scholarly journals Responses of the Fine Roots of Citrus to Dry Surface Soil

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 577a-577
Author(s):  
David M. Eissenstat ◽  
Javier F. Espeleta ◽  
Eric L. Whaley
Keyword(s):  
Fine Roots ◽  
Surface Soil ◽  
Fine Root ◽  
Phosphate Uptake ◽  
Physiological Activity ◽  
Soil Layer ◽  
Phosphorus Uptake ◽  
Mature Tree ◽  
Dry Soil ◽  
Split Pot

Despite the frequent occurrence of hot, dry surface soil, little is known about the fate of roots in this soil layer during and following periods of surface drought. Phosphorus uptake kinetics were examined in surface roots of citrus seedlings exposed to different periods of drought. Exposure to dry soil for up to 43 days had no effect on phosphate uptake of excised roots measured at solution concentrations of 50, 750, and 1500 μm phosphate. Effects of surface drought on fine root behavior of seedlings and bearing trees were examined in the field using a split-pot arrangement. At the end of 5 weeks of drought, only about 1% of the roots in the top pot of either the seedling or tree had died. By 8 to 9 weeks of drought, about 26% of the fine laterals of the adult citrus had died, but only 6% had died in the seedling. After 15 weeks of drought, 33% of the mature tree fine roots had died but only 8% had died in the seedling. Root-soil respiration per gram root at this time was at least twice as high in the seedling as in the mature tree. Fine roots of citrus are remarkably tolerant to dry surface soils of about 5 weeks duration, both in terms of root survival and resumption of physiological activity after rewetting.

scholarly journals Effect of disturbance on fine root biomass in the Tropical moist forest of eastern Nepal

2013 ◽  
Vol 2 ◽  
pp. 10-16 ◽  
Author(s):  
Tilak Prasad Gautam ◽  
Tej Narayan Mandal
Keyword(s):  
Fine Roots ◽  
Root Biomass ◽  
Surface Soil ◽  
Fine Root ◽  
Soil Layer ◽  
Fine Root Biomass ◽  
Nitrogen Stock ◽  
Moist Forest ◽  
Surface Soil Layer ◽  
Disturbed Stand

Fine root biomass (<5 mm diameter) was estimated in 0-15 cm and 15- 30 cm soil depths of disturbed and undisturbed stands of tropical moist forest in eastern Nepal. The value of root mass was higher (4.28 t ha-1) in the undisturbed stand than the disturbed stand (2.04 t ha-1). The biomass of smaller fine roots (<2 mm diameter) was 1.51 and 3.2 t ha-1 in the disturbed and undisturbed stands respectively. Most of the fine roots were present in the surface soil layer (0-15 cm), in both the disturbed and undisturbed stands (67% in the disturbed and 64% in the undisturbed). The nitrogen stock in the fine roots was more (38.61 kg ha-1) in undisturbed stand than the disturbed stand (16.93 kg ha-1). More nitrogen was confined in the fine roots of <2 mm diameter in both undisturbed (28.8 kg ha-1) and disturbed (13.59 kg ha-1) stands. DOI: http://dx.doi.org/10.3126/njbs.v2i0.7484 Nepalese Journal of Biosciences 2 : 10-16 (2012)

scholarly journals Biochar induced improvement in root system architecture enhances nutrient assimilation by cotton plant seedlings

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lei Feng ◽  
Wanli Xu ◽  
Guangmu Tang ◽  
Meiying Gu ◽  
Zengchao Geng
Keyword(s):  
Root System ◽  
System Architecture ◽  
Fine Roots ◽  
Nitrogen Assimilation ◽  
Surface Soil ◽  
Soil Layer ◽  
Root System Architecture ◽  
Seedling Stage ◽  
Agronomic Efficiency ◽  
Surface Soil Layer

Abstract Background Raising nitrogen use efficiency of crops by improving root system architecture is highly essential not only to reduce costs of agricultural production but also to mitigate climate change. The physiological mechanisms of how biochar affects nitrogen assimilation by crop seedlings have not been well elucidated. Results Here, we report changes in root system architecture, activities of the key enzymes involved in nitrogen assimilation, and cytokinin (CTK) at the seedling stage of cotton with reduced urea usage and biochar application at different soil layers (0–10 cm and 10–20 cm). Active root absorption area, fresh weight, and nitrogen agronomic efficiency increased significantly when urea usage was reduced by 25% and biochar was applied in the surface soil layer. Glutamine oxoglutarate amino transferase (GOGAT) activity was closely related to the application depth of urea/biochar, and it increased when urea/biochar was applied in the 0–10 cm layer. Glutamic-pyruvic transaminase activity (GPT) increased significantly as well. Nitrate reductase (NR) activity was stimulated by CTK in the very fine roots but inhibited in the fine roots. In addition, AMT1;1, gdh3, and gdh2 were significantly up-regulated in the very fine roots when urea usage was reduced by 25% and biochar was applied. Conclusion Nitrogen assimilation efficiency was significantly affected when urea usage was reduced by 25% and biochar was applied in the surface soil layer at the seedling stage of cotton. The co-expression of gdh3 and gdh2 in the fine roots increased nitrogen agronomic efficiency. The synergistic expression of the ammonium transporter gene and gdh3 suggests that biochar may be beneficial to amino acid metabolism.

