scholarly journals Ability of Citrus Root System to Overcome a Strong Wax Layer

2018 ◽  
Vol 10 (10) ◽  
pp. 213 ◽  
Author(s):  
L. B. de Oliveira ◽  
M. A. Coelho Filho ◽  
S. S. Arriero ◽  
F. A. Gomes Júnior ◽  
A. M. W. Cova ◽  
...  

The present work aimed to investigate the effects of mechanical impedance of wax layer (wax discs were installed 0.1 m deep) on root system deepening of citrus seedlings growing in columns with sand and nutrient solution. Two planting systems were evaluated: direct seeding (DS) and planting of seedlings (PS) (plants obtained from seed germination in tubes). Two experiments were carried out in a sequence: first to investigate the wax layer resistance levels (0.14 to 2.7 MPa) on root system penetration and two planting systems (DS and PS). The second evaluated the root and plant development of the two planting systems and two resistance of wax layer to root penetration: control (0.14 MPa) and a strong wax layer (1.06 MPa). The experimental design was randomized blocks, the first experiment in a 2 × 4 factorial scheme with 4 replications and the second a 2 × 2 factorial scheme with 6 replications. Resistance level ≥ 1.52 MPa (60% hard wax and 40% soft wax) completely limited root penetration in the artificial strong layer. The presence of strong wax disc reduced the citrus root system in both planting systems. PS was associated with greater root and shoot vigor, indicating that, in soils with good physical structure and porosity or allowing root deepening beyond the cohesive layer, this planting system is fully adequate, despite the possible benefit of not cutting the pivoting root in direct sowing.

2021 ◽  
Author(s):  
Elohim Bello Bello ◽  
Thelma Y. Rico Cambron ◽  
Ruben Rellan Alvarez ◽  
Luis Rafael Herrera-Estrella

Soil mechanical impedance precludes root penetration, confining root system development to shallow soil horizons where mobile nutrients are scarce. Using a two-phase-agar system, we characterized Arabidopsis thaliana responses to low and high mechanical impedance at three root penetration stages. We found that seedlings whose roots fail to penetrate agar barriers show drastic changes in shoot and root morphology, while those capable of penetrating have only minor morphological effects. The assessment of 21 Arabidopsis accessions revealed that primary root penetrability (PRP) varies widely among accessions. To search for quantitative trait loci (QTLs) associated to root system penetrability, we evaluated a recombinant inbred population (RIL) derived from Landsberg erecta (Ler-0, with a high PRP) and Shahdara (Sha, with a low PRP) accessions. QTL analysis revealed a major-effect QTL localized in chromosome 3 (q-RPI3), which accounted for 29.98% (LOD = 8.82) of the total phenotypic variation. Employing an introgression line (IL-321), with a homozygous q-RPI3 region from Sha in the Ler-0 genetic background, we demonstrated that q-RPI3 plays a crucial role in root penetrability. This multiscale study revels new insights into root plasticity during the penetration process in hard agar layers, natural variation and genetic architecture behind primary root penetrability in Arabidopsis.


1934 ◽  
Vol 10 (1) ◽  
pp. 77-94 ◽  
Author(s):  
T. K. Pavlychenko ◽  
J. B. Harrington

The results of a study of the competing abilities of certain weeds and crop plants are presented. Characteristics studied as possible indicators of competitive efficiency were development of assimilation surface, stomatal number, readiness and uniformity of seed germination and distribution and penetration of root systems.It is shown that success in competition depends on readiness and uniformity of germination under adverse moisture conditions, the ability to develop a large assimilation surface in the early seedling stage, the possession of a large number of stomata and a root system with a large mass of fibre close to the surface but with its main roots penetrating deeply.Cereal crops were classified in the order of competing ability as follows:— barley, rye, wheat and oats, flax. Brassica arvensis and Avena falua were the most vigorous competitors among the weeds studied.


1993 ◽  
Vol 41 (2) ◽  
pp. 169 ◽  
Author(s):  
M Battaglia ◽  
JB Reid

The correlation between microsite and seedling numbers was determined in field sowings, and the impact of microsites on germination and seedling survival tested in artificial seedbeds in the glasshouse. Small scale variation in soil conditions, at the scale of tens of centimetres, markedly affected the germination and establishment of Eucalyptus delegatensis R.T.Baker seeds and seedlings. Under conditions of limiting soil moisture, microsites that afforded protection, and probably resulted in increased humidity, caused a marked increase in germination number and rate. The mean survival time was significantly higher on these protected microsites than on less protected microsites, or on microsites that restricted root penetration. The importance of this variability in microtopography was strongly influenced by season and the level of environmental stress, and was diminished as seedlings aged. Due to the different requirements for seed germination and seedling growth, a favourable microsite for germination was not necessarily a favourable site for seedling survival. A comparison of seed and seedling responses to water stress indicated that for E. delegatensis, at least, selection due to microsite differences at the time of germination may not have an impact on the developmental characteristics of the seedlings.


