Translocation of 14C in ponderosa pine seedlings

1971 ◽  
Vol 49 (1) ◽  
pp. 167-171 ◽  
Author(s):  
Robert R. Ziemer

The movement of 14C from the old needles to the roots, and later to the new needles, was measured in 2-year-old ponderosa pine seedlings. The seedlings were in one of three growth stages at the time of the feeding of 14CO2: 9 days before spring bud break with no root activity; 7 days before spring bud break with high root activity; and 7 days after spring bud break with moderate root activity. The form of the curves of count rate plotted against time are similar for a given plant part. Immediately after being fed 14CO2, year-old needles had high 14C count rates which dropped rapidly, leveled out within 7 to 10 days, and reached a steady state residual count rate after 10 to 20 days. The decrease in count rate from the old needles was followed by an increase in count rate by the root tip and (or) the new needles. The count rate of the root tips increased from background to a peak within 3 to 7 days, then decreased for the duration of the study. The details and timing of movement of 14C to and from plant parts was a function of the growth state at the time of 14CO2 feeding.

2010 ◽  
Vol 40 (10) ◽  
pp. 1940-1950 ◽  
Author(s):  
C. Barroetaveña ◽  
M. B. Pildain ◽  
M. E. Salgado Salomón ◽  
J. L. Eberhart

Ponderosa pine ( Pinus ponderosa Dougl. ex P. & C. Laws.), an ectomycorrhiza (EM) dependent species, has been widely introduced in Patagonia, Argentina. This study used morphotyping, restriction analysis, and sequencing of EM root tips from ponderosa pine seedlings in two nurseries to assess the complete EM fungus (EMF) richness, to confirm doubtful identities of commonly reported morphotypes, and to evaluate the efficiency of morphotyping compared with molecular analysis. This interdisciplinary approach together with the fact that is the first study in which Patagonian nurseries EMF are genetically evaluated contributes to the general knowledge of this important group of fungi. Sequencing revealed the presence of 11 taxa. Basidiomycetes included Thelephoraceae ( Tomentella sp.), Atheliaceae ( Amphinema byssoides (Pers.) J. Erikss.), Hydnangiaceae ( Laccaria sp.), Rhizopogonaceae ( Rhizopogon roseolus (Corda) Th. Fr.), and Cortinariaceae ( Hebeloma mesophaeum (Pers.) Quel.). Ascomycetes included Pezizaceae ( Wilcoxina mikolae (Chin S. Yang & H.E. Wilcox) Chin S. Yang & Korf and Wilcoxina sp.) and Tuberaceae ( Tuber sp.). Morphotyping proved to be useful for certain EMF species (R. roseolus, H. mesophaeum, A. byssoides, and to a lesser extent Tuber sp.) in which some morphological features are conspicuous and unique. Our detection of W. mikolae and Wilcoxina sp. are new records for ponderosa pine in Patagonia. All of the EM taxa identified are common to pine plantations and nurseries around the world, and no indigenous EM associated with native Nothofagus spp. were found.


1994 ◽  
Vol 24 (8) ◽  
pp. 1531-1538 ◽  
Author(s):  
William FJ. Parsons ◽  
Steven L. Miller ◽  
Dennis H. Knight

Belowground responses to aboveground disturbance were studied in experimental gaps created in a 95-year-old Pinuscontorta ssp. latifolia (Engelm. ex Wats.) Critchfield stand, southeastern Wyoming. We hypothesized that active fine root densities within the canopy gaps would remain comparable with densities in undisturbed forest and would not decline abruptly until a threshold number of trees had been killed, after which the root gap would be recolonized gradually and centripetally. One-, 5-, 15-, and 30-tree clusters were felled to create a series of gaps in the root mat of lodgepole pine forest soil. For 2 years, densities of ectomycorrhizal (ECM) root tips were determined by intensive soil coring in the experimental gaps and in a nearby 8-year-old clearcut. Data on fine-root activity were obtained using mesh screens inserted into the soil and incubated for up to 5 years. The results were consistent with the original hypothesis, but no clear threshold gap size was observed for ECM root tips. Densities of active ECM root tips measured along transects through one of the 30-tree gaps decreased quickly within 5–6 m of the forest edge, and did not significantly differ from zero at the center of the gap; in contrast to the 2-year-old gap, active ECM densities were fairly constant across the 8-year-old clearcut. Moreover, root-tip densities declined gradually with increasing gap size, while fine root penetrations of the mesh screens were significantly lower in the 30-tree gaps than in the smaller gaps. During the first 3 years, fine roots intercepting the screens were nonmycorrhizal; at the final removal, root screens that had been incubated for 1837 days in the gaps, including the 30-tree gaps, contained ectomycorrhizal root tips. The root screen removal data suggested that belowground gaps persisted 5 years after initial clear-felling of the 30-tree clusters, but the screens also provided evidence for closure from the edges of these gaps.


