The decomposition of green leaf litter is less temperature sensitive than that of senescent leaf litter: An incubation study

Dissolved organic matter (DOM) is a critical part of the global carbon cycle. Currently, it is understood that at least a portion of the chromophoric DOM (CDOM) character can be described through an electronic interaction of charge transfer (CT) complexes. While much work has been done to understand the influence of CT on soil and aquatic reference standard DOM, little is known about the influence of CT in fresh terrestrially derived DOM. In this study, leaf litter leachates from three tree species were treated (reduced) with sodium borohydride to determine the contribution of CT on a source of fresh terrestrial DOM. Leaf litter was sampled four times through decomposition under natural (field) conditions to determine the influence of degradation on response to borohydride treatment. Leaf litter CDOM displayed a unique loss of UVB absorption following borohydride treatment, as well as a homogenizing effect on fluorescence emission character. Humification index (HIX) differentiated Elliot Soil Humic Acid and Suwannee River Fulvic Acid from leaf litter leachates. However, biological index (BIX), and spectral slope metrics were not able to differentiate leaf leachates from these reference standards. Apparent quantum yields were similar in magnitude between leaf leachates and reference standards, although leaf leachate spectra displayed features not evident in reference standards. These results help understand the origins of DOM optical properties and associated quantitative indices in freshly sourced terrestrial material. Overall, these results suggest that even at the initial stages of decomposition, terrestrial CDOM exhibits optical characteristics and responses to removal of electron accepting ketones and aldehydes, through borohydride treatment, similar to more processed CDOM.

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Allelopathic effects of Solidago canadensis L. between the leaf litter and green leaf

Allelopathy Journal ◽

10.26651/2017-41-2-1095 ◽

2017 ◽

Vol 41 (2) ◽

pp. 189-200

Author(s):

J.F. Sun ◽

◽

Y .L. Liao ◽

W.W. Zhang ◽

H. Zhang ◽

...

Keyword(s):

Leaf Litter ◽

Green Leaf ◽

Solidago Canadensis ◽

Allelopathic Effects

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Transmission of Phytophthora ramorum in Mixed-Evergreen Forest in California

Phytopathology ◽

10.1094/phyto-95-0587 ◽

2005 ◽

Vol 95 (5) ◽

pp. 587-596 ◽

Cited By ~ 207

Author(s):

Jennifer M. Davidson ◽

Allison C. Wickland ◽

Heather A. Patterson ◽

Kristen R. Falk ◽

David M. Rizzo

Keyword(s):

Leaf Litter ◽

Disease Transmission ◽

Rainy Season ◽

Forest Type ◽

Phytophthora Ramorum ◽

Green Leaf ◽

Evergreen Forest ◽

Infested Soil ◽

Live Oak ◽

Dispersal Distances

During 2001 to 2003, the transmission biology of Phytophthora ramorum, the causal agent of sudden oak death, was studied in mixedevergreen forest, a common forest type in northern, coastal California. Investigation of the sources of spore production focused on coast live oak (Quercus agrifolia) and bay laurel (Umbellularia californica), dominant hosts that comprised 39.7 and 46.2% of the individuals at the study site, respectively. All tests for inoculum production from the surface of infected coast live oak bark or exudates from cankers were negative. In contrast, sporangia and chlamydospores were produced on the surface of infected bay laurel leaves. Mean number of zoospores produced from infected bay laurel leaves under natural field conditions during rainstorms was 1,173.0 ± SE 301.48, and ranged as high as 5,200 spores/leaf. P. ramorum was recovered from rainwater, soil, litter, and streamwater during the mid- to late rainy season in all 3 years of the study. P. ramorum was not recovered from sporadic summer rains or soil and litter during the hot, dry summer months. Concentrations of inoculum in rainwater varied significantly from year to year and increased as the rainy season progressed for the two complete seasons that were studied. Potential dispersal distances were investigated for rainwater, soil, and streamwater. In rainwater, inoculum moved 5 and 10 m from the inoculum source. For soil, transmission of inoculum was demonstrated from infested soil to bay laurel green leaf litter, and from bay laurel green leaf litter to aerial leaves of bay laurel seedlings. One-third to one-half of the hikers tested at the study site during the rainy season also were carrying infested soil on their shoes. In streamwater, P. ramorum was recovered from an unforested site in pasture ≈ 1 km downstream of forest with inoculum sources. In total, these studies provide details on the production and spread of P. ramorum inoculum in mixed-evergreen forest to aid forecasting and managing disease transmission of this environmentally destructive pathogen.