Author(s):  
K.K. Srivastava ◽  
P. Barman ◽  
D. Kumar

Background: Availability of quality planting materials is the major impediment in extension of cultivation of low chilling peach in northern plans. Plum suckers are mostly used as rootstocks for raising peach; however nematode infestation is a major problem. Seeds of all peach cultivars do not germinate under subtropical climate of plains of Northern India. Hence, an experiment was carried out at ICAR-CISH, Lucknow on seed germination and subsequent growth of seedlings of low chilling peaches.Methods: Fully mature seeds of peach cv. Florda Prince, Pant Peach 1 and Sharbati were collected during June. Some of the seeds were sown direct in-situ during 1st week of December and remaining seeds were sown in the field after 2 months of stratification in the refrigerator at 7-8°C.Result: Stratification had significant effect on seed germination and late matured peach cv. ‘Sharbati’ exhibited higher seed germination. Good linear seedling growth and maximum percentage of buddable seedlings was found in stratified sown seeds of ‘Sharbati’ peach. Thus the study indicated that harvesting of ‘Sharbati’ and ‘Pant Peach-1’ seeds can be done during June and pre-sown stratification is necessary for better germination and growth of seedlings under subtropical climate of Lucknow.


Nematology ◽  
2019 ◽  
Vol 21 (5) ◽  
pp. 489-496 ◽  
Author(s):  
Gaku Murata ◽  
Tomoyuki Takai ◽  
Kenta Uesugi

Summary Commercially available sorghum cultivars were tested for resistance to Meloidogyne incognita in order to select cultivars that combine fodder production with M. incognita population management. Initially in a pot test with 12 sorghum cultivars, ‘Kyushuko 3 go’, a sorghum hybrid, supported very low M. incognita reproduction approximately 40 days after inoculation (dai) with 500 second-stage juveniles (J2) pot−1, similar to the resistant green manure ‘Tsuchitaro’. Further tests for development of M. incognita in roots (20 dai with 150 J2 (root system)−1) indicated that the resistance of ‘Kyushuko 3 go’ acts after nematode root penetration. In field tests in 2015 and 2016, ‘Kyushuko 3 go’ suppressed M. incognita population densities, although some variations in field conditions may influence reproduction of M. incognita on ‘Kyushuko 3 go’. These findings demonstrated M. incognita-resistant fodder sorghum cultivars could be a useful alternative to susceptible cultivars for root-knot nematode management.


1993 ◽  
Vol 44 (6) ◽  
pp. 1273 ◽  
Author(s):  
M Dracup ◽  
PJ Gregory ◽  
RK Belford

Yellow duplex soils are the dominant soil type in the cropping region of Western Australia, but crop yields on these soils are often variable and below potential. We are seeking to understand the causes of the spatially variable crop growth, and a preliminary study conducted in 1988 at a site east of Beverley indicated that variable shoot growth was associated with variable early (< 6 weeks after sowing) root growth in the sandy A horizon. The present study aimed to identify the constraints to early root growth by locating the position in the A horizon where root growth becomes restricted and measuring the local soil properties. In poor growth areas, root penetration slowed markedly at about 15 cm (about 2 weeks after sowing), while in the good growth areas roots continued to grow downwards at about 8 mm day-1 for lupin and 4 mm day-' for wheat. The soil was a particularly difficult environment for root growth, with generally low pH, low K and B, low porosity and aeration and high strength. Roots in poor growth areas appeared to experience greater mechanical impedance than in the good areas, most likely due to much lower clay contents leading to higher frictional resistance to particle movement or less stability of soil pores created by past roots or fauna.


