Tissue Structure Changes of Aquilaria sinensis Xylem after Fungus Induction

In this study, we analyzed the mechanism and the process of fungal-induced agarwood formation in Aquilaria sinensis and studied the functional changes in the xylem structure after the process. The microscopic structure of the white zone, transition zone, agarwood zone, and decay zone of 12-and 18-months of inoculation A. sinensis xylem was studied. The distribution of nuclei, starch grains, soluble sugars, sesquiterpenes, fungal propagules, and mycelium in xylem tissues was investigated by histochemical analysis. The results show that the process of agarwood formation was accompanied by apoptosis of parenchyma cells such as interxylary phloem, xylem rays, and axial parenchyma. Regular changes in the conversion of starch grains to soluble sugars, the production of sesquiterpenoids, and other characteristic components of agarwood in various types of parenchyma cells were also observed. The material transformation was concentrated in the interxylary phloem, providing a structural and material basis for the formation of agarwood. It is the core part of the production of sesquiterpenoids and other characteristic products of agarwood. Compared with the A. sinensis inoculated for 12 months, the xylem of the A. sinensis inoculated for 18 months was more vigorous. There were no significant differences between the 12 and 18 months of inoculation in terms of sugars and agarwood characteristic products. In production, harvesting after 12 months of inoculation can improve harvesting efficiency.

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The occurrence and development of intraxylary phloem in young Aquilaria sinensis shoots

IAWA Journal ◽

10.1163/22941932-40190221 ◽

2019 ◽

Vol 40 (1) ◽

pp. 23-42

Author(s):

Bei Luo ◽

Tomoya Imai ◽

Junji Sugiyama ◽

Jian Qiu

Keyword(s):

Growth Period ◽

Maturation Stage ◽

Aquilaria Sinensis ◽

Callose Deposition ◽

Active Growth ◽

Primary Xylem ◽

Parenchyma Cells ◽

Interxylary Phloem ◽

Sieve Tubes ◽

Sieve Plates

ABSTRACT Agarwoods such as Aquilaria spp. and Gyrinops spp. (Thymelaeaceae) produce interxylary phloem in their secondary xylem and intraxylary phloem at the periphery of the pith, facing the primary xylem. We studied young shoots of Aquilaria sinensis and characterized the development of its intraxylary phloem. It was initiated by the division of parenchyma cells localized in the outer parts of the ground meristem immediately following the maturation of first-formed primary xylem. Its nascent sieve plates bore donut-like structures, the individual pores of which were so small (less than 0.1 μm) that they were hardly visible under FE-SEM. Intraxylary phloem developed into mature tissue by means of the division and proliferation of parenchyma cells. During the shoots’ active growth period, the sieve pore sizes were 0.1–0.5 μm, with tubular elements passing through them. In the maturation stage, large clusters of sieve tubes continued to be differentiated in the intraxylary phloem. In the partial senescence stage observed in a three-centimeter-diameter branch, intraxylary phloem cells in the adaxial part became crushed, and sieve plates had pores over 1–2 μm in diameter without any callose deposition. Before and after the differentiation of interxylary phloem in the first and second internodes, callose staining detected more than twice as many sieve tubes in intraxylary phloem than in external phloem. However, after differentiation of interxylary phloem in the eleventh internode, more sieve tubes were found in interxylary phloem than in intraxylary and external phloem. This suggests that prior to the initiation of interxylary phloem intraxylary phloem acts as the principal phloem. After its differentiation, however, interxylary phloem takes over the role of principal phloem. Interxylary phloem thus acts as the predominant phloem in the translocation of photosynthates in Aquilaria sinensis.

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Regeneration of vascular tissue through redifferentiation of interxylary phloem after complete girdling in Aquilaria sinensis

IAWA Journal ◽

10.1163/22941932-bja10065 ◽

2021 ◽

pp. 1-16

Author(s):

Bei Luo ◽

Arata Yoshinaga ◽

Tatsuya Awano ◽

Keiji Takabe ◽

Takao Itoh

Keyword(s):

