Dark Island heath (Ninety-mile Plain, South Australia). III. The root systems

1957 ◽  
Vol 5 (1) ◽  
pp. 103 ◽  
Author(s):  
RL Specht ◽  
P Rayson
Keyword(s):  
Root System ◽  
Root Nodules ◽  
Morphological Characteristics ◽  
South Australia ◽  
Dry Weight ◽  
Root Systems ◽  
The Other ◽  
Fibrous Root ◽  
Tap Root ◽  
Heath Community

This paper describes the nature of the root systems of the most important members of the heath community. Several variations of tap-root and fibrous root systems were observed. Tap-rooted species were either shallow rooting (1–2 ft) or deep rooting (6 or more feet into the clay subsoil). Two variations of deep tap-rooted species were observed. The tap-root of one decays with age; the laterals of the other produce frequent sucker shoots. In all forms of the deep tap-rooted species an extensive lateral root system was developed within the surface 12 in. of soil — the organic A1 horizon; the tap-root and occasional secondary vertical descended, often unbranched, to the subsoil. The fibrous root system may arise from stem bases, rhizomes, tubers, or underground stocks (caudices). With the exception of underground stocks, which had extensive roots in the A2 and A3 to B horizons, the other forms of the fibrous root systems were confined to the A1 horizon. The marked concentration of roots in the organic A1 horizon was illustrated in dry weight–depth curves. Most of the roots in the A2, and A1 horizons arose from the caudex of Xanthorrhoea australis R.Br.; the remainder were vertical roots which passed directly into the subsoil from the deep-rooted species. About 70 per cent of the species recorded in the heath had morphological characteristics which enabled them to survive a fire and sprout from perennating buds buried under the surface of the ground. Thus, although the aerial organs of the heath were destroyed by fire, the root systems provided a reserve of food and nutrients for the regenerating heath. The dry weight of the root systems was therefore scarcely influenced by fire and thereafter steadily increased in the organic A1 horizon as the stand aged. The presence of root nodules on species of Leguminosae and Casuarinaoeae as well as of haustoria on Exocarpos sparteus R.Br. and Euphrasia collina R.Br. Is recorded.

Root Morphology and Secretion of two subtropical tree species to NH4+-N and NO3–-N Deposition

2020 ◽  
Author(s):  
Rui Zhang ◽  
Yi Wang ◽  
Zhichun Zhou
Keyword(s):  
Root Growth ◽  
Root System ◽  
Root Morphology ◽  
Tree Species ◽  
Southern China ◽  
N Deposition ◽  
Fibrous Root ◽  
Nitrogen And Phosphorus ◽  
Root Absorption ◽  
Tap Root

Abstract Background: Both NH4+ and NO3– are capable of greatly influencing plants’ growth and biomass. However, the belowground responses of subtropical trees to either NH4+ or NO3– deposition remain poorly understood. Here, we discuss how these two forms of N deposition can affect root development, and experimentally analyzed how they could impact nitrogen and phosphorus absorption in two types (broadleaved with a fibrous root system vs. conifer with a tap root system) of subtropical tree species. Results: In a greenhouse in southern China, 1-year-old S. superba and P. massoniana seedlings grown on P-limited and P-normal soil were treated with NaNO3 and NH4Cl solutions of 0, 80, and 200 kg N ha–1 year–1, corresponding to the control, N80, and N200 groups, respectively. Root phenotype characteristics and metabolism ability were measured after 8 months of growth. The results showed that the root morphology and physiology variables differed significantly between the two species under different N and P treatments. Although S. superba had a larger quantity of roots than P. massoniana, both its root growth rate and root absorption were respectively lower and weaker. N addition differentially affected root growth and activity as follows: (1) NO3–-N80 and NH4+-N80 increased root growth and activity of the two species, but NH4+-N80 led to thicker roots in S. superba; (2) NO3–-N200 and NH4+-N200 had inhibitory effects on the roots of P. massoniana, for which NH4+-N200 led to thinner and longer roots and even the death of some roots; and (3) NH4+-N could promote metabolic activity in thicker roots (> 1.5 mm) and the NO3–-N was found to stimulate activity in thinner roots (0.5–1.5 mm) in the fibrous root system having a larger quantity of roots, namely S. superba. By contrast, NO3–-N and NH4+-N had an opposite influence upon functioning in the tap root system with a slender root, namely P. massoniana. Conclusion: We conclude P. massoniana has a much higher root absorption efficiency; however, nitrogen deposition is more beneficial to the root growth of S. superba.