scholarly journals Biochar effect - mediated ammonium transporter genes and GDH may be the core of improvement nitrogen assimilation in cotton seedling

2020 ◽  
Author(s):  
Lei Feng ◽  
Guangmu Tang ◽  
Wanli Xu ◽  
Meiying Gu ◽  
Zengchao Geng
Keyword(s):  
Seedling Growth ◽  
Fine Roots ◽  
Nitrogen Assimilation ◽  
Surface Soil ◽  
Soil Layer ◽  
Assimilation Efficiency ◽  
Seedling Stage ◽  
Nitrogen Efficiency ◽  
Ammonium Transporter ◽  
Cotton Seedling

AbstractBiochar enhancement of nitrogen efficiency in crops is highly essential not only to reduce costs of agricultural production but also to conserve resources, lower energy consumption for products of these fertilizers, strengthen soil health, and eventually helps in slowing climate change; however nitrogen efficiency physiology by biochar effects is not clear. Here, we reported on the morphological, nitrogen metabolism and cytokinin, at seedling stage, under different layers of biochar and limited urea conditions grown in soil culture. Expression profile of miRNAs and AOB was further studied in fine and medium roots. It showed active root absorption area, fresh weight, and nitrogen agronomic efficiency responded significantly under biochar and reduction by 20% urea condition in the surface soil layer. Also, NR and GPT activity in fine roots remarkably increased with cytokinin, but decreased significantly in medium roots, meanwhile both NR and GDH activity did so. GOGAT activity was to be dependent with biochar and urea locations. In addition, AMT1;1, gdh3 and gdh2 in fine roots showed their up-regulation with reduction 20% urea and biochar. It revealed that co-expression of gdh3 and gdh2 in fine roots significantly affected nitrogen assimilation under reduction 20% urea with biochar on surface soil at seedling stage.HighlightsThe co-expression of ammonium transporter gene and GDH induced by biochar effect improves nitrogen efficiency and seedling growth.These data emphasizes the importance of effects of cytokinin on nitrate reductase activity closely related to the position under biochar condition, which is a key element of enhancement nitrogen assimilation efficiency in cotton seedling.Biochar addition applied into 0 to 10cm soil had a more positive effect on seedling growth than that into 10 to 20cm soil layers.

Coupling effect of water and nitrogen on the morphology and distribution of fine root in surface soil layer of youngPopulus×euramericanaplantation

2015 ◽  
Vol 35 (11) ◽  
Author(s):  
闫小莉 YAN Xiaoli ◽  
戴腾飞 DAI Tengfei ◽  
邢长山 XING Changshan ◽  
贾黎明 JIA Liming ◽  
张龙宁 ZHANG Longning
Keyword(s):  
Surface Soil ◽  
Fine Root ◽  
Coupling Effect ◽  
Soil Layer ◽  
Effect Of Water ◽  
Surface Soil Layer

scholarly journals Root biomass of Fagus sylvatica L. stands depending on the climatic conditions

2016 ◽  
Vol 58 (4) ◽  
pp. 220-227 ◽  
Author(s):  
Dorota Grygoruk
Keyword(s):  
Fagus Sylvatica ◽  
Fine Roots ◽  
Root Biomass ◽  
Fine Root ◽  
Soil Layer ◽  
Fine Root Biomass ◽  
Climatic Conditions ◽  
Forest Trees ◽  
Soil Layers ◽  
Fagus Sylvatica L