Nematology ◽  
2006 ◽  
Vol 8 (6) ◽  
pp. 847-852 ◽  
Author(s):  
Tam Vu ◽  
Richard Sikora ◽  
Rüdiger Hauschild

AbstractFour mutualistic endophytic fungal isolates were investigated for their ability to induce systemic resistance in banana toward the burrowing nematode, Radopholus similis in glasshouse experiments. Two isolates of Fusarium oxysporum and one of F. cf. diversisporum isolated from the cortical tissue of banana, and another isolate of F. oxysporum isolated from tomato, were compared. When the root systems of seedling banana plants were pre-inoculated with the four endophytic fungi, R. similis root penetration was reduced by 29-39% and 22-41% 5 and 15 days after nematode inoculation, respectively. Induction of systemic resistance to R. similis in banana roots by the same endophytic fungi was tested in a split-root system. Depending on the isolate, the penetration rates decreased between 30-38.5% and 26.7-45% after 5 and 15 days in the untreated half of the split-root system of plants treated with the endophytic strains when compared to those treated without the fungi. This is the first time that systemic resistance induced by a fungal endophyte has been demonstrated in banana.


Irriga ◽  
2004 ◽  
Vol 9 (3) ◽  
pp. 270-281 ◽  
Author(s):  
José Alves Júnior ◽  
Mateus Dos Santos Lourenção ◽  
Tonny José Araújo da Silva ◽  
Cláudio Ricardo da Silva ◽  
Marcos Vinícius Folegatti

DISTRIBUIÇÃO DO SISTEMA RADICULAR DE PLANTAS JOVENS DE LIMA ÁCIDA ‘TAHITI’ SOB DIFERENTES NÍVEIS DE IRRIGAÇÃO   José Alves Júnior; Mateus dos Santos Lourenção; Tonny José Araújo da Silva; Cláudio Ricardo da Silva; Marcos Vinícius FolegattiDepartamento de Engenharia Rural, Escola Superior de Agricultura “ Luiz de Queiroz”, Universidade de São Paulo, Piracicaba-SP, [email protected]   1 RESUMO  O objetivo deste estudo foi avaliar a distribuição do sistema radicular de lima ácida ‘Tahiti’ (Citrus latifolia Tan), irrigada por gotejamento, sob o efeito de diferentes lâminas de irrigação em condições de campo. O delineamento experimental foi inteiramente casualizado em duas repetições com arranjo fatorial de cinco lâminas de irrigação (0%; 25%; 50%; 75% e 100% da evapotranspiração da cultura medida em um lisímetro de pesagem), duas profundidades (0,0-0,3 e 0,3-0,6 m) e quatro pontos de amostragem (0,3; 0,6; 0,9 e 1,2 m de distância do tronco). A análise foi realizada em um pomar com 30 meses de idade e 17 meses de fornecimento das diferentes lâminas de irrigação. Os resultados mostraram que não houve diferenças entre as lâminas quanto à distribuição das raízes em profundidade, concentrando-se na camada de 0,0-0,3m. Entretanto, a distribuição horizontal foi maior nos níveis baixos (0%; 25% e 50%) do que nos maiores níveis (75% e 100%). Nas plantas irrigadas com 75% e 100% houve concentração das raízes até 0,6 m, indicando que o déficit hídrico induziu o crescimento horizontal das raízes.  UNITERMOS: citros; raiz; manejo da irrigação; Citrus latifolia Tan   ALVES JUNIOR, J.; LOURENÇÃO, M.S.; SILVA, T.J.A.; SILVA, C.R.; FOLEGATTI, M.V. ROOT SYSTEM DISTRIBUTION OF YOUNG ‘TAHITI’ ACID LIME TREES UNDER DIFFERENT LEVELS OF IRRIGATION   2 ABSTRACT  The aim of this study was to evaluate the root system distribution of young ‘Tahiti’ (Citrus latifolia Tan) acid lime irrigated by drip system under field conditions. The experiment was carried out in a factorial design with two replications that consisted of five levels of irrigation (0%, 25%, 50%, 75% and 100% of crop evapotranspiration measured by a weighing lysimeter) and two depths (0.,0-0.3 and 0.3-0.6 m) as well as four horizontal sample points (0.3; 0.6; 0.9 and 1.2 m of distance from trunk). The analysis was carried out in a 30-month-old orchard and  17 months after the beginning of irrigation levels. The results showed that there were no differences in root distribution as to depths, most of them at 0.0-0.3m. However, the horizontal distribution was bigger at lower levels (0, 25 and 50%) than in the highest levels (75 and 100%). In the latter, root concentration reached up to 0.6m, indicating that water stress induced the root growth horizontally  KEYWORDS: citrus; root; irrigation management; Citrus latifolia Tan


