Loblolly pine seedling root anatomy and iron accumulation as affected by soil waterlogging

1987 ◽  
Vol 17 (10) ◽  
pp. 1257-1264 ◽  
Author(s):  
M. R. McKevlin ◽  
D. D. Hook ◽  
W. H. Mckee Jr. ◽  
S. U. Wallace ◽  
J. R. Woodruff
Keyword(s):  
Loblolly Pine ◽  
Cell Walls ◽  
Cortical Cell ◽  
Root Anatomy ◽  
Intercellular Spaces ◽  
Seedling Root ◽  
Aeration System ◽  
Pine Seedlings ◽  
Epidermal Surface ◽  
Bordered Pits

Loblolly pine seedlings were grown under flooded and drained conditions in a greenhouse pot study. Flooded roots developed aerenchyma tissue within the stele between the xylem poles, extending from the phloem outward to the pericycle. Large intercellular spaces were present in the pericyclic parenchyma within the phellogen of flooded woody roots. Flooded stems exhibited lenticel hypertrophy. Large intercellular spaces in the cortex were continuous with intercellular spaces in the pericyclic parenchyma of the root. Flooding of roots generally resulted in accumulation of Fe on the epidermal surface and in as well as between cortical cell walls inward to the endodermis. Fe accumulated in and between the precursor phloem cells and became more evident in the region of maturation. In roots with secondary thickening, little Fe was visible in the phloem but was present in helical secondary walls of tracheids. Fe also accumulated on and in bordered pits of root tracheids. Results suggest that flooded loblolly pine seedlings possess a limited internal aeration system and that diffusion of oxygen into the root system may be responsible for the presence of oxidized Fe within the stele.

scholarly journals The Association of a Longidorus Species with Stunting and Root Damage of Loblolly Pine (Pinus taeda L.) Seedlings

Plant Disease ◽  
2002 ◽  
Vol 86 (7) ◽  
pp. 803-807 ◽  
Author(s):  
Stephen W. Fraedrich ◽  
Michelle M. Cram
Keyword(s):  
Pinus Taeda ◽  
Loblolly Pine ◽  
Dry Weight ◽  
Forest Tree ◽  
Root Weight ◽  
Extraction Techniques ◽  
Seedling Root ◽  
Pine Seedlings ◽  
Proper Diagnosis ◽  
Pinus Taeda L

A Longidorus species was consistently associated with patches of stunted and chlorotic loblolly pine seedlings at a forest-tree nursery in Georgia. Seedlings from affected areas had poorly developed root systems that lacked lateral and feeder roots. Longidorus population densities in composite soil samples from the margins of patches ranged from 9 to 67 nematodes per 100 cm3 of soil. In a growth chamber experiment, seedling root dry weight decreased with respect to the initial Longidorus dose as well as the final Longidorus populations in containers. The dry root weight of seedlings were 0.117, 0.090, 0.066, and 0.065 g in containers initially infested with 0, 50, 100, and 200 Longidorus, respectively. Lateral and fine roots were lacking on seedlings at the highest doses. Populations of Longidorus increased in all containers during the experiment. Damage to loblolly pine seedlings caused by Longidorus is a previously undescribed problem in southern pine nurseries. Proper diagnosis of the problem by nematode testing laboratories may require the use of extraction techniques specific for larger nematodes such as Longidorus.

scholarly journals Use of anatomical root markers for species identification in Catasetum (Orchidaceae) at the Portal da Amazônia region, MT, Brazil

2015 ◽  
Vol 45 (1) ◽  
pp. 21-28 ◽  
Author(s):  
Ivone Vieira da SILVA ◽  
Rubens Maia de OLIVEIRA ◽  
Ana Aparecida Bandini ROSSI ◽  
Angelita Benevenuti da SILVA ◽  
Daiane Maia de OLIVEIRA
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Cortical Cell ◽  
Central Area ◽  
Digital Camera ◽  
Root Anatomy ◽  
Wall Thickening ◽  
Vascular Cylinder ◽  
Endodermal Cell ◽  
Mato Grosso

Orchidaceae is one of the largest botanical families, with approximately 780 genera. Among the genera of this family, Catasetum currently comprises 166 species. The aim of this study was to characterize the root anatomy of eight Catasetum species, verifying adaptations related to epiphytic habit and looking for features that could contribute to the vegetative identification of such species. The species studied were collected at the Portal da Amazônia region, Mato Grosso state, Brazil. The roots were fixed in FAA 50, cut freehand, and stained with astra blue/fuchsin. Illustrations were obtained with a digital camera mounted on a photomicroscope. The roots of examined species shared most of the anatomical characteristics observed in other species of the Catasetum genus, and many of them have adaptations to the epiphytic habit, such as presence of secondary thickening in the velamen cell walls, exodermis, cortex, and medulla. Some specific features were recognized as having taxonomic application, such as composition of the thickening of velamen cell walls, ornamentation of absorbent root-hair walls, presence of tilosomes, composition and thickening of the cortical cell walls, presence of mycorrhizae, endodermal cell wall thickening, the number of protoxylem poles, and composition and thickening of the central area of the vascular cylinder. These traits are important anatomical markers to separate the species within the genus and to generate a dichotomous identification key for Catasetum. Thus, providing a useful tool for taxonomists of this group

