Dynamics of root growth stimulation in Nicotiana tabacum in increasing light intensity

2006 ◽  
Vol 29 (10) ◽  
pp. 1936-1945 ◽  
Author(s):  
KERSTIN A. NAGEL ◽  
ULRICH SCHURR ◽  
ACHIM WALTER
Author(s):  
Maria Theresia Sri Budiastuti ◽  
Djoko Purnomo ◽  
Supriyono Supriyono ◽  
Bambang Pujiasmanto ◽  
Desy Setyaningrum

<p class="Default"><em>Indigofera tinctoria</em> is a legume that is cultivated as a source of natural indigo dyes. As a legume, <em>Indigofera tinctoria</em> is capable of symbiosis with soil microbes. This study evaluates the effects of light intensity and microbial inoculation on root growth and nodulation. The study used a complete randomized block design with a split-plot pattern. Light intensity was the main plot with four levels of light intensity 100%, 50%, 25%, and 10%. Microbial inoculation was a subplot with four levels without inoculation, mycorrhizae inoculation, rhizobium inoculation, and double inoculation with both mycorrhizae and rhizobium. The results obtained show that light intensity and microbial inoculation affected root length, root fresh weight, root biomass, and the number of nodules. 50% light intensity was optimum for root length, while 100% light intensity was optimum for root fresh weight, root biomass, and a number of nodules. Root growth and nodulation were further increased with double inoculation. The combination of light intensity and microbial inoculation affected root biomass and nodulation. The combination of 100% light intensity and double inoculation resulted in the highest root biomass and nodule numbers. Mycorrhizae and rhizobium have a synergistic relationship to nodulation and root growth. Double inoculation with mycorrhizae and rhizobium efficiently increased root biomass and the number of nodules under low or high light intensity.</p>


2019 ◽  
Vol 14 (1) ◽  
pp. 349-357 ◽  
Author(s):  
Shubin Li ◽  
Lili Zhou ◽  
Sipan Wu ◽  
Li Liu ◽  
Meng Huang ◽  
...  

AbstractThis study examines the effects of light emitting diodes (LEDs) on tissue culture proliferation of Acacia melanoxylon plantlets among five different clones (FM1, FM2, FM4, FM5, and FM10). Shoot bud apex cuttings were transplanted onto Murashige and Skoog basal medium containing 0.1 mg L-1 6-benzyladenine and 0.5 mg L-1 naphthalene acetic acid and cultured in vitro for 40 days. Root growth was studied under different light intensities and photoperiods ex vitro. The bud proliferation coefficient was greatest under a light intensity of 45 μmol m-2 s-1 photosynthetic photon flux and photoperiod of 16 h light, but decreased as the light intensity increased. However, the greatest light intensity was beneficial for the growth of robust plantlets. Plantlets exposed to red and blue LED combinations grew tall and green, with a small number of roots. Plantlets also grew taller and some roots expanded under the longer photoperiod. Increased light intensity had positive effects on root number and rooting rate, and prolonged light greatly increased root number. Therefore, lower light intensity and a short photoperiod were beneficial for bud proliferation, while red/blue LED combinations, increased light intensity, and longer light illumination were beneficial for plantlet growth and root growth of Acacia melanoxylon.


1975 ◽  
Vol 2 (3) ◽  
pp. 425 ◽  
Author(s):  
L Rahman ◽  
D Aspinall ◽  
LG Paleg

The influences of light intensity, rooting medium, and the excision of various organs on the early phases of root growth in barley seedlings (cv. Piroline) were explored. The emergence of root axes was affected by light intensity and excision of roots, endosperm or shoot, but was not altered by the rooring medium. Elongation of the emerged axes was similarly responsive. The elongation rate of both the set of axes and individual axes fell wi4h time. The elongation rate of laterals was less than that of the axes and was sensitive to the excision of seedling organs. The data are discussed in relation to the hypothesis that the growth of the root system is determined by the availability of substrate.


1999 ◽  
Vol 45 (4) ◽  
pp. 339-342 ◽  
Author(s):  
Colette Jacoud ◽  
Dominique Job ◽  
Patrick Wadoux ◽  
René Bally

Maize seeds were inoculated with a commercial inoculant containing 1.3 × 107 Azospirillum lipoferum CRT1 cells. After 24 or 48 h, bacteria were washed from the seed surface. Washed and unwashed seeds were then planted in pots containing perlite and grown for 28 days under greenhouse conditions. Whatever the density of Azospirillum at planting, the number of these bacteria at the end of the experiment was similar (1.9-8.0 × 107 bacteria·plant-1). However, comparison of root surface areas of the plants were different depending on the period of contact between seeds and the density of the inoculum. Twenty-four hours of contact was not sufficient to increase root growth surface areas. Contact for 48 h permitted us to obtain root surface areas comparable with those measured after a continuous contact. These results showed that in order to promote maize root surface areas, an optimal density of Azospirillum is not required during the whole cultural cycle. This optimal density is indispensable only up to the emergence of the radicle.Key words: Azospirillum, maize, inoculation, PGPR.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yohanna Evelyn Miotto ◽  
Cibele Tesser da Costa ◽  
Remko Offringa ◽  
Jürgen Kleine-Vehn ◽  
Felipe dos Santos Maraschin

