Distribution and density of the root system of macadamia on krasnozem soil and some effects of legume groundcovers on fibrous root density

2003 ◽  
Vol 43 (5) ◽  
pp. 503 ◽  
Author(s):  
D. J. Firth ◽  
R. D. B. Whalley ◽  
G. G. Johns
Keyword(s):  
Root System ◽  
Root Length ◽  
Root Length Density ◽  
Root Systems ◽  
Soil Cores ◽  
Fibrous Root ◽  
Proteoid Roots ◽  
Dry Conditions ◽  
Proteoid Root ◽  
Fibrous Roots

Whole-tree excavations, root-core and minirhizotron studies indicate that the grafted macadamia tree root system is relatively shallow and spreading, with a short taproot and most of the fibrous root system near the soil surface, while ungrafted trees have a longer taproot. The length of fibrous roots diminished with depth and distance from the trunk. This pattern is consistent with other fruit trees, in that the highest density is generally within 1 m of the trunk. Values obtained in core samples in this study were 4.97 (± 0.43) cm/cm3 and 1.67 (± 0.45) cm/cm3 for 0–10 cm and 10–20 cm at 0.5 m from the trunk, and 2.34 and 1.08 cm/cm3, respectively, at 1 m from the trunk at Clunes. These values were similar to those obtained in separate studies in 1991–93, involving assessments at 5�cm depth increments down to 15 cm, where mean root length densities were 2.0–3.5 cm/cm3 and 1.3–1.9 cm/cm3 at 0–5 cm and 5–15 cm depth, respectively, 1.4 m from the trunk. Root length under old trees in bare soil at Dorroughby and Clunes, using minirhizotrons (0.25–0.40 cm/cm2) and soil cores (1.14 and 3.50 cm/cm3, respectively), was similar to that found at other sites in the study area (minirhizotrons 0.28–0.33 cm/cm2; soil cores 1.25–2.80 cm/cm3). There is an apparent lower rate of decrease in root length density with increasing distance from the trunk at 10–20 cm compared with 0–10 cm. New root growth occurred predominantly in autumn, but some new fibrous roots were produced in early winter and spring. Proteoid roots were found in abundance in soil cores and adjacent to minirhizotron tubes and there were more of them in the root systems of younger trees at Clunes than with older trees at Dorroughby. Proteoid roots were found at a greater depth than previously recorded for other Proteaceae species, and appeared to retain their function in relatively dry conditions for more than a year. Non-proteoid fibrous roots at the minirhizotron surface appeared to be functional for about 1.5 years in relatively dry conditions, before decay after the onset of wet soil conditions.The effects of 2 newly established perennial legume groundcovers on the root systems of younger and older macadamia trees were studied over 2.5 years. In general, the presence of groundcover either had no effect on the growth of the macadamia roots or increased the root length density at some sampling dates and some depths. At Clunes, where the proteoid root length density was higher than at Dorroughby, the presence of groundcover was associated with higher proteoid root length density than that with bare ground. Arachis pintoi cv. Amarillo generally had a lower root length density than Lotus pedunculatus.

Factors affecting the distribution of proteoid roots within the root systems of two Hakea species

1973 ◽  
Vol 21 (2) ◽  
pp. 165 ◽  
Author(s):  
B Lamont
Keyword(s):  
Organic Matter ◽  
Root System ◽  
Root Systems ◽  
Physical Factors ◽  
Root Weight ◽  
Local Concentration ◽  
Horizontal Distance ◽  
Proteoid Roots ◽  
Local Soil ◽  
Proteoid Root

The proteoid roots of Hakea prostrata and H. laurina are concentrated in the surface soil horizons, even though the root systems penetrate to much greater depths. The relationships of a number of soil and plant factors to proteoid root occurrence in a given portion of the root system were examined. Pockets of humus-rich soil in any part of the root system greatly increased the proteoid root concentration in that region. The following factors, listed in their apparent order of importance, were analysed: local concentration of parent roots, local level of soil organic matter, local nitrogen availability, shoot growth, nitrogen concentration of the shoots, vertical distance of the region from the soil surface, local availability of calcium, magnesium, and potassium, local bulk density and certain other physical factors, nutrient status of the rest of the root system, horizontal distance of the region from the centre of the plant, relative maturity of parent roots in the region, and local soil pH and certain other chemical factors. The nitrogen component of soil regions high in organic matter largely accounted for their higher non-proteoid root concentration, smaller proteoid root size, greater number of laterals, and longer roots per unit weight, but not their much greater number of proteoid roots per unit total root weight. This suggests that other factors are also involved in proteoid root formation.

scholarly journals Propagation Techniques and Grafting Modify the Morphological Traits of Roots and Biomass Allocation in Avocado Trees

2016 ◽  
Vol 26 (1) ◽  
pp. 63-69 ◽  
Author(s):  
Claudia Fassio ◽  
Ricardo Cautin ◽  
Alonso Pérez-Donoso ◽  
Claudia Bonomelli ◽  
Mónica Castro
Keyword(s):  
Root System ◽  
Biomass Allocation ◽  
Root Length ◽  
Morphological Traits ◽  
Root Length Density ◽  
Root Systems ◽  
Second Order ◽  
Total Length ◽  
Shoot Ratio ◽  
Root To Shoot Ratio

