Role of weeds in the management of nitrogen in a young Pinus radiata plantation

New Forests ◽  
1989 ◽  
Vol 3 (3) ◽  
pp. 203-224 ◽  
Author(s):  
P. J. Smethurst ◽  
E. K. S. Nambiar
Keyword(s):  
Pinus Radiata

scholarly journals No carbon limitation after lower crown loss in Pinus radiata

2020 ◽  
Vol 125 (6) ◽  
pp. 955-967 ◽  
Author(s):  
Mireia Gomez-Gallego ◽  
Nari Williams ◽  
Sebastian Leuzinger ◽  
Peter Matthew Scott ◽  
Martin Karl-Friedrich Bader
Keyword(s):  
Pinus Radiata ◽  
Carbon Limitation ◽  
C Storage ◽  
Abiotic Stressors ◽  
Crown Defoliation ◽  
Foliar Pathogens ◽  
The Impact ◽  
C Assimilation ◽  
Genotype A

Abstract Background and Aims Biotic and abiotic stressors can cause different defoliation patterns within trees. Foliar pathogens of conifers commonly prefer older needles and infection with defoliation that progresses from the bottom crown to the top. The functional role of the lower crown of trees is a key question to address the impact of defoliation caused by foliar pathogens. Methods A 2 year artificial defoliation experiment was performed using two genotypes of grafted Pinus radiata to investigate the effects of lower-crown defoliation on carbon (C) assimilation and allocation. Grafts received one of the following treatments in consecutive years: control–control, control–defoliated, defoliated–control and defoliated–defoliated. Results No upregulation of photosynthesis either biochemically or through stomatal control was observed in response to defoliation. The root:shoot ratio and leaf mass were not affected by any treatment, suggesting prioritization of crown regrowth following defoliation. In genotype B, defoliation appeared to impose C shortage and caused reduced above-ground growth and sugar storage in roots, while in genotype A, neither growth nor storage was altered. Root C storage in genotype B decreased only transiently and recovered over the second growing season. Conclusions In genotype A, the contribution of the lower crown to the whole-tree C uptake appears to be negligible, presumably conferring resilience to foliar pathogens affecting the lower crown. Our results suggest that there is no C limitation after lower-crown defoliation in P. radiata grafts. Further, our findings imply genotype-specific defoliation tolerance in P. radiata.

The Role of Phytophthora cryptogea and Waterlogging in a Decline of Pinus radiata

1976 ◽  
Vol 24 (6) ◽  
pp. 703 ◽  
Author(s):  
M Bumbieris
Keyword(s):  
Pinus Radiata ◽  
Phytophthora Cryptogea ◽  
Presence And Absence

Experiments to determine the roles of Phytophthora cryptogea and waterlogging in a decline of Pinus radiata showed that the fungus affected young pines up to 1 year old when associated with water- logged soil. In drier soil, similar plants were affected by the fungus only when they had originally been transplanted to the test pots. However, waterlogging affected both transplanted and non-trans- planted young trees in both the presence and absence of the fungus. Thus waterlogging is an important factor in the decline of young Pinus radiata. A similar situation probably exists with regard to older trees growing on very wet sites.

Effect of Photoperiod, Night Temperature, and Frost Incidence on Development of Frost Hardiness in Pinus radiata

1982 ◽  
Vol 9 (3) ◽  
pp. 333 ◽  
Author(s):  
DH Greer ◽  
IJ Warrington
Keyword(s):  
Pinus Radiata ◽  
Frost Hardiness ◽  
Late Winter ◽  
Controlled Environment ◽  
Night Temperature ◽  
Specific Effects ◽  
Critical Photoperiod ◽  
Simulated Climate ◽  
Temperature Hardening

The role of photoperiod, night temperature, and frequency and severity of frosts on the development of frost hardiness in seedlings of Pinus radiata was studied using controlled environment treatments. In one experiment the specific effects of 9 and 14 h photoperiods and 5 and 15°C night temperatures were examined. In a second experiment, seedlings were sequentially hardened under two simulated early autumn to late winter climates, with the photoperiod and day/night temperatures progressively altered at 11 and 21 day intervals respectively. In addition, half of the seedlings raised in each simulated climate were exposed concurrently to a conditioning frost regime. Frost hardiness of the seedlings in each sequence was determined at regular intervals using a series of evaluation frosts. Frosts of between -3 and -5°C were the most effective factor in controlling the development of frost hardiness. Night temperatures as low as 1°C were also effective but not those above 5°C. A minimum photoperiod requirement of less than 11 h for up to 42 days exposure was required for low-temperature hardening. There appeared to be a response lag in the development of frost hardiness once the critical photoperiod and inductive night temperatures had been imposed. Differences between nursery sites in frost hardiness of seedling stock were attributed to differences in their environments, particularly the incidence of frosts. The final maximum frost hardiness varied between the treatments from - 7.5 to -19°C indicating that Pinus radiata has a greater potential to develop frost hardiness than was previously thought from field observations.