Plant development is highly affected by light quality, direction, and intensity. Under natural growth conditions, shoots are directly exposed to light whereas roots develop underground shielded from direct illumination. The photomorphogenic development strongly represses shoot elongation whereas promotes root growth. Over the years, several studies helped the elucidation of signaling elements that coordinate light perception and underlying developmental outputs. Light exposure of the shoots has diverse effects on main root growth and lateral root (LR) formation. In this study, we evaluated the phenotypic root responses of wild-type Arabidopsis plants, as well as several mutants, grown in a D-Root system. We observed that sucrose and light act synergistically to promote root growth and that sucrose alone cannot overcome the light requirement for root growth. We also have shown that roots respond to the light intensity applied to the shoot by changes in primary and LR development. Loss-of-function mutants for several root light-response genes display varying phenotypes according to the light intensity to which shoots are exposed. Low light intensity strongly impaired LR development for most genotypes. Only vid-27 and pils4 mutants showed higher LR density at 40 μmol m–2 s–1 than at 80 μmol m–2 s–1 whereas yuc3 and shy2-2 presented no LR development in any light condition, reinforcing the importance of auxin signaling in light-dependent root development. Our results support the use of D-Root systems to avoid the effects of direct root illumination that might lead to artifacts and unnatural phenotypic outputs.


Author(s):  
Z. M. Kuramshina ◽  
R. M. Khairullin ◽  
Yu. V. Smirnova

In this study, we tested the effect of two strains of bacteria B. subtilis 26D and 11ВМ on three varieties of wheat Triticum aestivum L.: Omskaya 35, Kazakhstanskaya 10 (spring), Volzhskaya qualitative (winter).The peculiarity of the plants response to endophytic inoculation depended on the strain of the microorganism, the concentration of cells in the preparation, and the variety of wheat during the experiment in Petri dishes. Both strains showed a strong growth-stimulating effect when seed was inoculated with suspensions of bacteria with a concentration of 106 cells/ml. There was no effect when seed cells were inoculated with bacteria at a concentration of 109 cells / ml. Plants varieties Omskaya 35 were most responsive to inoculation with endophytes. The variety was well responsive to the inoculation of bacteria cells at different concentrations. The variety Volzhskaya quality had the least growth stimulation. Plants of this variety responded well when grown in soil, unlike experiments in Petri dishes. The variety Kazakhstanskaya 10 was less responsive when growing plants in Petri dishes. There was no difference between the size of the shoots of inoculated and non-inoculated plants of the variety Kazakh 10, only stimulation of root growth was observed. It was concluded that there is a pronounced responsiveness of wheat varieties to the effect of endophytic strains of bacteria B. subtilis 26D the basis of biofungicide (Fitosporin-M) and this must be considered when using biofungicide for wheat cultivation.


2019 ◽  
Vol 70 (15) ◽  
pp. 3955-3967 ◽  
Author(s):  
Kelly Chapman ◽  
Michael Taleski ◽  
Huw A Ogilvie ◽  
Nijat Imin ◽  
Michael A Djordjevic

AbstractLateral root (LR) proliferation is a major determinant of soil nutrient uptake. How resource allocation controls the extent of LR growth remains unresolved. We used genetic, physiological, transcriptomic, and grafting approaches to define a role for C-TERMINALLY ENCODED PEPTIDE RECEPTOR 1 (CEPR1) in controlling sucrose-dependent LR growth. CEPR1 inhibited LR growth in response to applied sucrose, other metabolizable sugars, and elevated light intensity. Pathways through CEPR1 restricted LR growth by reducing LR meristem size and the length of mature LR cells. RNA-sequencing of wild-type (WT) and cepr1-1 roots with or without sucrose treatment revealed an intersection of CEP–CEPR1 signalling with the sucrose transcriptional response. Sucrose up-regulated several CEP genes, supporting a specific role for CEP–CEPR1 in the response to sucrose. Moreover, genes with basally perturbed expression in cepr1-1 overlap with WT sucrose-responsive genes significantly. We found that exogenous CEP inhibited LR growth via CEPR1 by reducing LR meristem size and mature cell length. This result is consistent with CEP–CEPR1 acting to curtail the extent of sucrose-dependent LR growth. Reciprocal grafting indicates that LR growth inhibition requires CEPR1 in both the roots and shoots. Our results reveal a new role for CEP–CEPR1 signalling in controlling LR growth in response to sucrose.


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