Time Course ◽

Potential Role ◽

Vascular Tissue ◽

Secondary Xylem ◽

Vascular Cambium ◽

Aquilaria Sinensis ◽

Phloem Fibers ◽

Interxylary Phloem ◽

Time Course Study

Abstract We studied the time-course of stem response for six months following complete girdling in branches of Aquilaria sinensis to determine the potential role of interxylary phloem (IP) in this response. It was found that the vascular cambium, as well as its derivative secondary xylem and phloem, regenerated fully through redifferentiation of IP. We confirmed that vascular cambium regenerated within one month after girdling based on observation of new vessels, IP, and secondary phloem fibers. The time-course study showed that IPs made connections with each other, merged, and became larger through the proliferation of IPs parenchyma cells and the cleaving of secondary xylem in a narrow zone 400 to 1000 μm deep inside the girdled edge. This led to the formation of a complete circular sheath of vascular cambium, followed by the regeneration of vascular tissue. It is worth noting that the secondary xylem is regenerated always following the formation of a thick belt of wound xylem.

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Interxylary phloem and xylem rays are the structural foundation of agarwood resin formation in the stems of Aquilaria sinensis

Trees ◽

10.1007/s00468-018-1799-4 ◽

2018 ◽

Vol 33 (2) ◽

pp. 533-542 ◽

Cited By ~ 2

Author(s):

Peiwei Liu ◽

Xingli Zhang ◽

Yun Yang ◽

Chun Sui ◽

Yanhong Xu ◽

...

Keyword(s):

Structural Foundation ◽

Aquilaria Sinensis ◽

Interxylary Phloem ◽

Agarwood Resin

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Bacillus pumilus, a Novel Ginger Rhizome Rot Pathogen in China

Plant Disease ◽

10.1094/pdis-12-12-1178-re ◽

2013 ◽

Vol 97 (10) ◽

pp. 1308-1315 ◽

Cited By ~ 12

Author(s):

Qin Peng ◽

Yihui Yuan ◽

Meiying Gao

Keyword(s):

Molecular Biology ◽

Bacillus Pumilus ◽

Shandong Province ◽

Gram Positive ◽

Disease Symptoms ◽

Starch Grains ◽

First Report ◽

Ginger Rhizome ◽

Parenchyma Cells ◽

Rhizome Rot

Ginger rhizome rot is a major factor limiting the yield and marketability of ginger in Shandong Province, China. In order to identify the pathogen causing ginger rhizome rot, evaluate its pathogenicity, and explore its pathogenesis, diseased ginger rhizomes and surrounding soils were collected. A gram-positive, spore-forming, rod-shaped bacterium, designated GR8, was frequently isolated from the ginger rhizome samples. The bacterium was identified as Bacillus pumilus based on physio-biochemical and molecular biology characteristics. Pathogenicity studies with GR8 showed that it could cause disease of the tested rhizomes slices and the entire rhizome when wounded but no disease occurred when the rhizome was not wounded. Preliminary pathogenicity studies demonstrated that cell-free cultures of GR8 could not cause any disease symptoms, whereas the bacterial suspensions caused severe symptoms. The pathology studies revealed that infection of GR8 could cause starch grains to shrink from normal size, and destroy the parenchyma cells by invading and propagating in them. This is the first report of B. pumilus causing ginger rhizome rot.

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The Fine Structure of the Wheat Scutellum During Germination

Australian Journal of Biological Sciences ◽

10.1071/bi9720469 ◽

1972 ◽

Vol 25 (3) ◽

pp. 469 ◽

Cited By ~ 21

Author(s):

JG Swift ◽

TP O'brien

Keyword(s):

Electron Microscopy ◽

Fine Structure ◽

Epithelial Cells ◽

Light And Electron Microscopy ◽

Cell Types ◽

Wall Material ◽

Cytological Evidence ◽

Starch Grains ◽

Parenchyma Cells ◽

Cytological Changes

The cytological changes that take place in the scutellar epithelium and parenchyma during the first 5 days of germination are described by light and electron microscopy. Within 6 hr small starch grains appear in the plastids of both cell types and the size and number of starch grains increase gradually as germination proceeds. Later in germination starch disappears again from the plastids in the epithelial cells, but large starch grains still remain in the parenchyma cells. The reserves of the protein bodies are hydrolysed and the residual vacuoles undergo extensive coales-cence. Modifications in the appearance of the wall material of the epithelial cells as these cells elongate are illustrated and possible functional bases for these changes are suggested. The cells of the scutellar epithelium show no cytological evidence for their known functions of diastase secretion and nutrient absorption.