A histological comparison of fungal colonization in tomato seedlings susceptible or resistant to Fusarium crown and root rot disease

1988 ◽  
Vol 66 (5) ◽  
pp. 915-925 ◽  
Author(s):  
R. A. Brammall ◽  
V. J. Higgins
Keyword(s):  
Root Rot ◽  
Cell Walls ◽  
Dominant Gene ◽  
Cortical Cell ◽  
Fungal Colonization ◽  
Single Dominant Gene ◽  
Intercellular Spaces ◽  
Root Rot Disease ◽  
Crown And Root Rot ◽  
Rot Disease

Root colonization of tomato cultivars susceptible or resistant to Fusarium crown and root rot disease, caused by the pathogen Fusarium oxysporum f.sp. radicis-lycopersici Jarvis & Shoemaker, was studied histologically. In seedlings of susceptible cultivars ('Ohio MR13', 'Bonny Best', and 'Vendor') held at 22 °C, direct penetration of epidermal cells occurred by 24 h after inoculation and colonization of suberized hypodermal cells and adjacent intercellular spaces by 72 h. The cortex was colonized between 72 and 96 h after inoculation and the stele was commonly colonized by 120 to 144 h. Colonization of the cortex and stele was associated with the breakdown of parenchymatous cell walls and middle lamellae near fungal hyphae. In cultivars resistant by a single dominant gene ('CR6', 'Larma', and 'B82-865') colonization was similar to that in susceptible cultivars until 72 h after inoculation. By this time, papillae were abundant within hypodermal cells. Successful colonization of hypodermal sites was associated with the incorporation of phenolic or lignin-like materials and suberin within cell walls of the underlying cortex. These cortical wall modifications were paralleled by the deposition of electron-opaque material into cortical cell walls and middle lamellae and the production of finely granular bands around the peripheries of colonized intercellular spaces. Phenolic-containing structural defensive barriers (i.e., papillae and modified cortical cell walls) appear to be important in limiting fungal colonization in cultivars possessing single dominant gene resistance to this disease.

Morphological peculiarities of seeds of some species of the genus Epipactis Zinn. (Orchidaceae Juss.) of Ukrainian flora

2019 ◽  
Vol 11 (1) ◽  
pp. 93-100
Author(s):  
T Ljubka ◽  
O Tsarenko ◽  
I Tymchenko
Keyword(s):  
Seed Coat ◽  
Cell Walls ◽  
Morphological Study ◽  
Population Level ◽  
Intercellular Spaces ◽  
Different Populations ◽  
Periclinal Walls ◽  
High Degree ◽  
Shape And Size ◽  
Generative Organs

The investigation of macro- and micromorphological peculiarities of seeds of four species of genus Epipactis (Orchidaceae) of Ukrainian flora were carried out. The genus Epipactis is difficult in the in in taxonomic terms and for its representatives are characterized by polymorphism of morphological features of vegetative and generative organs of plants and ability of species to hybridize. The aim of the research was to perform a comparative morphological study of seeds of E. helleborine, E. albensis, E. palustris, E. purpurata and to determine carpological features that could more accurately identify species at the stage of fruiting. A high degree of variation in the shape of the seeds in different populations within the species and overlap of most quantitative carpological characteristics of studied species are noted. There were no significant differences in micromorphological features of the structure of the testa at species or population level. The reticulate surface of the testa is characteristic of all species, the cells of testa are mostly elongated, penta-hexagonal, individual cells almost isodiametric-pentagonal. From the micropillary to the chalasal end, a noticeable change in the shape and size of the seed coat cells is not observed. There are no intercellular spaces, the anticlinal walls of adjacent cells are intergrown and the boundaries between them become invisible. The outer periclinal walls have a single, mainly longitudinal thin ribbed thickenings. Anticlinal cell walls are thick, dense, smooth. The longitudinal Anticlinal walls are almost straight, transverse - straight or sometimes curved in some cells. Epicuticular deposits on the periclinal walls are absent. It is concluded that the use of macro and micromorphological characteristics of seeds of these species for clearer diagnosis at the stage of fruiting is low informative.