Root morphological traits and biomass allocation were studied in 2-year-old ‘Duke 7’ avocado (Persea americana) trees propagated using seedling and clonal techniques. The plants either were or were not grafted with the scion ‘Hass’. Whole tree excavation 1 year after planting revealed that the propagation technique affected the root growth angle of the main roots (third order roots), the root length density (defined as the total length of roots per volume of soil), and the number of first and second order roots present. The root system of clonal trees showed a typical morphology of rooted cuttings, with a crown of roots originating from a relatively short stem, resulting in a shallow root system. Clonal trees, compared with seedlings, produced main framework roots with shallower angles and more fine roots (first and second order roots) that increased the root length density (defined as the total length of roots per volume of soil). Nongrafted seedlings exhibited a main taproot and lateral roots with narrow angles that penetrated deeper into the soil and increased the aboveground biomass but had a lower root-to-shoot ratio than nongrafted clonal trees. The grafting of both clonal and seedling trees resulted in similar root architecture and revealed that grafting significantly decreased the soil volume explored and the shoot and root biomass. Although both root systems were shallow, grafted clonal trees had a higher root-to-shoot ratio than grafted seedlings. In this study, a distinct class of roots with large diameter and unbranched growth was more abundant in the root systems of clonal trees. These types of roots (previously undescribed in avocado trees), called pioneer roots, may enhance soil exploration in clonal trees.

scholarly journals Comparison of Root System Morphology of Cucurbit Rootstocks for Use in Watermelon Grafting

2018 ◽  
Vol 28 (5) ◽  
pp. 629-636 ◽  
Author(s):  
Matthew B. Bertucci ◽  
David H. Suchoff ◽  
Katherine M. Jennings ◽  
David W. Monks ◽  
Christopher C. Gunter ◽  
...  
Keyword(s):  
Root System ◽  
Surface Area ◽  
Root Length ◽  
Dry Weight ◽  
Root Systems ◽  
Root Surface ◽  
Root Diameter ◽  
Root Surface Area ◽  
Diameter Class ◽  
Main Effect

Grafting of watermelon (Citrullus lanatus) is an established production practice that provides resistance to soilborne diseases or tolerance to abiotic stresses. Watermelon may be grafted on several cucurbit species (interspecific grafting); however, little research exists to describe root systems of these diverse rootstocks. A greenhouse study was conducted to compare root system morphology of nine commercially available cucurbit rootstocks, representing four species: pumpkin (Cucurbita maxima), squash (Cucurbita pepo), bottle gourd (Lagenaria siceraria), and an interspecific hybrid squash (C. maxima × C. moschata). Rootstocks were grafted with a triploid watermelon scion (‘Exclamation’), and root systems were compared with nongrafted (NG) and self-grafted (SG) ‘Exclamation’. Plants were harvested destructively at 1, 2, and 3 weeks after transplant (WAT), and data were collected on scion dry weight, total root length (TRL), average root diameter, root surface area, root:shoot dry-weight ratio, root diameter class proportions, and specific root length. For all response variables, the main effect of rootstock and rootstock species was significant (P < 0.05). The main effect of harvest was significant (P < 0.05) for all response variables, with the exception of TRL proportion in diameter class 2. ‘Ferro’ rootstock produced the largest TRL and root surface area, with observed values 122% and 120% greater than the smallest root system (‘Exclamation’ SG), respectively. Among rootstock species, pumpkin produced the largest TRL and root surface area, with observed values 100% and 82% greater than those of watermelon, respectively. These results demonstrate that substantial differences exist during the initial 3 WAT in root system morphology of rootstocks and rootstock species available for watermelon grafting and that morphologic differences of root systems can be characterized using image analysis.

Effect of drought on growth and water use of sugar beet

1987 ◽  
Vol 109 (3) ◽  
pp. 421-435 ◽  
Author(s):  
Kay F. Brown ◽  
A. B. Messem ◽  
R. J. Dunham ◽  
P. V. Biscoe
Keyword(s):  
Sugar Beet ◽  
Root System ◽  
Soil Water ◽  
Water Use ◽  
Dry Matter ◽  
Unit Length ◽  
Fibrous Root ◽  
Deep Soil ◽  
Uptake Rates ◽  
Fibrous Roots