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Morphology and biochemical characteristics of pistils in the staminate flowers of yellow horn during selective abortion

Australian Journal of Botany ◽

10.1071/bt11210 ◽

2012 ◽

Vol 60 (2) ◽

pp. 143 ◽

Cited By ~ 3

Author(s):

Yan Zhou ◽

Shumin Gao ◽

Xiaofang Zhang ◽

Hua Gao ◽

Qing Hu ◽

...

Keyword(s):

Soluble Sugars ◽

Normal Activity ◽

High Ratio ◽

Gas Chromatography Mass Spectrometry ◽

Endogenous Hormones ◽

Starch Grains ◽

Biochemical Characteristics ◽

Pistil Abortion ◽

Biochemical Assays ◽

Pistil Development

Yellow horn (Xanthoceras sorbifolia Bunge), an andromonoecious woody plant, has both hermaphrodite and staminate flowers. Both stamens and pistils in hermaphrodite flowers develop normally, but the pistils are aborted and the stamens develop normally in staminate flowers. To investigate the anatomical and biochemical characteristics of the aborted pistils in staminate flowers, anatomical and biochemical assays were carried out. Microstructure, ultrastructure and their histochemistry were analysed. The hypotheses that amylase and endogenous hormones are involved in pistil abortion were tested by comparing the homochronous pistil tissues in both hermaphrodite and staminate flowers. We conclude that pistil abortion occurs at the meiosis stage of megasporocyte cells and programmed cell death in staminate flowers. Simultaneously, we observed that starch grains and protein abundance are of benefit to megasporocyte meiosis. Our study indicates that the low activity of amylase isozymes α3 and α4 will result in insufficient soluble sugars for pistil development. The endogenous hormones gibberellic acid (GA3) and abscisic acid (ABA) in the pistil of both staminate and hermaphrodite flowers at four stages were measured by gas chromatography–mass spectrometry. The results suggested that both ABA and GA3 are related to pistil abortion. In addition, a high ratio of GA3 and ABA exists in the stage of megasporocyte cells until the stage of megasporocyte meiosis I, which affects the normal activity of sucrose invertase and pistil development in staminate flowers. These results suggest that starch grains, proteins and endogenous hormones are important for pistil development and, as well, that pistil abortion in staminate flowers is related to the level of endogenous hormones and the activity of amylase isozymes.

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Plastids features and transfer cells occurrence in the phloem of Portulaca mucronata and P. hirsutissima (Portulacaceae)

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.1995.019 ◽

2014 ◽

Vol 64 (2) ◽

pp. 149-153 ◽

Cited By ~ 1

Author(s):

Maria E. Maranhão Estelita ◽

Tereza C. Marinho

Keyword(s):

Cell Wall ◽

Secondary Cell Wall ◽

Transfer Cells ◽

Leaf Structure ◽

Primary Cell Wall ◽

Starch Grains ◽

Kranz Anatomy ◽

Phloem Parenchyma ◽

Serra Do Cipó ◽

Parenchyma Cells

The species of the Portulacaceae of the Serra do Cipó, State of Minas Gerais, Brasil, were studied. In Portulaca mucronata and P. hirsutissima transfer cells are companion and phloem parenchyma cells; they have the same secondary cell wall features, that is, short papillate protuberances which are uniformly distributed around the primary cell wall. These features are similar in both species but they are very distinct from others referred in the literature; this could be useful in Taxonomy. The phloem plastids have a globular protein crystalloid, surrounded by proteinaceous filaments. In P. hirsutissima few starch grains may also be present, and this occurrence is considered primitive in the phylogenetic scale. These features agree with presumptive evolution of those of leaf structure: P. hirsutissima has C3 photosynthesis structure, and P. mucronata C4 or Kranz anatomy.

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Characterization of ground parenchyma cells in Moso bamboo (Phyllostachys edulis–Poaceae)

IAWA Journal ◽

10.1163/22941932-bja10076 ◽

2021 ◽

pp. 1-9

Author(s):

Caiping Lian ◽

Hong Chen ◽

Shuqin Zhang ◽

Rong Liu ◽

Zhihui Wu ◽

...

