Percentage Of Total Root Length Research Articles

Detection of Bone Loss With Different X‐Ray Techniques in Periodontal Patients

Intraoral radiographs can aid in formulating a more accurate diagnosis of periodontal disease. However, it must be considered whether a comparable amount of information can be obtained with modern panoramic radiographs. The aim of this study was to determine to what degree the diagnosable amount of bone loss in patients with aggressive periodontitis or severe chronic periodontitis depends on the type of x-ray technique used. A total of 110 subjects (63 females) were included in this study. The inclusion criteria were the diagnosis of aggressive periodontitis (N = 49) or severe chronic periodontitis (N = 61). In all patients, panoramic radiographs (panoramic) and intraoral films of all regions (eight to 10 single exposures) were available. Analysis of the panoramic and intraoral films was carried out with a computer-assisted technique for linear measurement. The amount of bone loss in reference to the alveolar crest (AC) and bottom of the bony defect (BD) was determined as a percentage of total root length. Depending on the examined tooth and reference point, 47.01% to 81.89% of all subjects showed differences between intraoral and panoramic measurements that were < or =10% of the total root length. For cemento-enamel junction-AC measurements, differences between intraoral and panoramic measurements that were >10% of the total root length were found predominantly in the upper molar and premolar regions. In the mandible, differences between intraoral and panoramic measurements that were >10% of the total root length were observed for BD and AC at the mesial contour of the central incisor. A preorientation with respect to the expected bone loss is possible using panoramic radiographs. Additional intraoral films might be helpful where rapid changes of bone level are expected (e.g., aggressive periodontitis).

Tooth movement characteristics in relation to root resorption in young and adult rats

The aim of this study was to investigate tooth movement characteristics in relation to root resorption in young and adult rats. Two groups of 30 rats each (aged 6 wk and 9-12 months, respectively) were used. Standardized orthodontic appliances were placed to move the maxillary molars mesially. Animals were killed 1, 2, 4, 8, and 12 wk after the beginning of the experiment and their jaws were processed for histomorphometric analysis. In parasagittal sections of 'pressure zones' the extent of root resorption was measured and expressed as percentage of total root length. Whereas a negative correlation was found between the velocity of tooth movement and the extent of root resorption, a positive correlation was noted between the amount/duration of tooth movement and root resorption, but only in adult rats. The duration of tooth movement showed the highest correlation coefficient and the smallest 95% confidence interval. In younger animals, correlations were weak, and other factors are likely to be involved in the individual susceptibility to root resorption.

Distinguishing between metabolically active and inactive roots by combined staining with 2,3,5-triphenyltetrazolium chloride and image colour analysis

The objective of the present work was to develop a method to distinguish between metabolically inactive and active parts of plant roots. White clover (Trifolium repens L.) roots were stained with 2,3,5-triphenyltetrazolium chloride (TTC) followed by root colour classification with an interactive scanner-based image analysis programme (WinRHIZO). Roots inactivated by boiling were unstained and pale brown, whereas fresh samples with predominantly metabolically active roots turned dark red, red or pale red after staining. A small amount of very young, presumable active roots (0.8% of total active root length) failed to stain red with TTC. The colour analysis of inactive and active roots was based on four colour classes for boiled roots and seven classes for fresh roots, respectively, as defined upon visual examination of images. Pixel colours falling outside the defined classes were allocated to the nearest defined class – an option that increased objectivity and stability and reduced the required number of colour classes. For the fresh white clover roots, 75–86% of the total root length was determined as active, while 3–7% of the boiled roots fell into the same category. The percentage of total root length measured by WinRHIZO that was identified as metabolically active was linearly correlated with the percentage of fresh roots in mixtures of fresh and boiled roots (R2=0.99). Colour classes chosen a priori from one experiment could be used to distinguish fairly satisfactorily between active and inactive roots of another white clover cultivar grown under other conditions, but failed to classify activity in ryegrass (Lolium multiflorum Lam.) root samples. In the latter case, colour classes needed to be re-defined in order to produce reliable data. Our work shows that WinRHIZO’s colour identification sub-module provides a new promising tool to classify root activity as identified after staining with TTC, but colour classes must be carefully evaluated on every new occasion.