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Animal generation of green leaf litter in an arid shrubland enhances decomposition by altering litter quality and location

Journal of Arid Environments ◽

10.1016/j.jaridenv.2017.11.003 ◽

2018 ◽

Vol 151 ◽

pp. 15-22 ◽

Cited By ~ 3

Author(s):

Jane G. Smith ◽

Heather L. Throop

Keyword(s):

Leaf Litter ◽

Litter Quality ◽

Green Leaf

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Effects of elevated carbon dioxide on green leaf tissue and leaf litter quality in an intact Mojave Desert ecosystem

Global Change Biology ◽

10.1046/j.1365-2486.2003.00608.x ◽

2003 ◽

Vol 9 (5) ◽

pp. 729-735 ◽

Cited By ~ 37

Author(s):

SHARON A. BILLINGS ◽

STEPHEN F. ZITZER ◽

HEATHER WEATHERLY ◽

SEAN M. SCHAEFFER ◽

T. CHARLET ◽

...

Keyword(s):

Carbon Dioxide ◽

Leaf Litter ◽

Mojave Desert ◽

Litter Quality ◽

Leaf Tissue ◽

Elevated Carbon Dioxide ◽

Desert Ecosystem ◽

Green Leaf

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Oncogenesis and the Lucké Virus

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100100743 ◽

1968 ◽

Vol 26 ◽

pp. 200-201

Author(s):

A. E. Vatter ◽

J. Zambernard

Keyword(s):

Rna Viruses ◽

Vegetative State ◽

Temperature Sensitive ◽

Structural Level ◽

Oncogenic Viruses ◽

Dna Viruses ◽

Leopard Frogs ◽

Renal Adenocarcinoma ◽

Induced Tumors ◽

Northern Leopard Frogs

Oncogenic viruses, like viruses in general, can be divided into two classes, those that contain deoxyribonucleic acid (DNA) and those that contain ribonucleic acid (RNA). The RNA viruses have been recovered readily from the tumors which they cause whereas, the DNA-virus induced tumors have not yielded the virus. Since DNA viruses cannot be recovered, the bulk of present day investigations have been concerned with RNA viruses.The Lucké renal adenocarcinoma is a spontaneous tumor which occurs in northern leopard frogs (Rana pipiens) and has received increased attention in recent years because of its probable viral etiology. This hypothesis was first advanced by Lucké after he observed intranuclear inclusions in some of the tumor cells. Tumors with inclusions were examined at the fine structural level by Fawcett who showed that they contained immature and mature virus˗like particles.The use of this system in the study of oncogenic tumors offers several unique features, the virus has been shown to contain DNA and it can be recovered from the tumor, also, it is temperature sensitive. This latter feature is of importance because the virus can be transformed from a latent to a vegetative state by lowering or elevating the environmental temperature.

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Plant Pathology Diagnosed by X-Ray Microanalysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100129152 ◽

1987 ◽

Vol 45 ◽

pp. 974-975

Author(s):

J. H. Resau ◽

N. Howell ◽

S. H. Chang

Keyword(s):

Electron Microscopy ◽

Plant Pathology ◽

Biochemical Characterization ◽

Nutrient Deficiency ◽

Green Leaf ◽

Parasitic Infestation ◽

X Ray

Spinach grown in Texas developed “yellow spotting” on the peripheral portions of the leaves. The exact cause of the discoloration could not be determined as there was no evidence of viral or parasitic infestation of the plants and biochemical characterization of the plants did not indicate any significant differences between the yellow and green leaf portions of the spinach. The present study was undertaken using electron microscopy (EM) to determine if a micro-nutrient deficiency was the cause for the discoloration.Green leaf spinach was collected from the field and sent by express mail to the EM laboratory. The yellow and equivalent green portions of the leaves were isolated and dried in a Denton evaporator at 10-5 Torr for 24 hrs. The leaf specimens were then examined using a JEOL 100 CX analytical microscope. TEM specimens were prepared according to the methods of Trump et al.

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