The structure of Eucalypt roots

1976 ◽  
Vol 24 (5) ◽  
pp. 619 ◽  
Author(s):  
JT Tippett ◽  
TP O'Brien
Keyword(s):  
Comparative Study ◽  
Growth Rates ◽  
Phytophthora Cinnamomi ◽  
Root Systems ◽  
Root Anatomy ◽  
Age And Growth ◽  
First Order ◽  
Root Zones ◽  
Eucalypt Species ◽  
Finest Roots

The two eucalypt species Eucalyptus obliqua and E. st johnii differ in their susceptibility to Phytophthora cinnamomi, which infects their roots. A comparative study of the anatomy of the root systems of 12-week-old intermediate seedlings was made, the material used ranging in size from the finest roots to first order laterals. The root anatomy of the two species was similar but the species could be distinguished by differences in cortex persistence and in the rate of polyphenol accumulation. However, it was recognized that such differences were dependent on the age and growth rates of the roots sampled and could not be correlated with the differing susceptibilities of the two eucalypt species to Phytophthora cinnamomi. The walls of the exodermis and endodermis in both species are suberized and the ultrastructure of these walls was examined. Broad bands of suberized lamellae completely lined the exodermal cells in the zone of differentiation. In mature root zones the external radial walls of the epidermis were thickened and contained polyphenols. The roots which had commenced secondary thickening developed a specialized periderm, a polyderm, which consisted of alternating layers of suberized and non-suberized cells.

Invasion of Bassendean Dune Banksia Woodland by Phytophthora cinnamomi

1994 ◽  
Vol 42 (6) ◽  
pp. 725 ◽  
Author(s):  
TCJ Hill ◽  
JT Tippett ◽  
BL Shearer
Keyword(s):  
Infection Rate ◽  
Water Table ◽  
Phytophthora Cinnamomi ◽  
Root Systems ◽  
Aerial Photographs ◽  
Dune System ◽  
First Order ◽  
Top 40 ◽  
Banksia Attenuata ◽  
Upper Slope

The rate and mechanism of the spread of Phytophthora cinnamomi in Banksia woodland of the Bassendean Dune system north of Perth, Western Australia was studied. Aerial photographs were used to measure the spread of disease in fronts longer than 5 km over 35 years. Fronts in upper slope positions moved downhill and uphill at 1.01 and 1.13 m year-1, respectively, while fronts in low-lying positions moved downgrade and upgrade (with and against the direction of water table flow) at 1.30 and 1.20 m year-1, respectively. Fronts in low-lying areas spread significantly faster than those on upper slopes. Excavations to 2 m depth of the root systems of 21 dying plants of Banksia attenuata R.Br., an overstorey co-dominant, revealed that 28% (3.9 roots/tree) of all first-order roots were infected. Assessment of the proportion of roots infected revealed a significant (P < 0.01) departure from uniform distribution of disease down the profile in both upper slope and drained flat sites. In 14 trees on dune slopes, 6-40 m above the aquifer, infection rate was higher than expected in roots lying at 21-40 cm depth, but lower than expected in roots below 1 m. Seventy three percent of infected roots lay in the top 40 cm of soil. In seven trees on a drained flat, 2-3 m above the aquifer, infection rate was high in the 21-60 cm horizon and also in roots below 1 m. Even though Phytophthora cinnamomi was active in the vicinity of the water table in trees on drained flats, the slow, steady spread of the disease in all landscape positions suggested that the primary mode of fungal invasion was through roots of susceptible vegetation. No evidence was found of accelerated spread of disease caused by the dispersal of zoospores.

scholarly journals Comparative Study of Chemical Stability of Two H1Antihistaminic Drugs, Terfenadine and ItsIn VivoMetabolite Fexofenadine, Using LC-UV Methods

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Anna Gumieniczek ◽  
Anna Berecka-Rycerz ◽  
Rafał Pietraś ◽  
Izabela Kozak ◽  
Karolina Lejwoda ◽  
...  
Keyword(s):  
Comparative Study ◽  
Chemical Stability ◽  
First Order ◽  
First Order Kinetics ◽  
Kinetics Of Degradation ◽  
Effects Of Temperature ◽  
High Doses ◽  
Antihistaminic Drugs ◽  
Kinetics Of

A comparative study of chemical stability of terfenadine (TER) and itsin vivometabolite fexofenadine (FEX) was performed. Both TER and FEX were subjected to high temperature at different pH and UV/VIS light at different pH and then quantitatively analyzed using new validated LC-UV methods. These methods were used to monitor the degradation processes and to determine the kinetics of degradation for both the compounds. As far as the effects of temperature and pH were concerned, FEX occurred more sensitive to degradation than TER. As far as the effects of UV/VIS light and pH were concerned, the both drugs were similarly sensitive to high doses of light. Using all stress conditions, the processes of degradation of TER and FEX followed the first-order kinetics. The results obtained for these two antihistaminic drugs could be helpful in developing their new derivatives with higher activity and stability at the same time.