2017 ◽  
Vol 10 (1) ◽  
pp. 35-45
Author(s):  
N.F. Lunkova ◽  
N.A. Burmistrova ◽  
M.S. Krasavina

Background:A growing part of the root is one of the most active sinks for sucrose coming from source leaves through the phloem. In the root, sucrose is unloaded from conducting bundles and is distributed among the surrounding cells. To be involved in the metabolism, sucrose should disintegrate into hexoses by means of degrading enzymes.Aims:The aim of this research was to explore the possibility of the involvement of one such enzymes, invertase, in phloem unloading as well as distribution of its activity in the functionally different tissues of the plant root tips.Method:To estimate the enzyme activities in root tissues, we applied two techniques: the histochemical method using nitro blue tetrazolium. The localization of phloem unloading was studied with carboxyfluorescein, a fluorescent marker for symplastic transport.Results:Invertase activity was not detected in the apical part of the meristem. It appeared only between the basal part of this zone and the beginning of the elongation zone. There is the root phloem unloading in that area. Invertase activity increased with increasing the distance from the root tip and reached the highest values in the region of cell transition to elongation and in the elongation zone. The activities of the enzyme varied in different tissues of the same zone and sometimes in the neighboring cells of the same tissue. Biochemical determination of invertase activity was made in the maize root segments coincident to the zones of meristem, cell elongation and differentiation. The results of both methods of determination of invertase activity were in agreement.Conclusion:It was concluded that phloem unloading correlated with invertase activity, possibly because of the activation of invertase by unloaded sucrose. Invertase is one of the factors involved in the processes preparing the cells for their transition to elongation because the concentration of osmotically active hexoses increases after cleavage of sucrose, that stimulates water entry into the cells, which is necessary for elongation growth.


1999 ◽  
Vol 14 (3) ◽  
pp. 164-168 ◽  
Author(s):  
Michael J. Pipas ◽  
Gary W. Witmer

Abstract A 2 yr study on the Rogue River and Mt. Hood National Forests in Oregon evaluated physical barriers for protection of Pinus ponderosa seedlings against damage by Thomomys talpoides. Seedlings protected with one of three weights of: (1) plastic mesh tubing (Vexar®) or (2) sandpapertubing (Durite®) were evaluated against control seedlings. On the Rogue River sites, Vexar® seedlings had the highest survival (62.6%), followed by the controls (59.1%), then Durite® seedlings (17.9%). Gophers were the primary cause of death for the Vexar® seedlings, versus desiccation for the Durite® seedlings. On the Mt. Hood sites, heavyweight Vexar® seedlings had the highest survival (35.4%), medium-weight Durite® seedlings the lowest (2.7%). Seedling mortality caused by gophers was highest for controls (70.2%), followed by light-weight (62.2%) and heavy-weight (53.9%) Vexar® treatments. Overall survival was low (Rogue River = 42%, Mt. Hood = 19.8%). Growth was greatest for the control seedlings but only significantly greater than growth of Durite® seedlings on the Rogue River sites. Growth of seedlings was not compromised by the Vexar® tubing. Although neither type of tubing was highly protective, Vexar® tubes performed better than Durite® tubes. West. J. Appl. For. 14(3):164-168.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tina Unuk Nahberger ◽  
Gian Maria Niccolò Benucci ◽  
Hojka Kraigher ◽  
Tine Grebenc

AbstractSpecies of the genus Tuber have gained a lot of attention in recent decades due to their aromatic hypogenous fruitbodies, which can bring high prices on the market. The tendency in truffle production is to infect oak, hazel, beech, etc. in greenhouse conditions. We aimed to show whether silver fir (Abies alba Mill.) can be an appropriate host partner for commercial mycorrhization with truffles, and how earthworms in the inoculation substrate would affect the mycorrhization dynamics. Silver fir seedlings inoculated with Tuber. aestivum were analyzed for root system parameters and mycorrhization, how earthworms affect the bare root system, and if mycorrhization parameters change when earthworms are added to the inoculation substrate. Seedlings were analyzed 6 and 12 months after spore inoculation. Mycorrhization with or without earthworms revealed contrasting effects on fine root biomass and morphology of silver fir seedlings. Only a few of the assessed fine root parameters showed statistically significant response, namely higher fine root biomass and fine root tip density in inoculated seedlings without earthworms 6 months after inoculation, lower fine root tip density when earthworms were added, the specific root tip density increased in inoculated seedlings without earthworms 12 months after inoculation, and general negative effect of earthworm on branching density. Silver fir was confirmed as a suitable host partner for commercial mycorrhization with truffles, with 6% and 35% mycorrhization 6 months after inoculation and between 36% and 55% mycorrhization 12 months after inoculation. The effect of earthworms on mycorrhization of silver fir with Tuber aestivum was positive only after 6 months of mycorrhization, while this effect disappeared and turned insignificantly negative after 12 months due to the secondary effect of grazing on ectomycorrhizal root tips.


