves and auxin were limited to the direction of the roots and to the sectors of the stem below the point of auxin application. This polarity differed from that of more mature tissues in requiring a direct contact with the roots. Another characteristic of minute stem internodes was that changes of orientation, expressed by cell shape and the axis of vascular differentiation, did not occur readily. However, at a narrow competence window local hormone applications did cause the formation of new stem-like axes. It is concluded that auxin is a correlative signal even within shoot apices and that the information it carries has an essential directional com- ponent. This directionality has not been studied at the cellular level.

scholarly journals Transcriptome Analysis of Ginkgo biloba L. Leaves across Late Developmental Stages Based on RNA-Seq and Co-Expression Network

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 315
Author(s):  
Hailin Liu ◽  
Xin Han ◽  
Jue Ruan ◽  
Lian Xu ◽  
Bing He
Keyword(s):  
Ginkgo Biloba ◽  
Leaf Development ◽  
Developmental Stages ◽  
Leaf Growth ◽  
Rna Seq ◽  
Final Size ◽  
Dioecious Species ◽  
Related Factors ◽  
New Genes ◽  
Gene Modules

The final size of plant leaves is strictly controlled by environmental and genetic factors, which coordinate cell expansion and cell cycle activity in space and time; however, the regulatory mechanisms of leaf growth are still poorly understood. Ginkgo biloba is a dioecious species native to China with medicinally and phylogenetically important characteristics, and its fan-shaped leaves are unique in gymnosperms, while the mechanism of G. biloba leaf development remains unclear. In this study we studied the transcriptome of G. biloba leaves at three developmental stages using high-throughput RNA-seq technology. Approximately 4167 differentially expressed genes (DEGs) were obtained, and a total of 12,137 genes were structure optimized together with 732 new genes identified. More than 50 growth-related factors and gene modules were identified based on DEG and Weighted Gene Co-expression Network Analysis. These results could remarkably expand the existing transcriptome resources of G. biloba, and provide references for subsequent analysis of ginkgo leaf development.

scholarly journals Genome-wide analysis of changes in miRNA and target gene expression reveals key roles in heterosis for Chinese cabbage biomass

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Peirong Li ◽  
Tongbing Su ◽  
Deshuang Zhang ◽  
Weihong Wang ◽  
Xiaoyun Xin ◽  
...  
Keyword(s):  
Chinese Cabbage ◽  
Leaf Development ◽  
Target Genes ◽  
Expression Patterns ◽  
Seedling Stage ◽  
Differentially Expressed ◽  
Small Rna Sequencing ◽  
Leaf Morphogenesis ◽  
Expression Levels ◽  
Parental Lines

AbstractHeterosis is a complex phenomenon in which hybrids show better phenotypic characteristics than their parents do. Chinese cabbage (Brassica rapa L. spp. pekinensis) is a popular leafy crop species, hybrids of which are widely used in commercial production; however, the molecular basis of heterosis for biomass of Chinese cabbage is poorly understood. We characterized heterosis in a Chinese cabbage F1 hybrid cultivar and its parental lines from the seedling stage to the heading stage; marked heterosis of leaf weight and biomass yield were observed. Small RNA sequencing revealed 63 and 50 differentially expressed microRNAs (DEMs) at the seedling and early-heading stages, respectively. The expression levels of the majority of miRNA clusters in the F1 hybrid were lower than the mid-parent values (MPVs). Using degradome sequencing, we identified 1,819 miRNA target genes. Gene ontology (GO) analyses demonstrated that the target genes of the MPV-DEMs and low parental expression level dominance (ELD) miRNAs were significantly enriched in leaf morphogenesis, leaf development, and leaf shaping. Transcriptome analysis revealed that the expression levels of photosynthesis and chlorophyll synthesis-related MPV-DEGs (differentially expressed genes) were significantly different in the F1 hybrid compared to the parental lines, resulting in increased photosynthesis capacity and chlorophyll content in the former. Furthermore, expression of genes known to regulate leaf development was also observed at the seedling stage. Arabidopsis plants overexpressing BrGRF4.2 and bra-miR396 presented increased and decreased leaf sizes, respectively. These results provide new insight into the regulation of target genes and miRNA expression patterns in leaf size and heterosis for biomass of B. rapa.

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