Population structure, age and growth rates of conifer species and their relation to environmental variables at Malam Jabba, Swat District, Pakistan

2018 ◽  
Vol 31 (2) ◽  
pp. 429-441
Author(s):  
Arsalan ◽  
Muhammad Faheem Siddiqui ◽  
Moinuddin Ahmed ◽  
Syed Shahid Shaukat ◽  
Alamdar Hussain
Keyword(s):  
Population Structure ◽  
Growth Rates ◽  
Environmental Variables ◽  
Age And Growth ◽  
Conifer Species

scholarly journals <sup>210</sup>Pb-<sup>226</sup>Ra chronology reveals rapid growth rate of <i>Madrepora oculata</i> and <i>Lophelia pertusa</i> on world's largest cold-water coral reef

2012 ◽  
Vol 9 (3) ◽  
pp. 1253-1265 ◽  
Author(s):  
P. Sabatier ◽  
J.-L. Reyss ◽  
J. M. Hall-Spencer ◽  
C. Colin ◽  
N. Frank ◽  
...  
Keyword(s):  
Growth Rate ◽  
Coral Reef ◽  
Metal Oxides ◽  
Growth Rates ◽  
Cold Water ◽  
Age And Growth ◽  
Lophelia Pertusa ◽  
Fe Oxide ◽  
Oxide Contamination ◽  
Water Coral

Abstract. Here we show the use of the 210Pb-226Ra excess method to determine the growth rate of two corals from the world's largest known cold-water coral reef, Røst Reef, north of the Arctic circle off Norway. Colonies of each of the two species that build the reef, Lophelia pertusa and Madrepora oculata, were collected alive at 350 m depth using a submersible. Pb and Ra isotopes were measured along the major growth axis of both specimens using low level alpha and gamma spectrometry and trace element compositions were studied. 210Pb and 226Ra differ in the way they are incorporated into coral skeletons. Hence, to assess growth rates, we considered the exponential decrease of initially incorporated 210Pb, as well as the increase in 210Pb from the decay of 226Ra and contamination with 210Pb associated with Mn-Fe coatings that we were unable to remove completely from the oldest parts of the skeletons. 226Ra activity was similar in both coral species, so, assuming constant uptake of 210Pb through time, we used the 210Pb-226Ra chronology to calculate growth rates. The 45.5 cm long branch of M. oculata was 31 yr with an average linear growth rate of 14.4 ± 1.1 mm yr−1 (2.6 polyps per year). Despite cleaning, a correction for Mn-Fe oxide contamination was required for the oldest part of the colony; this correction corroborated our radiocarbon date of 40 yr and a mean growth rate of 2 polyps yr−1. This rate is similar to the one obtained in aquarium experiments under optimal growth conditions. For the 80 cm-long L. pertusa colony, metal-oxide contamination remained in both the middle and basal part of the coral skeleton despite cleaning, inhibiting similar age and growth rate estimates. The youngest part of the colony was free of metal oxides and this 15 cm section had an estimated a growth rate of 8 mm yr−1, with high uncertainty (~1 polyp every two to three years). We are less certain of this 210Pb growth rate estimate which is within the lowermost ranges of previous growth rate estimates. We show that 210Pb-226Ra dating can be successfully applied to determine the age and growth rate of framework-forming cold-water corals if Mn-Fe oxide deposits can be removed. Where metal oxides can be removed, large M. oculata and L. pertusa skeletons provide archives for studies of intermediate water masses with an up to annual time resolution and spanning over many decades.

Effects of Temperature on Root Morphology and Ectendomycorrhizal Development in Pinusresinosa Ait.

1975 ◽  
Vol 5 (2) ◽  
pp. 171-175 ◽  
Author(s):  
Hugh E. Wilcox ◽  
Ruth Ganmore-Neumann
Keyword(s):  
Root Growth ◽  
Root System ◽  
Root Morphology ◽  
Root Systems ◽  
Second Order ◽  
Root Temperature ◽  
First Order ◽  
Effects Of Temperature

Seedlings of Pinusresinosa were grown at root temperatures of 16, 21 and 27 °C, both aseptically and after inoculation with the ectendomycorrhizal fungus BDG-58. Growth after 3 months was significantly influenced by the presence of the fungus at all 3 temperatures. The influence of the fungus on root growth was obscured by the effects of root temperature on morphology. The root system at 16 and at 21 °C possessed many first-order laterals with numerous, well developed second-order branches, but those at 27 °C had only a few, relatively long, unbranched first-order laterals. Although the root systems of infected seedlings were larger, the fungus increased root growth in the same pattern as determined by the temperature.