1986 ◽  
Vol 16 (4) ◽  
pp. 696-700 ◽  
Author(s):  
Chris P. Andersen ◽  
Edward I. Sucoff ◽  
Robert K. Dixon

The influence of root zone temperature on root initiation, root elongation, and soluble sugars in roots and shoots was investigated in a glasshouse using 2-0 red pine (Pinusresinosa Ait.) seedlings lifted from a northern Minnesota nursery. Seedlings were potted in a sandy loam soil and grown in chambers where root systems were maintained at 8, 12, 16, or 20 °C for 27 days; seedling shoots were exposed to ambient glasshouse conditions. Total new root length was positively correlated with soil temperature 14, 20, and 27 days after planting, with significantly more new root growth at 20 °C than at other temperatures. The greatest number of new roots occurred at 16 °C; the least, at 8 °C. Total soluble sugar concentrations in stem tissue decreased slightly as root temperature increased. Sugar concentrations in roots were similar at all temperatures. The results suggest that root elongation is suppressed more than root tip formation when red pine seedlings are exposed to the cool soil temperatures typically found during spring and fall outplanting.


2003 ◽  
Vol 69 (1) ◽  
pp. 327-333 ◽  
Author(s):  
Renske Landeweert ◽  
Paula Leeflang ◽  
Thom W. Kuyper ◽  
Ellis Hoffland ◽  
Anna Rosling ◽  
...  

ABSTRACT Molecular identification techniques based on total DNA extraction provide a unique tool for identification of mycelium in soil. Using molecular identification techniques, the ectomycorrhizal (EM) fungal community under coniferous vegetation was analyzed. Soil samples were taken at different depths from four horizons of a podzol profile. A basidiomycete-specific primer pair (ITS1F-ITS4B) was used to amplify fungal internal transcribed spacer (ITS) sequences from total DNA extracts of the soil horizons. Amplified basidiomycete DNA was cloned and sequenced, and a selection of the obtained clones was analyzed phylogenetically. Based on sequence similarity, the fungal clone sequences were sorted into 25 different fungal groups, or operational taxonomic units (OTUs). Out of 25 basidiomycete OTUs, 7 OTUs showed high nucleotide homology (≥99%) with known EM fungal sequences and 16 were found exclusively in the mineral soil. The taxonomic positions of six OTUs remained unclear. OTU sequences were compared to sequences from morphotyped EM root tips collected from the same sites. Of the 25 OTUs, 10 OTUs had ≥98% sequence similarity with these EM root tip sequences. The present study demonstrates the use of molecular techniques to identify EM hyphae in various soil types. This approach differs from the conventional method of EM root tip identification and provides a novel approach to examine EM fungal communities in soil.


2014 ◽  
Vol 21 (12) ◽  
pp. 1308-1319
Author(s):  
Setsuko Komatsu ◽  
Myeong W. Oh ◽  
Hee Y. Jang ◽  
Soo J. Kwon ◽  
Hye R. Kim ◽  
...  

Plant root systems form complex networks with the surrounding soil environment and are controlled by both internal and external factors. To better understand the function of root tips of soybean during germination, three proteomic techniques were used to analyze the protein profiles of root tip cells. Proteins were extracted from the root tips of 4-dayold soybean seedlings and analyzed using two-dimensional (2D) gel electrophoresis-based proteomics, SDS-gel based proteomics, and gel-free proteomics techniques. A total of 121, 862, and 341 proteins were identified in root tips using the 2D gel-based, SDS gel-based, and gel-free proteomic techniques, respectively. The proteins identified by 2D gel-based proteomic analysis were predominantly localized in the cytoplasm, whereas nuclear-localized proteins were most commonly identified by the SDS gel-based and gel-free proteomics techniques. Of the 862 proteins identified in the SDS gelbased proteomic analysis, 190 were protein synthesis-related proteins. Furthermore, 24 proteins identified using the 2Dgel based proteomic technique shifted between acidic and basic isoelectric points, and 2 proteins, heat shock protein 70.2 and AAA-type ATPase, displayed two different molecular weights at the same isoelectric point. Taken together, these results suggest that a number of proteins related to protein synthesis and modification are activated in the root tips of soybean seedlings during germination.


Weed Science ◽  
1982 ◽  
Vol 30 (1) ◽  
pp. 98-101 ◽  
Author(s):  
John C. Tappeiner ◽  
Steven R. Radosevich

An experiment was established in 1961 to determine the influence of bearmat (Chamaebatia foliolosa Benth.) competition on ponderosa pine (Pinus ponderosa Laws.) survival and growth. Ponderosa pine seedlings were planted in bearmat which was: (A) untreated, (B) sprayed with a mixture of 2,4-D [(2,4-dichlorophenoxy)acetic acid] and 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid], and (C) eliminated by a combination of herbicide, clipping sprouts, and trenching to prevent root and rhizome invasion. Ponderosa pine survival after 19 yr averaged 9%, 66%, and 90%, respectively, for the three treatments. Tree height after 19 yr averaged 1.6, 1.9, and 5.7 m for treatments A, B, and C, respectively. Soil moisture use was initially less on the herbicide-treated than on the untreated plots, but bearmat quickly sprouted after application to compete with the pine seedlings for moisture. After 19 yr the bearmat was more dense and appeared to be more vigorous on the sprayed plots than on those receiving no treatment. We estimate that 75% reduction in net wood production could result after 50 yr on this site from bearmat competition.


Sign in / Sign up

Export Citation Format

Share Document