Author(s):  
М. М. Маренич ◽  
С. О. Юрченко

В лабораторних і польових дослідах досліджували вплив різних концентрацій біологічно активних речовин, протруйників та їх композицій на лабораторну і польову схожість насіння, розвиток рослин на початкових стадіях розвитку. Встановлено, що застосування протруйників може не зменшувати енергію проростання насіння, але біологічно активні речовини стимулювали цей показник. Застосування гумінових стимуляторів росту сприяло як збільшенню показника енергії проростання, так і інтенсифікації процесів росту та розвитку рослин. Обробка насіння радостимом сприяла збільшенню польової схожості на 2–4 %, а у варіантах з лігногуматом натрію – на 5–6 %. Застосування у рекомендованих дозах для обробки насіння сприяло збільшенню польової схожості на 7–9 % для «Гуміфілда» і на 10–15 % для «1R Seedtreatment». У варіантах з радостимом абсолютно суха маса надземної частини рослин зросла на 13,8–20,6 %, а маса кореневої системи – на 16–25 %. Обробка насіння лігногуматом сприяла збільшенню маси надземної частини і кореневої системи відповідно на 17–19,5 % і 12,7–31 %. У варіантах з гуміфілдом зростання надземної частини становило в середньому 24,8 %, а кореневої системи – 26,3 %, а в разі застосування більшої удвічі дози «1R Seedtreatment» – відповідно 37,5 і 40,6 %! На варіантах, де застосовувалася суміш   «Максим Стар 025 FS», 1,5 л/т + «Гуміфілд» 0,5 л/т в середньому зафіксували збільшення маси надземної частини на 13,9 % та кореневої системи на 15,4 %, а на варіантах із сумішшю «Максим Стар 025 FS», 1,5 л/т + 1R 1,0 л/т – 25,6 і 26,2 % відповідно. Зроблено висновок про доцільність комбінування сумішей для допосівної обробки насіння з метою зменшення негативного впливу протруйників на показники енергії проростання та польової схожості рослин. In laboratory and field experiments we studied influencing of different concentrations of biologically active substances, disinfectants and their compositions on laboratory and field seed germination, development of plants on the initial stages of development. We found that application of disinfectants can not diminish germination energy of seed, but biologically active substances stimulated this index. Humic growth stimulators contributed  both increase of germination energy index and intensification of plants growth and development processes. Treatment of seed by the «Radostim» contributed  the increase of the field seed germination on 2–4 %, and in variants with «Lignogumat of sodium» – on 5–6 %. Application in the ordered doses for the seed treatment contributed in the increase of the field seed germination on 7–9 % for «Gumifild» and on 10–15 % for «1R of Seedtreatment». In variants with «Radostim» absolutely dry mass of above-ground part of plants grew on 13,8–20,6 %, and mass of the root system – on 16–25 %. «Lignogumat» contributed in the increase of mass of above-ground part and root system accordingly on 17–19,5 % and 12,7–31 %. In variants with «Gumifild» growth of above-ground part was  on average 24,8 %, and root system – 26,3 %, and in the case of application of greater twice dose of «1R  Seedtreatment» – accordingly 37,5 and 40,6 %. On variants where mixture «Max Star 025 FS», 1,5 l/t + «Gumifild» 0,5 l/t was used on average fixed the increase of mass of above-ground part on 13,9 %,  root system – on 15,4 %, and on variants with mixture «Max Star 025 FS», 1,5 l/t + «1R» 1,0 l/t it was 25,6 and 26,2 % accordingly. We came to the conclusion about expedience of combining of mixtures pre-sowing seed treatment with the purpose of diminishing of the negative influencing of disinfectants on the indexes of germination energy and field seed germination of plants.


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 502f-502 ◽  
Author(s):  
Jack W. Buxton ◽  
Wenwei Jia ◽  
Guoqiang Hou

The automatic subirrigation system consists of a capillary mat placed above a constant water level in a reservoir. The optimum mat height above the water level was established by slanting a flat surface so the difference in vertical height from one end of the surface to the other was 25 cm. A ground cover providing water movement but not root penetration was placed over the mat. The capillary mat extended beyond the lowest end of the slopped surface and into the reservoir, the mat at the lowest end of the slopped surface was at the same vertical height as the water in the reservoir and remained constantly saturated. Plug trays were placed at intervals of 2.5 cm in vertical height above the water level. An average of 96-100% germination was obtained with marigold, tomato, impatiens and pepper seed in trays placed 5-7.5 cm in vertical height above the water level. These seedlings continued to develop and reached transplanting stage quicker than other trays. The rate and % germination was less in trays placed on the surface nearer to the height of the water in the reservoir. Germination in trays above 12.5 cm was greatly reduced and seed that did germinate did not develop and eventually died.


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