The role of Pityophthorus spp. as vectors of pitch canker affecting Pinus radiata

2007 ◽  
Vol 139 (6) ◽  
pp. 864-871 ◽  
Author(s):  
Joyce M. Sakamoto ◽  
Thomas R. Gordon ◽  
Andrew J. Storer ◽  
David L. Wood
Keyword(s):  
Relative Humidity ◽  
Pinus Radiata ◽  
Low Temperatures ◽  
Native Species ◽  
Field Experiments ◽  
Infection Frequency ◽  
Pitch Canker ◽  
Monterey Pine ◽  
Canker Pathogen

AbstractThe fungus Fusarium circinatum Nirenberg and O’Donnell (Hypocreaceae) causes pitch canker, a disease affecting pines worldwide. In California, many native insect species have been implicated in transmission of F. circinatum. This study showed that two twig beetle species, Pityophthorus setosus Blackman and Pityophthorus carmeli Swaine (Coleoptera: Curculionidae: Corthylini), can make wounds on healthy Monterey pine (Pinus radiata D. Don (Pinaceae)) branches that are suitable for infection by the pitch canker pathogen. Because these two species are not known to engage in maturation feeding and the observed wounds were not associated with tunneling, we hypothesize that the wounds reflect “exploratory tasting” to assess the suitability of the substrate for colonization. This behavior would help to explain how twig beetles can serve as wounding agents on healthy host branches, which are not amenable to colonization by these insects. We tested two specific hypotheses: (1) two native species of Pityophthorus can create wounds on F. circinatum-contaminated trees that are sufficient for development of disease; and (2) the efficiency with which F. circinatum infects beetle wounds is affected by relative humidity. Under growth-chamber conditions, both Pityophthorus species indulged in exploratory behavior that caused wounds suitable for development of pitch canker. Field experiments did not confirm a significant effect of beetle activity on infection frequency, perhaps because of an overall low infection rate due to low temperatures. Experiments conducted under controlled conditions documented a significant effect of relative humidity on the success rate of twig beetle-initiated infections.

ASSOCIATION BETWEEN A NATIVE SPITTLEBUG (HOMOPTERA: CERCOPIDAE) ON MONTEREY PINE AND AN INTRODUCED TREE PATHOGEN WHICH CAUSES PITCH CANKER DISEASE

1998 ◽  
Vol 130 (6) ◽  
pp. 783-792 ◽  
Author(s):  
Andrew J. Storer ◽  
David L. Wood ◽  
Karen R. Wikler ◽  
Thomas R. Gordon
Keyword(s):  
Pinus Radiata ◽  
Spore Suspension ◽  
Field Observations ◽  
Pitch Canker ◽  
Canker Disease ◽  
Feeding Sites ◽  
Monterey Pine ◽  
Canker Pathogen ◽  
Monterey Peninsula

AbstractJuvenile Monterey pines, Pinus radiata D. Don (Pinaceae), in a native stand on the Monterey Peninsula, California, exhibited wilted green shoots in the spring of 1996. The pitch canker fungus, Fusarium subglutinans (Wollenweb. & Reinking) P.E. Nelson, Toussoun & Marasas f.sp. pini, was subsequently isolated from 95% of these shoots. Spittle masses produced by Aphrophora canadensis Walley were observed on the symptomless shoots of many of these trees. The pitch canker fungus was isolated from the feeding sites of this insect on 55% of symptomless shoots, and from shoot sections adjacent to these feeding sites on 29% of the shoots. Shoots with spittlebugs feeding on them in May 1996 were more likely to develop pitch canker disease by September 1996 and March 1997 than shoots without spittlebugs. Shoots with spittle masses in March 1997 were as likely to develop pitch canker disease by May and August 1997 as shoots without spittle masses, but the origin of the infection was most likely where A. canadensis feeding had taken place. In a controlled test, the incidence of pitch canker on shoots of potted Monterey pines was dependent on the presence of a spittlebug and a spore suspension of the pathogen. Thus, both field observations and controlled studies show an association between native A. canadensis and the introduced pitch canker pathogen. The role of A. canadensis in the epidemiology of pitch canker disease remains to be determined.

Role of dactinomycin in the improved survival of children with Wilms' tumor

JAMA ◽  
1966 ◽  
Vol 195 (12) ◽  
pp. 1005-1009 ◽  
Author(s):  
D. J. Fernbach
Keyword(s):  
Wilms Tumor

Role of the allergist in diagnosis and management of patients with uveitis

JAMA ◽  
1966 ◽  
Vol 195 (3) ◽  
pp. 167-172 ◽  
Author(s):  
T. E. Van Metre
Keyword(s):  
Diagnosis And Management
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