Abstract Fine root biomass of forest trees is a recognised indicator of environmental changes in the conditions of global climate change. The present study was carried out in six old-growth beech forests (112-140 years) located in different climatic conditions on the range border of Fagus sylvatica L. in Poland. The root biomass was investigated by soil coring method in the upper soil layers (0-5 cm, 5-15 cm and total layer 0-15 cm). The significantly greater total root biomass was found in the beech stands, which characterised by higher average precipitation and lower average annual temperatures in the period 2000-2005. The share of roots of diameter > 5 mm increased with increasing depth of top soils. Biomass of fine roots (diameter ≤ 2 mm) decreased with increasing depth of upper soil layers. The average biomass of fine roots ranged from 175.36 to 418.16 g m-2 in the soil layer 0-15 cm. The significant differences of fine root biomass were found between studied stands in the soil layers 0-5 cm and 0-15 cm. Also, it was found significant positive correlation between fine root biomass in the soil layer 0-15 cm and precipitation during the growing season in 2006. Precipitation in the study period was connected with very high rainfall in August 2006, repeatedly exceeding the long-term monthly levels. Regional climatic conditions, in that extreme weather events in growing seasons can significantly to affect changes of fine root biomass of forest trees, consequently, changes of relationships between the growth of above- and below-ground of the old-growth forest stands.

scholarly journals Ca/Al ratio in Norway spruce fine roots on monitoring plots in the Czech Republic

2014 ◽  
Vol 60 (No. 3) ◽  
pp. 121-131 ◽  
Author(s):  
V. Šrámek ◽  
V. Fadrhonsová ◽  
L. Jurkovská
Keyword(s):  
Czech Republic ◽  
Norway Spruce ◽  
Fine Roots ◽  
Fine Root ◽  
Soil Layer ◽  
Forest Health ◽  
Aluminium Toxicity ◽  
Molar Ratio ◽  
Crown Condition ◽  
The Czech Republic

This article is focused on the evaluation of the Al/Ca ratio in fine roots of Norway spruce on the plots belonging to the ICP Forests monitoring programme in the Czech Republic. In total 122 fine root samples were collected from twenty plots from two soil layers of 0&ndash;10 and 10&ndash;20 cm and then analysed. The mean Ca/Al molar ratio in the fine roots from the 0&ndash;10 cm topsoil layer is higher than in the lower 10&ndash;20 cm soil layer, which corresponds to the distribution of fine roots &ndash; on average 80% of fine roots were found in the topsoil. 6% of the samples in the lower soil layer strongly indicate aluminium stress (Ca/Al &lt; 0.1) and 30% of the samples may demonstrate the adverse effects of aluminium (&lt; 0.2). On the other hand, no relationship was found between the Ca/Al ratio in the fine roots and the fine root biomass and vitality or crown condition. These results suggest that the potential aluminium toxicity is not the driving factor of the crown condition in Norway spruce and the Ca/Al ratio itself does not pose a risk to forest health in the region. &nbsp;

Influence of Pruning and Irrigation on Root Longevity of `Concord' Vines

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 511a-511
Author(s):  
L.H. Comas ◽  
D.M. Eissenstat ◽  
A.N. Lakso ◽  
R. Dunst
Keyword(s):  
Fine Roots ◽  
Fine Root ◽  
Cultural Practices ◽  
Growing Season ◽  
Root Production ◽  
Root Dynamics ◽  
Supplemental Irrigation ◽  
Root Longevity ◽  
Root Lifespan ◽  
Median Lifespan

Improved cultural practices in grape require a better understanding of root growth and physiology. Seasonal root dynamics were examined in mature `Concord' vines with balanced or minimal-pruning, and with or without supplemental irrigation in Fredonia, N.Y. Fine roots were continuously produced during the growing season starting in mid-June around time of bloom. Roots began to die in September at verasion. Minimal-pruned vines produced more roots than balanced-pruned vines, with the minimal-pruned/unirrigated vines producing the most roots. Irrigation and pruning delayed fine root production at the beginning of the growing season. Peak fine root flush was 16 June to 21 July 1997 for the minimal-pruned/unirrigated treatment, while peak flush was 7 July to 2 Sept. 1997 for balanced-pruned/irrigated treatment. In minimal-pruned vines, many roots were observed down to depths of 120 cm. In contrast, balanced-pruned vines had very few fine roots deeper than 40 cm. From initial observations, median lifespan of fine roots was 5 to 9.5 weeks, depending on treatment and depth in soil. Fine roots lived longer in the top 15-cm than in the 16- to 30-cm layer of soil in all treatments. Both minimal pruning and irrigation increased root lifespan. Fine roots had the shortest lifespan in the balanced-pruned/unirrigated treatment and the longest lifespan in the minimal-pruned/irrigated treatment.