SummaryThe growth and water use of sugar beet affected by early (ED) and late (LD) drought was compared with that of irrigated (I) and unirrigated (NI) controls. Mobile shelters were used to exclude rain from ED plots during June and July, and LD plots during August and September, respectively, whereas outside these periods the ED and LD plots were irrigated as necessary.The ED treatment affected the fibrous roots severely. Many of the roots in the top 60 cm of soil died and development of the root system below this depth was slow. Expansion of the leaf canopy slowed, radiation interception was reduced and the rate of water use fell from about 1·2 times to 0·6 times Penman potential transpiration rate. The LD treatment, which was imposed when the fibrous root system was already extensive, had little effect on the fibrous roots except in the top soil. The accessible soil water was quickly depleted and the resulting stress was accompanied by earlier senescence of leaves. The rate of converting intercepted light to crop dry matter was reduced in both treatments. However, the ED treatment was the most detrimental because the amount of light intercepted in the months of highest radiation was greatly reduced owing to the restricted leaf cover. The relative effects on growth are reflected in the final sugar yields which were 8·7, 10·5, 9·9 and 12·0 (±0·30) t/ha in the ED, LD, NI and I treatments respectively.More of the deep soil water was used in the drought-affected plots (particularly LD) than in the irrigated controls. Maximum depths of water extraction were 140–150 cm in ED and I plots and > 170 cm in LD plots. The highest uptake rates per unit length of root (20–40 μl/cm per day) were measured in the deepest part of the root system. At all depths, uptake rates declined as the soil dried. After correcting for overestimated water use where necessary, the ratios of final dry matter and sugar yields respectively to season-long water use (June–October) were close to 1·4 and 0·8 t/ha per 25 mm for all four treatments.

Root length density and soil water distribution in drip-irrigated olive orchards in Argentina under arid conditions

2009 ◽  
Vol 60 (3) ◽  
pp. 280 ◽  
Author(s):  
Peter S. Searles ◽  
Diego A. Saravia ◽  
M. Cecilia Rousseaux
Keyword(s):  
Water Content ◽  
Root System ◽  
Soil Water ◽  
Soil Water Content ◽  
Root Length ◽  
Root Length Density ◽  
Soil Depth ◽  
Drip Line ◽  
North West ◽  
Intensively Managed

Several studies have evaluated many above-ground aspects of olive production, but essential root system characteristics have been little examined. The objective of our study was to evaluate root length density (RLD) and root distribution relative to soil water content in three commercial orchards (north-west Argentina). Depending on the orchard, the different drip emitter arrangements included either: (1) emitters spaced continuously at 1-m intervals along the drip line (CE-4; 4 emitters per tree); (2) 4 emitters per tree spaced at 1-m intervals, but with a space of 2 m between emitters of neighbouring trees (E-4); or (3) 2 emitters per tree with 4 m between emitters of neighbouring trees (E-2). All of the orchards included either var. Manzanilla fina or Manzanilla reina trees (5–8 years old) growing in sandy soils, although the specific characteristics of each orchard differed. Root length density values (2.5–3.5 cm/cm3) in the upper soil depth (0–0.5 m) were fairly uniform along the drip line in the continuous emitter (CE-4) orchard. In contrast, roots were more concentrated in the E-4 and E-2 orchards, in some cases with maximum RLD values of up to 7 cm/cm3. Approximately 70% of the root system was located in the upper 0.5 m of soil depth, and most of the roots were within 0.5 m of the drip line. For each of the three orchards, significant linear relationships between soil water content and RLD were detected based on 42 sampling positions that included various distances from the trunk and soil depths. Values of RLD averaged over the entire rooting zone and total tree root length per leaf area for the three orchards were estimated to range from 0.19 to 0.48 cm/cm3 and from 1.8 to 3.5 km/m2, respectively. These results should reduce the uncertainty associated with the magnitude of RLD values under drip irrigation as intensively managed olive orchards continue to expand in established and new growing regions.

Effect of nematode infection and damage on the root system and plant growth of three Musa cultivars commonly grown in Uganda

Nematology ◽  
2006 ◽  
Vol 8 (2) ◽  
pp. 177-189 ◽  
Author(s):  
Dirk De Waele ◽  
Paul Speijer ◽  
Clifford Gold ◽  
Rony Swennen ◽  
Herbert Talwana
Keyword(s):  
Root Length ◽  
Field Experiments ◽  
Root Length Density ◽  
Root Systems ◽  
Nematode Species ◽  
Parasitic Nematodes ◽  
Plant Tolerance ◽  
Banana Production ◽  
Primary Roots ◽  
Breeding Programmes

AbstractBanana production in East Africa is threatened by declining yields partly caused by plant-parasitic nematodes. Attempts to ameliorate this damage are hampered by a lack of information on the characteristics of the root systems of healthy and nematode infested roots of commonly grown banana cultivars. An experiment in hydroponic culture, where healthy root systems were established, demonstrated that there were differences in number, size and distribution of primary, secondary and tertiary roots among the cultivars Nabusa, Pisang Awak and Sukali Ndizi. Field experiments carried out at three sites in Uganda showed that nematode damage on the same cultivars increased the number of primary roots and root bases, either increased or decreased root length depending on the cultivar or nematode species involved, but always decreased root length density. Root number and size are probably critical factors in determining plant tolerance to nematodes. Our findings should help plant breeding programmes, which must establish those selection criteria that are most likely to reduce the debilitating effects of nematode damage.

scholarly journals Analysis on root system morphology using a root length density model. I. The model.

1988 ◽  
Vol 57 (4) ◽  
pp. 749-754 ◽  
Author(s):  
Tetsuya SUGA ◽  
Keisuke NEMOTO ◽  
Jun ABE ◽  
Shigenori MORITA
Keyword(s):  
Root System ◽  
Root Length ◽  
Root Length Density ◽  
Density Model
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