Seasonal changes in the physical nature of the bark phloem parenchyma cells ofPinus strobus

PROTOPLASMA ◽  
1960 ◽  
Vol 52 (2) ◽  
pp. 223-229 ◽  
Author(s):  
Johnson Parker
IAWA Journal ◽  
2003 ◽  
Vol 24 (4) ◽  
pp. 421-428
Author(s):  
Wei-Min Tian ◽  
Zheng-Hai Hu

The distribution pattern of vegetative storage proteins is reported for the first time for 18 species and 2 varieties of twelve genera of Rosaceae. Vegetative storage proteins were present in all the species studied of Prunoideae and absent in Maloideae. Their occurrence in a genus seemed to be either universal or entirely absent. Rosaceae trees were poor in vegetative storage proteins and the form of vegetative storage proteins was not protein body-like. Granular and floccular forms of vegetative storage proteins could be distinguished exclusively in the secondary phloem parenchyma cells and their distribution was cell-specific. Our results suggest that the distribution of vegetative storage proteins in Rosaceae can be considered as a taxonomically diagnostic feature. The nature of the bark proteins with seasonal changes in apple trees is discussed.


Author(s):  
Patrick Echlin ◽  
Thomas Hayes ◽  
Clifford Lai ◽  
Greg Hook

Studies (1—4) have shown that it is possible to distinguish different stages of phloem tissue differentiation in the developing roots of Lemna minor by examination in the transmission, scanning, and optical microscopes. A disorganized meristem, immediately behind the root-cap, gives rise to the vascular tissue, which consists of single central xylem element surrounded by a ring of phloem parenchyma cells. This ring of cells is first seen at the 4-5 cell stage, but increases to as many as 11 cells by repeated radial anticlinal divisions. At some point, usually at or shortly after the 8 cell stage, two phloem parenchyma cells located opposite each other on the ring of cells, undergo an unsynchronized, periclinal division to give rise to the sieve element and companion cell. Because of the limited number of cells involved, this developmental sequence offers a relatively simple system in which some of the factors underlying cell division and differentiation may be investigated, including the distribution of diffusible low atomic weight elements within individual cells of the phloem tissue.


1986 ◽  
Vol 64 (1) ◽  
pp. 85-89 ◽  
Author(s):  
Maria-Ivone C. Henriques ◽  
Fernando S. Henriques

Thin sections of malva (Malva sp.) leaves collected in the field and showing mottle and vein-clearing symptoms were examined by electron microscopy. Cytoplasmic inclusions typical of potyvirus and consisting of pinwheels, laminated aggregates, and scrolls were readily observed. In addition, rhabdoviruslike particles were also seen in the perinuclear space of phloem parenchyma cells and within membranous sacs scattered throughout the cytoplasm of other vascular bundle cells. Occasionally rhabdoparticles could be found embedded in an amorphous electron-dense body located within the cell vacuole. The rhabdovirus particles, approximately 75 × 300 nm, were bound by a membrane with outer projections and had an inner core displaying cross striations. The cytoplasm of infected mesophyll cells had chloroplasts containing large amorphous inclusion bodies and had extensive membranous tubules that were frequently associated with the potyvirus inclusions. These ultrastructural aspects, the size of the particles, and the data on host range indicate that malva plants under study were doubly infected by viruses which were tentatively identified as malva vein-clearing virus and a previously undescribed rhabdovirus.


1979 ◽  
Vol 57 (12) ◽  
pp. 1340-1344 ◽  
Author(s):  
Thompson Demetrio Pizzolato ◽  
David L. Regehr

An aqueous spray of 4-(2,4-dichlorophenoxy)butyric acid (2,4-DB) induces anatomical changes in young Glycine internodes. Four days after spraying, the first symptoms appear outside the cambium when the interfascicular parenchyma cells and the adjacent cortical parenchyma cells enlarge and divide in several planes. Four days later, the metaphloem parenchyma cells in many of the leaf traces undergo considerable periclinal cell division and extensive radial cell enlargement. The phloem parenchyma cells of the late metaphloem and first secondary phloem enlarge and divide in a less orderly fashion. Fifteen days after treatment, the cortical parenchyma is modified into a band of radially seriate cells above the protophloem fibers. Products of this cambium-like region convert the cortex into a callus-like tissue. The size of starch grains is reduced initially in the phloem and xylem and later in the cortex. It appears that the stimuli produced by 2,4-DB move into the internode via the metaphloem of leaf traces. Despite the rapid obliteration of conducting phloem by the 2,4-DB induced stimulation of phloem parenchyma, an accelerated differentiation of secondary phloem compensates for this loss.


IAWA Journal ◽  
1991 ◽  
Vol 12 (1) ◽  
pp. 51-56 ◽  
Author(s):  
Ji-lin Wu ◽  
Bing-zhong Hao

The secondary phloem in the trunk and branchlet of three species in Meliaceae, Swietenia macrophylla L., Chukrasia talularis A. Juss. and Melia azedarach L., was examined using light microscopy and electron microscopy. The vacuole protein bodies are found in most of the phloem parenchyma cells except companion cells. The protein nature of the bodies was demonstrated by the mercury - bromophenol blue reaction and enzymatic digestion with pepsin. Electronmicroscopical observations show that the protein bodies are electron-dense granules in central vacuoles. In the terminal branchlet, the protein bodies are extremely abundant before flushing in spring and most of them disappear in the inner phloem after flushing. This suggests that the vacuole protein bodies have a storage function.


Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2952
Author(s):  
Tuula Jyske ◽  
Katsushi Kuroda ◽  
Susanna Keriö ◽  
Andrey Pranovich ◽  
Riikka Linnakoski ◽  
...  

To understand the positional and temporal defense mechanisms of coniferous tree bark at the tissue and cellular levels, the phloem topochemistry and structural properties were examined after artificially induced bark defense reactions. Wounding and fungal inoculation with Endoconidiophora polonica of spruce bark were carried out, and phloem tissues were frequently collected to follow the temporal and spatial progress of chemical and structural responses. The changes in (+)-catechin, (−)-epicatechin, stilbene glucoside, and resin acid distribution, and accumulation patterns within the phloem, were mapped using time-of-flight secondary ion mass spectrometry (cryo-ToF-SIMS), alongside detailed structural (LM, TEM, SEM) and quantitative chemical microanalyses of the tissues. Our results show that axial phloem parenchyma cells of Norway spruce contain (+)-catechins, the amount of which locally increases in response to fungal inoculation. The preformed, constitutive distribution and accumulation patterns of (+)-catechins closely follow those of stilbene glucosides. Phloem phenolics are not translocated but form a layered defense barrier with oleoresin compounds in response to pathogen attack. Our results suggest that axial phloem parenchyma cells are the primary location for (+)-catechin storage and synthesis in Norway spruce phloem. Chemical mapping of bark defensive metabolites by cryo-ToF-SIMS, in addition to structural and chemical microanalyses of the defense reactions, can provide novel information on the local amplitudes and localizations of chemical and structural defense mechanisms and pathogen–host interactions of trees.


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