scholarly journals Age, growth, and recruitment patterns of juvenile ladyfish (Elopssp) from the east coast of Florida (USA)

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1392
Author(s):  
Juan C. Levesque
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Age And Growth ◽  
Growth Equation ◽  
Length Frequency ◽  
Daily Growth ◽  
Exponential Regression ◽  
Absolute Growth ◽  
Specific Growth Rates ◽  
Size At Age

Ladyfish (Elopssp) are a common and economically valuable coastal nearshore species found along coastal beaches, bays, and estuaries of the southeastern United States, and subtropical and tropical regions worldwide. Previously, ladyfish were a substantial bycatch in Florida’s commercial fisheries, but changes in regulations significantly reduced commercial landings. Today, ladyfish are still taken in commercial fisheries in Florida, but many are also taken by recreational anglers. Life-history information and research interest in ladyfish is almost non-existent, especially information on age and growth. Thus, the overarching purpose of this study was to expand our understanding of ladyfish age and growth characteristics. The specific objectives were to describe, for the first time, age, growth, and recruitment patterns of juvenile ladyfish from the east coast of Florida (USA). In the Indian River Lagoon (IRL), annual monthly length-frequency distributions were confounded because a few small individuals recruited throughout the year; monthly length-frequency data generally demonstrated a cyclical pattern. The smallest were collected in September and the largest in May. Post-hoc analysis showed no significant difference in length between August and May, or among the other months. In Volusia County (VC), annual monthly length-frequency distribution demonstrated growth generally occurred from late-winter and spring to summer. The smallest ladyfish were collected in February and the largest in August. On average, the absolute growth rate in the IRL was 36.3 mm in 60 days or 0.605 mm day−1. Cohort-specific daily growth rates, elevations, and coincidentals were similar among sampling years. Cohort-specific growth rates ranged from 1.807 in 1993 to 1.811 mm day−1in 1994. Overall, growth was best (i.e., goodness of fit) described by exponential regression. On average, the absolute growth rate in VC was 28 mm in 150 days or 0.1866 mm day−1. Cohort-specific daily growth rates were significantly different among sampling years; however, the elevations and coincidentals were similar. Cohort-specific growth rates ranged from 1.741 in 1994 to 1.933 mm day−1in 1993. Mean ladyfish growth was best described by linear regression; however, natural growth was explained better by exponential regression. In the IRL, the corrected exponential growth equation yielded a size-at-age 1 of 156.0 mm SL, which corresponded to an estimated growth rate of 0.4356 mm day−1. In VC, the corrected exponential growth equation yielded a size-at-age 1 of 80 mm SL corresponding to an estimated growth rate of 0.2361 mm day−1.

Mercury Concentration of White Muscle in Relation to Age, Growth, and Condition in Four Species of Fishes from Clay Lake, Ontario

1974 ◽  
Vol 31 (11) ◽  
pp. 1723-1729 ◽  
Author(s):  
D. P. Scott
Keyword(s):  
Mercury Concentration ◽  
White Muscle ◽  
Species Differences ◽  
Lake Ontario ◽  
Age And Growth ◽  
Coregonus Clupeaformis ◽  
Catostomus Commersoni ◽  
First Order ◽  
Species Area ◽  
Statistical Relationships

Studies of large (about 125) samples of walleye (Stizostedion vitreum), northern pike (Esox lucius), white sucker (Catostomus commersoni), and lake whitefish (Coregonus clupeaformis) from each of four areas of Clay Lake, Ontario, a highly mercury-contaminated lake, have confirmed previous findings that the larger the fish, the greater the white muscle mercury concentration, within species, within populations. This relationship was statistically broken into separate age:concentration and growth:concentration partial regressions; older fish and faster growing fish were generally more contaminated, subject to the above species–area restrictions. However, the generally positive correlation between concentration and condition (as measured by relative heaviness of individuals within area–species samples) found in the previous study is here contradicted; relatively heavier fish tended to have lower Hg concentrations. Despite the relatively small size of the lake (about 11 × 2 km) analyses of multiple covariance indicated profound within-species differences between the samples from the four areas. However, there did not appear to be any obvious correlation between these differences and sediment mercury values.The various statistical relationships do not appear to be simple, first-order regressions; rather, there appear to be significant interactions between age and growth, and age and condition, which tend to change the partial slopes with age. The four species were distinctly different in most of their relationships.

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