MICROSTRUCTURE ANALYSIS OF MOSO BAMBOO (Phyllostachys pubescens MAZEL) SURFACE AFTER UV RADIATION

2019 ◽  
Vol 27 (01) ◽  
pp. 1950090
Author(s):  
HAIXIA YU ◽  
XIN PAN ◽  
WEIMING YANG ◽  
WENFU ZHANG ◽  
XIAOWEI ZHUANG
Keyword(s):  
Uv Radiation ◽  
Cell Walls ◽  
Uv Light ◽  
Parenchyma Cell ◽  
Moso Bamboo ◽  
Thick Wall ◽  
Phyllostachys Pubescens ◽  
Thin Wall ◽  
Intercellular Spaces ◽  
Parenchyma Cell Walls

Bamboo material is widely used in outdoor applications. However, they are easily degraded when exposed to sunlight, their smooth surface will gradually turn to rough, and small cracks will appear and finally develop to large cracks. The paper presents a first-time investigation on the microstructure changes in the tangential section of Moso bamboo (Phyllostachys pubescens Mazel) radiated by artificial UV light. The results showed that the cracks mainly appeared at intercellular spaces of fibers where lignin content was high, the parenchyma cell walls and neighbor pits where the cell wall was very thin and more vulnerable than the other parts. In addition, the part of raised area and pit cavity tended to absorb more UV light radiation and showed more and larger cracks than the otherwhere. Cracks at the intercellular spaces of fibers were larger and bigger than those on the parenchyma cell walls. The cracks on the pits of the parenchyma cell walls normally appeared at one pit and then extended to the several surrounding pits. Bordered pits cavity showed more and larger cracks than the pits on the thin wall cells. The simple pits on the thick wall cells and the fiber cells were unaffected by UV radiation.

scholarly journals Histological studies on the development of Phoma root rot of alfalfa

1969 ◽  
Vol 89 (3-4) ◽  
pp. 251-262
Author(s):  
Rocío del P. Rodríguez
Keyword(s):  
Root Rot ◽  
Cell Walls ◽  
Enzymatic Degradation ◽  
Cortical Cell ◽  
Host Responses ◽  
Histological Studies ◽  
Tissue Degradation ◽  
Electron And Light Microscopy ◽  
Xylem Elements ◽  
Scanning Electron

Several stages of the disease cycle of root rot of alfalfa caused by Phoma medicaginis var. medicaginis were studied by using scanning electron and light microscopy. First activity of the pathogen was the external colonization of the root. The pathogen penetrated directly causing discoloration and tissue disintegration. Inter- and intracellular penetration facilitated by enzymatic degradation was likely the mechanism involved in breaching the barrier of the epidermal cells. Colonization of the cortex was intercellular. Radial access to the xylem elements was achieved through the cortex. Host responses to invasion by the pathogen were suberization of cortical cell walls and occlusion of vessels with pectic substances and wound gum. Cavities in the cortex resulting from tissue degradation were associated with later stages of infection. Intracellular hyphae were observed in dead cells of the cortex and in the xylem. 

Growth and gas exchange of loblolly pine seedlings as influenced by drought and air pollutants

1990 ◽  
Vol 51 (1-2) ◽  
pp. 105-116 ◽  
Author(s):  
Woong S. Lee ◽  
Boris I. Chevone ◽  
John R. Seiler
Keyword(s):  
Gas Exchange ◽  
Loblolly Pine ◽  
Air Pollutants ◽  
Pine Seedlings

scholarly journals Fungicides Improve Field Performance of Stored Loblolly and Longleaf Pine Seedlings

1996 ◽  
Vol 20 (1) ◽  
pp. 5-9 ◽  
Author(s):  
John C. Brissette ◽  
James P. Barnett ◽  
John P. Jones
Keyword(s):  
Loblolly Pine ◽  
Cold Storage ◽  
Untreated Control ◽  
Longleaf Pine ◽  
Field Performance ◽  
Storage Duration ◽  
Fungicide Application ◽  
Total Height ◽  
Pine Seedlings

Abstract Seedlings of loblolly and longleaf pine lifted in December, January, and February were treated with either benomyl or ridomil before cold storage. Along with an untreated control, they were planted after cold storage of less than 1 wk, 3 wk, and 6 wk. Survival was measured in mid-June after planting, and after 1 and 4 yr in the field. Total height was measured after 4 yr. The fungicide application increased survival of both species lifted in December or February and was beneficial to longleaf pine seedlings regardless of storage duration. Fungicide-treated longleaf pine seedlings had greater mean 4 yr height than the controls, but fungicides did not affect the height of loblolly pine. South. J. Appl. For. 20(1): 5-9.

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