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.

scholarly journals Boron mobility in eucalyptus clones

2009 ◽  
Vol 33 (6) ◽  
pp. 1733-1744 ◽  
Author(s):  
Jackson Freitas Brilhante de São José ◽  
Ivo Ribeiro da Silva ◽  
Nairam Felix de Barros ◽  
Roberto Ferreira Novais ◽  
Eulene Francisco Silva ◽  
...  
Keyword(s):  
Organic Compound ◽  
Boric Acid ◽  
Root System ◽  
Foliar Application ◽  
Root Systems ◽  
Mature Leaf ◽  
The Other ◽  
B Mobility ◽  
Boron Mobility

Understanding the magnitude of B mobility in eucalyptus may help to select clones that are more efficient for B use and to design new practices of B fertilization. This study consisted of five experiments with three eucalyptus clones (129, 57 and 58) where the response to and mobility of B were evaluated. Results indicated that clone 129 was less sensitive to B deficiency than clones 68 and 57, apparently due to its ability to translocate B previously absorbed via root systems to younger tissues when B in solution became limiting. Translocation also occurred when B was applied as boric acid only once to a single mature leaf, resulting in higher B concentration in roots, stems and younger leaves. The growth of B-deficient plants was also recovere by a single foliar application of B to a mature leaf. This mobility was greater, when foliar-applied B was supplied in complexed (boric acid + manitol) than in non-complexed form (boric acid alone). When the root system of clone 129 was split in two solution compartments, B supplied to one root compartment was translocated to the shoot and back to the roots in the other compartment, improving the B status and growth. Thus, it appears that B is relatively mobile in eucalyptus, especially in clone 129, and its higher mobility could be due to the presence of an organic compound such as manitol, able to complex B.

Morphological and physiological attributes of root systems and seedling growth in three different Picea glauca reforestation stock

2000 ◽  
Vol 30 (11) ◽  
pp. 1669-1681 ◽  
Author(s):  
M J Krasowski ◽  
J N Owens
Keyword(s):  
Root System ◽  
Seedling Growth ◽  
Picea Glauca ◽  
Root Systems ◽  
Growing Season ◽  
System Size ◽  
The Other ◽  
Root Pruning ◽  
Growing Seasons ◽  
Forest Sites

The relationship between certain morphological characteristics of white spruce (Picea glauca (Moench) Voss) planting stock (STK) and post-planting seedling performance was evaluated. Root system size at planting, its expansion, and its capacity to conduct water during the first post-planting weeks were determined. These characteristics were related to the performance of STK planted on two forest sites and measured for three growing seasons and to the performance of seedlings grown in large wooden boxes buried in the soil outdoors for one growing season (grown without competition from other vegetation). The compared STK were (i) polystyroblock grown, (ii) polystyroblock grown with chemical root pruning, and (iii) peat-board grown with mechanical root pruning. After three growing seasons on forest sites, seedlings with mechanically pruned roots grew more above ground than did seedlings from polystyroblock containers. This difference in seedling growth performance was even more significant for seedlings grown in wooden boxes. Of these, the mechanically pruned seedlings grew more not only above the ground but they also produced larger root systems by the end of the first growing season. This was despite the initially significantly smaller root systems of mechanically pruned seedlings, compared with the other two STK. Early (5-7 weeks after planting) post-planting root expansion patterns in the three STK were significantly different, with the roots of mechanically pruned seedlings growing less than the roots in the other two STK. In spite of this, pressure-probe measured hydraulic conductivity and water flux through root systems increased during the first post-planting weeks in mechanically pruned seedlings while declining or changing little in the other two STK. It was concluded that root system size at planting and its early post-planting expansion did not relate well to the root system hydraulic properties or to the post-planting seedling growth performance.