Keyword(s):

Three Dimensional ◽

Environmental Scanning Electron Microscopy ◽

Moso Bamboo ◽

Dimensional Structure ◽

Environmental Scanning ◽

Wall Thickening ◽

Phyllostachys Edulis ◽

Starch Grains ◽

Parenchyma Cells ◽

Quantitative Basis

Abstract Ground parenchyma cells play a crucial role in the growth and the mechanical properties of bamboo plants. Investigation of the morphology of ground parenchyma cells is essential for understanding the physiological functions andmechanical properties of these cells. This study aimed to characterize the anatomical structure of bamboo ground parenchyma cells and provide a qualitative and quantitative basis for the more effective utilization of bamboo. To do this, the morphology of ground parenchyma cells in Moso bamboo (Phyllostachys edulis) was studied using light microscopy and field-emission environmental scanning electron microscopy. Results show that various geometric shapes of ground parenchyma cells were observed, including nearly circular, square, long, oval, and irregular shapes. Cell walls of both long and short parenchyma cells exhibited primary wall thickening and secondary wall thickening, resulting in a primary pit field and simple pits. Most long cells were strip-shaped (L/W = 2.52), while most short cells were short and wide (L/W = 0.59). The proportion of long cells was 11 times greater than that of short cells. Most long cells were filled with starch grains, and some short cells also occasionally had starch grains. These findings allowed the first construction of the three-dimensional structure of parenchyma cells.

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Histochemistry of Paraquat Treated Wood in Azadirachta Indica A.Juss.

IAWA Journal ◽

10.1163/22941932-90000794 ◽

1983 ◽

Vol 4 (4) ◽

pp. 249-254 ◽

Cited By ~ 1

Author(s):

M. N. B. Nair ◽

J. J. Shah

Keyword(s):

Acid Phosphatase ◽

Succinate Dehydrogenase ◽

Azadirachta Indica ◽

Treated Wood ◽

Heartwood Formation ◽

Starch Grains ◽

Parenchyma Cells ◽

Ray Parenchyma ◽

Ray Parenchyma Cells ◽

Accumulation Of Lipids

Paraquat (1, 1'-dimethyl-4, 4' bipyridilium salt) induced heartwood formation in Azadirachta indica. The wood at the site of treatment showed desiccation. The induced heartwood is observed even at the height of 3 to 3.5 metres from the site of the treatment. Histochemical studies showed disappearance of starch grains and accumulation of lipids, insoluble polysaccharides and phenolics in the treated wood. The axial and ray parenchyma cells at the sapwood-heartwood boundary in the treated wood showed enhanced acid phosphatase, ATPase and succinate dehydrogenase activities. Traumatic gum ducts were also observed in the treated wood.

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CAMBIAL VARIANT AND XYLEM STRUCTURE IN THE STEM OF COCCULUS HIRSUTUS (MENISPERMACEAE)

IAWA Journal ◽

10.1163/22941932-90000345 ◽

2003 ◽

Vol 24 (4) ◽

pp. 411-420 ◽

Cited By ~ 7

Author(s):

Kishore S. Rajput ◽

K.S. Rao

Keyword(s):

Vascular Bundles ◽

Growth Rings ◽

Xylem Structure ◽

Vessel Elements ◽

Parenchyma Cells ◽

Ray Cells ◽

Cambial Variant ◽

Stem Development ◽

Cambial Cells ◽

Cocculus Hirsutus

Development of cambial variant and xylem structure were studied in the stem of Cocculus hirsutus (Menispermaceae). In the early stages of stem development several collateral vascular bundles are joined by interfascicular cambium resulting in the formation of a complete cambial cylinder. After functioning for two to three years the cambial ring ceases its activity. Subsequently a second ring of cambium is formed from the innermost cortical parenchyma cells. These parenchyma cells undergo periclinal divisions to give rise to cells that become lignified, abaxially, and cambial cells, adaxially. The cambial cells divide periclinally giving rise to individual vascular bundles with xylem and phloem. Later the cambium in each bundle is joined by interfascicular cambium. Subsequent cambia develop similarly resulting in the formation of successive rings of xylem and phloem. During the leafless condition, all the cambial rings are dormant, and flanked by mature xylem and phloem elements. With the sprouting of new leaves, either the existing outermost cambium reactivates or an entire new ring of cambium develops. The xylem is diffuseporous with indistinct growth rings. It is composed of fibre-tracheids, tracheids, vessel elements, libriform fibres, and parenchyma cells. Xylem rays are multiseriate, compound and heterocellular. Deformed libriform fibres and vessel elements commonly occur among the ray cells in all the successive rings of xylem. The length of fibres and the height and width of xylem rays increase gradually from the centre towards the periphery of the stem.

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