Growth and reproductive characteristics of the columnar cactus Stenocereus queretaroensis and their relationships with environmental factors and colonization by arbuscular mycorrhizae.

Three natural populations of pitayo (Stenocereus queretaroensis (Weber) Buxbaum), a columnar arborescent cactus, were studied in their subtropical environments in western Mexico. All of the sites were characterized by shallow, nutrient-poor soils. Percentage of colonization by arbuscular mycorrhizae (AM) fungi, stem growth, fruit mass, and percentage germination were greater in S. queretaroensis at Autlan, Jalisco (AJ) than at Zacoalco de Torres, Jalisco (ZTJ) or Santa Rosa, Zacatecas (SRZ). The onset of root colonization by arbuscular mycorrhizae during the middle of the summer wet period preceded increases in stem extension rate and stem phosphorus concentration. Based on previous studies of effects of environmental factors on photosynthesis, climatic conditions were more favorable for photosynthesis at AJ than at SRZ and ZTJ, as indicated by the amount of summer rainfall, the amount of light, and the moderate air temperatures that prevailed during the fall and winter seasons. There was a significant positive correlation between stem growth and percentage of total root length colonized by arbuscules of AM fungi for S. queretaroensis at SRZ and AJ, but not at ZTJ. A negative significant correlation was observed between stem growth and maximal and minimal air temperatures at the three study sites. Stem growth was positively related to rainfall only at SRZ, and light was statistically related to stem growth only at ZTJ. Among sites, S. queretaroensis at AJ had the highest carbon gain and greatest AM colonization, creating physiological conditions that led to the highest stem growth, fruit mass and percentage of seed germination.

748 PB 108 THE RELATIONSHIP BETWEEN ROOT HAIR DEVELOPMENT AND OTHER ROOT ATTRIBUTES IN CITRUS AND CITRUS RELATIVES

The relationship of genotypic variation in root hair development with root proliferation, mycorrhizal colonization, and specific root length (length / dry mass) was studied in sixteen field-grown citrus relatives. The species varied widely in hair development, root length and mass density, and specific root length. No correlation was found between hair development, mycorrhizal colonization, root proliferation, and specific root length. However, there was a significant correlation (r=.55) between the percentage of total root length with hairs and the percentage of hairs with adhered soil. In a second experiment, the phenotypic plasticity in root hair development was studied in four-citrus rootstooks: Swingle citsumelo, Sour orange, Trifoliate orange and Volkamer lemon. Roots were grow” in either mineral soil or high organic matter media. After eight weeks, root length density and percentage of root length with hairs averaged over all four rootstocks was 232 % and 85 % greater in the organic media than in the mineral soil. Similar to the first experiment the percentage of total root length with hairs was significantly correlated (r=.99) with the percentage of hairs with adhered soil.

Plant Form In Relation To Root Spread

Abstract Four Juniperus chinensis cultivars, ‘Torulosa’, ‘Sylvestris’, ‘Pfitzeriana’ and ‘Hetzii’ had mean and maximum root spreads of 1.6m (4.8 ft) and 2.2 m (6.6 ft) resp, 12 months after planting. Despite large differences in plant form, root spread on all four cultivars was equal. The columnar cultivar ‘Torulosa’ had significantly less root length within the drip-line than the more spreading cultivars ‘Pfitzeriana’ and ‘Hetzii’. Percentage of total root length within the dripline was correlated (r= −.72) with the ratio of plant height to spread.

Interaction between Glomus mosseae and Erwinia carotovora and its effects on the growth of tomato plants

summaryThe effect of inoculation with Erwinia carotovora pv. carotovora on tomatoes with or without VA mycorrhizal infection by Glomus mosseae was studied in a greenhouse trial. E. carotovora decreased the growth of nonmycorrhizal tomato plants, but neither growth nor the percentage of total root length with VA infection were reduced in mycorrhizal plants. Protection of tomato against the pathogen and reduction in the number of colony‐forming units of E. carotovora in the rhizosphere of mycorrhizal plants were independent of concentration of P in the plant and the timing of inoculation with the two microorganisms. The possible mechanisms of the resistance induced in tomato plants by G. mosseae against E. carotovora are discussed.