scholarly journals Enriched CO2 and Root-Associated Fungi (Mycorrhizae) Yield Inverse Effects on Plant Mass and Root Morphology in Six Asclepias Species

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2474
Author(s):  
Rondy J. Malik ◽  
James D. Bever
Keyword(s):  
Root Morphology ◽  
Co2 Flux ◽  
Dry Weight ◽  
Strong Positive Correlation ◽  
Fibrous Root ◽  
Native Communities ◽  
Mycorrhizal Associations ◽  
Tap Root ◽  
Order Root ◽  
Enriched Co2

While milkweeds (Asclepias spp.) are important for sustaining biodiversity in marginal ecosystems, CO2 flux may afflict Asclepias species and cause detriment to native communities. Negative CO2-induced effects may be mitigated through mycorrhizal associations. In this study, we sought to determine how mycorrhizae interacts with CO2 to influence Asclepias biomass and root morphology. A broad range of Asclepias species (n = 6) were chosen for this study, including four tap-root species (A. sullivantii, A. syriaca, A. tuberosa, and A. viridis) and two fibrous root species (A. incarnata and A. verticillata). Collectively, the six Asclepias species were manipulated under a 2 × 2 full-factorial design that featured two mycorrhizal levels (−/+ mycorrhizae) and two CO2 levels (ambient and enriched (i.e., 3.5× ambient)). After a duration of 10 months, Asclepias responses were assessed as whole dry weight (i.e., biomass) and relative transportive root. Relative transportive root is the percent difference in the diameter of highest order root (transportive root) versus that of first-order absorptive roots. Results revealed an asymmetrical response, as mycorrhizae increased Asclepias biomass by ~12-fold, while enriched CO2 decreased biomass by about 25%. CO2 did not impact relative transportive roots, but mycorrhizae increased root organ’s response by more than 20%. Interactions with CO2 and mycorrhizae were observed for both biomass and root morphology (i.e., relative transportive root). A gene associated with CO2 fixation (rbcL) revealed that the two fibrous root species formed a phylogenetic clade that was distant from the four tap-root species. The effect of mycorrhizae was most profound in tap-root systems, as mycorrhizae modified the highest order root into tuber-like structures. A strong positive correlation was observed with biomass and relative transportive root. This study elucidates the interplay with roots, mycorrhizae, and CO2, while providing a potential pathway for mycorrhizae to ameliorate CO2 induced effects.

scholarly journals Soybean Inoculant Types and Rates Evaluated under Dry and Irrigated Field Conditions

1969 ◽  
Vol 66 (4) ◽  
pp. 241-249 ◽  
Author(s):  
R. S. Smith ◽  
G. A. Del Río Escurra
Keyword(s):  
Root Nodules ◽  
Dry Weight ◽  
Application Rate ◽  
Rhizobium Japonicum ◽  
Tap Root ◽  
Standard Application ◽  
Glycine Max L ◽  
Standard Rate ◽  
Soil Inoculant ◽  
High Soil Temperature

Effects of high soil temperature and low soil moisture for 7 days following planting were utilized in evaluating inoculant types and inoculating rates with soybeans (Glycine max (L.) Merr.) grown in a soil free of Rhizobium japonicum in Puerto Rico. Granular soil inoculant applied at 10 times the standard application rate provided significantly more tap root and total number of nodules than all other treatments. This increase was observed in sampling at 32 and 98 days after planting under both dry and irrigated conditions. The total of all inoculating types applied at 10 times the rate provided a significant increase in number of tap root nodules, total number of nodules and nodule dry weight per plant only at 32 days when compared with the total for application at the standard rate. Sampling at both 32 and 98 days indicated a significant increase in number of tap root nodules, total number of nodules and nodule dry weight per plant with irrigation when compared to the dry section.