Outflows of Organic Halide Precursors from Forest Regions

1989 ◽  
Vol 21 (12) ◽  
pp. 1877-1880 ◽  
Author(s):  
S. Saito ◽  
K. Hattori ◽  
T. Okumura
Keyword(s):  
Water Quality ◽  
River Basin ◽  
Surface Soil ◽  
Soil Layer ◽  
Water Quality Monitoring ◽  
Quality Monitoring ◽  
Deep Soil ◽  
Organic Halide ◽  
Forest Regions ◽  
Surface Soil Layer

Outflows of organic halide precursors (OXPs) from forest regions were studied in relation to water quality monitoring in the Yodo River basin. Firstly, the contribution of outflows from forest regions relative to the total was roughly estimated. Then equations for flows of these substances were formulated, divided into four different subflow categories: precipitation; throughfall; surface soil layer; and, deep soil layer. Finally, annual outflow loads were calculated for a test forest area.

scholarly journals Organic mulching promotes soil organic carbon accumulation to deep soil layer in an urban plantation forest

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiaodan Sun ◽  
Gang Wang ◽  
Qingxu Ma ◽  
Jiahui Liao ◽  
Dong Wang ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Content ◽  
Fine Roots ◽  
Soil Layer ◽  
Carbon Accumulation ◽  
Bulk Soil ◽  
Organic Mulch ◽  
The Impact ◽  
Soc Fractions

Abstract Background Soil organic carbon (SOC) is important for soil quality and fertility in forest ecosystems. Labile SOC fractions are sensitive to environmental changes, which reflect the impact of short-term internal and external management measures on the soil carbon pool. Organic mulching (OM) alters the soil environment and promotes plant growth. However, little is known about the responses of SOC fractions in rhizosphere or bulk soil to OM in urban forests and its correlation with carbon composition in plants. Methods A one-year field experiment with four treatments (OM at 0, 5, 10, and 20 cm thicknesses) was conducted in a 15-year-old Ligustrum lucidum plantation. Changes in the SOC fractions in the rhizosphere and bulk soil; the carbon content in the plant fine roots, leaves, and organic mulch; and several soil physicochemical properties were measured. The relationships between SOC fractions and the measured variables were analysed. Results The OM treatments had no significant effect on the SOC fractions, except for the dissolved organic carbon (DOC). OM promoted the movement of SOC to deeper soil because of the increased carbon content in fine roots of subsoil. There were significant correlations between DOC and microbial biomass carbon and SOC and easily oxidised organic carbon. The OM had a greater effect on organic carbon fractions in the bulk soil than in the rhizosphere. The thinnest (5 cm) mulching layers showed the most rapid carbon decomposition over time. The time after OM had the greatest effect on the SOC fractions, followed by soil layer. Conclusions The frequent addition of small amounts of organic mulch increased SOC accumulation in the present study. OM is a potential management model to enhance soil organic matter storage for maintaining urban forest productivity.

scholarly journals Observations on early fungal infections with relevance for replant disease in fine roots of the rose rootstock Rosa corymbifera 'Laxa'

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
G. Grunewaldt-Stöcker ◽  
C. Popp ◽  
A. Baumann ◽  
S. Fricke ◽  
M. Menssen ◽  
...  
Keyword(s):  
Fine Roots ◽  
Woody Plant ◽  
Fine Root ◽  
Fungal Infections ◽  
Thin Sections ◽  
Replant Disease ◽  
Pot Trials ◽  
Worldwide Phenomenon ◽  
First Time ◽  
The Rose

AbstractReplant disease is a worldwide phenomenon affecting various woody plant genera and species, especially within the Rosaceae. Compared to decades of intensive studies regarding replant disease of apple (ARD), the replant disease of roses (RRD) has hardly been investigated. The etiology of RRD is also still unclear and a remedy desperately needed. In greenhouse pot trials with seedlings of the RRD-sensitive rootstock Rosa corymbifera ‘Laxa’ cultured in replant disease affected soils from two different locations, early RRD symptom development was studied in fine roots. In microscopic analyses we found similarities to ARD symptoms with regards to structural damages, impairment in the root hair status, and necroses and blackening in the cortex tissue. Examinations of both whole mounts and thin sections of fine root segments revealed frequent conspicuous fungal infections in association with the cellular disorders. Particularly striking were fungal intracellular structures with pathogenic characteristics that are described for the first time. Isolated fungi from these tissue areas were identified by means of ITS primers, and many of them were members of the Nectriaceae. In a next step, 35 of these isolates were subjected to a multi-locus sequence analysis and the results revealed that several genera and species were involved in the development of RRD within a single rose plant. Inoculations with selected single isolates (Rugonectria rugulosa and Ilyonectria robusta) in a Perlite assay confirmed their pathogenic relationship to early necrotic host plant reactions, and symptoms were similar to those exhibited in ARD.

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