Effect of soil moisture and phosphate level on root hair growth of corn roots

Root hairs have been shown to enhance P uptake by plants growing in low P soil. Little is known of the factors controlling root hair growth. The objective of this study was to investigate the influence of soil moisture and P level on root hair growth of corn (Zea mays L.). The effect of volumetric soil moistures of 22% (M0), 27% (M1), and 32% (M2) and soil (Raub silt loam, Aquic Argiudoll) P levels of, 0.81 (P0), 12.1 (P1), 21.6 (P2), 48.7 (P3), and 203.3 (P4) μmol P L−1 initially in the soil solution, on shoot and root growth, P uptake, and root hair growth of corn was studied in a series of pot experiments in a controlled climate chamber. Root hair growth was affected more by soil moisture than soil P. The percentage of total root length with root hairs and the density and length of root hairs on the root sections having root hairs all increased as soil moisture was reduced from M2 to M0. No relationship was found between root hair length and soil P. Density of root hairs, however, was found to decrease with an increase in soil P. No correlation was found between root hair growth parameters and plant P content, further suggesting P plays a secondary role to moisture in regulating root hair growth in soils. The increase in root hair growth appears to be a response by the plant to stress as yield and P uptake by corn grown at M0 were only 0.47 to 0.82, and 0.34 to 0.74, respectively, of that measured at M1 across the five soil P levels. The increase in root hair growth at M0, which represents an increase of 2.76 to 4.03 in root surface area, could offset, in part, the reduced rate of root growth, which was the primary reason for reduced P uptake under limited soil moisture conditions.

Root Growth and Water Uptake by Maize Plants in Drying Soil

Sharp, R. E and Da vies, W. J. 1985. Root growth and water uptake by maize plants in drying soil.— J. exp. Bot. 36: 1441-1456. The influence of soil drying on maize (Zea mays L.) root distribution and use of soil water was examined using plants growing in the greenhouse in soil columns. The roots of plants which were watered well throughout the 18 d experimental period penetrated the soil profile to a depth of 60 cm while the greatest percentage of total root length was between 20-40 cm. High soil water depletion rates corresponded with these high root densities. Withholding water greatly restricted root proliferation in the upper part of the profile, but resulted in deeper penetration and higher soil water depletion rates at depth, compared with the well watered columns. The deep roots of the unwatered plants exhibited very high soil water depletion rates per unit root length.

Comparison of root and root hair growth in solution and soil culture

Abstract Aerated solution culture is frequently used for studying plant growth. Few comparisons have been made of root growth in solution with that found in soil. The objective of this study was to compare root growth and root hair development in these two mediums. Corn (Zea mays L.) grown in aerated solution at two temperatures (18 and 25°C) and three P concentrations (2, 10, and 500 μmol L‐1) was compared with that in three soils, Raub (Aquic Argiudoll) and two Chalmers (Typic Haplaquoll) silt loams, in a controlled climate chamber over 21d. Corn plant weight and root growth were similar in solution culture and Raub soil when grown at an air and soil temperature of 18°C. At 25°C both yield and root growth were greater in Raub soil, even though P uptake by corn was 7‐fold greater in solution culture. The same difference was found when corn grown at 25°C in solution culture at 3 different P concentrations was compared with that grown in Chalmers soil at two P levels. Percentage of total root length with root hairs, root length and density and consequently root surface area, were all greater in the Chalmers soil than in solution culture. An increase in soil P, resulted in a decrease in root hair growth. No such relationship was found in solution culture. Although the recovery and measurement of plant roots and root hairs is more convenient in solution culture, results from this study indicate that the usefulness of solution culture for determining those factors which control root growth and root hair development in soil is limited.

Mycorrhizal Influence on the Nutrition of Strawberries1

Abstract Strawberries (Fragaria × ananassa Duch. cv. Hood) were grown at three levels of soil P and inoculated with either Glomus fasciculatus (Thaxter sensu Gerd.) Gerd. &amp; Trappe or Gigaspora calospora (Nicol. &amp; Gerd.) Gerd. &amp; Trappe mycorrhizal fungus. P and N concentration in the aerial part of inoculated plants were higher than in controls; highest concentrations were found in plants inoculated with Glomus fasciculatus. Inoculation with this fungus also resulted in the greatest length of mycorrhizal roots and the highest percentage of total root length infected.