Grain yield and flowering of some introduced grain legumes in South Australia

1975 ◽  
Vol 15 (75) ◽  
pp. 556 ◽  
Author(s):  
JH Silsbury
Keyword(s):  
Grain Yield ◽  
Dry Matter ◽  
South Australia ◽  
Dry Weight ◽  
Grain Legumes ◽  
The Other ◽  
Shoot Dry Weight ◽  
Matter Production ◽  
Lathyrus Cicera ◽  
Genotype A

Data are presented for time of flowering, total shoot dry weight and grain yield of White Brunswick pea (Pisum sativum), six introduced peas and one introduction each of Lathyrus sativus and Lathyrus cicera from ten plot experiments conducted in South Australia over the period 1955-1 960.None of the introduced legumes flowered earlier than White Brunswick peas and only one, possibly, has a greater capacity for higher grain yield. L. cicera on the other hand gave 25 per cent greater yield over all sites and seasons with an average of 2.84 tonne ha-1.The ratio between grain yield and total shoot dry weight varied with genotype and between seasons with a genotype. A low ratio was not always associated with low dry matter production.

Mycorrhizal dependence and growth habit of warm-season and cool-season tallgrass prairie plants

1988 ◽  
Vol 66 (7) ◽  
pp. 1376-1380 ◽  
Author(s):  
B. A. Daniels Hetrick ◽  
D. Gerschefske Kitt ◽  
G. Thompson Wilson
Keyword(s):  
Tallgrass Prairie ◽  
Mycorrhizal Fungi ◽  
Warm Season ◽  
Dry Weight ◽  
Root Systems ◽  
Mycorrhizal Symbiosis ◽  
Photosynthetic Pathway ◽  
Fibrous Root ◽  
Cool Season ◽  
Warm Season Grasses

Warm-season (C4) and cool-season (C3) mycorrhizal grasses were 63–215 and 0.12–4.1 times larger in dry weight than non-inoculated controls, respectively. Nonmycorrhizal warm-season plants did not grow and frequently died, while cool-season plants grew moderately well in the absence of mycorrhizal symbiosis. Like warm-season grasses, tallgrass prairie forbs were highly dependent on mycorrhizal symbiosis, even though they are not known to employ the C4 photosynthetic pathway. Thus, phenology may be more critical than photosynthetic pathway in determining mycorrhizal dependence. Warm-season grasses and forbs had coarser, less frequently branched root systems than cool-season grasses, supporting the hypothesis that mycorrhizal dependence is related to root morphology. Cool-season grasses may have developed more fibrous root systems because mycorrhizal nutrient uptake was not effective in the colder temperate environment in which they evolved. In contrast, warm-season plants and dependence on mycorrhizal fungi may have coevolved, because both symbionts are of tropical origin.

Comparative Leaf Water Potentiais of Plants in Burnt and Unburnt Dry Sclerophyll Vegetation

1993 ◽  
Vol 41 (6) ◽  
pp. 661 ◽  
Author(s):  
JM Guo ◽  
R Sinclair
Keyword(s):  
Surface Soil ◽  
South Australia ◽  
Root Systems ◽  
The Other ◽  
Burnt Area ◽  
Burnt Site ◽  
Water Potentials ◽  
And Control ◽  
Intact Root ◽  
Sampling Times

Leaf (xylem) water potentials were measured in summer and autumn on four species, Eucalyptus fasciculosa, Pultenaea daphnoides, Platylobium obtusangulum and Acacia myrtifolia growing in the understorey of sclerophyll stringybark vegetation in the Mt Lofty Ranges, South Australia. Plants regenerating in an area burnt by bushfire 2 years previously were compared with plants in an adjacent unburnt area. The Acacia was killed by fire and subsequently regenerated from seed. The other three species survived and resprouted from basal or epicormic buds. It was expected that shrubs regenerating from basal buds would be better hydrated in summer, as a large intact root system would supply a reduced canopy, and that seedlings, with smaller root systems than unburnt adults, would be more stressed. The Acacia was indeed significantly more stressed during summer in the burnt area. However the Platylobium was also more stressed than the controls, while the Pultenaea showed no significant differences between burnt and control areas. The Eucalyptus showed no differences between sites, nor between any of the three sampling times. The more negative water potentials of some of the regenerating plants are explained by greater exposure of surface soil on the burnt site, leading to more rapid drying of the surface soil in summer.

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.

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