Root exudation and rhizoplane bacterial abundance of barley (Hordeum vulgare L.) in relation to nitrogen fertilization and root growth

1990 ◽  
Vol 127 (1) ◽  
pp. 81-89 ◽  
Author(s):  
E. Liljeroth ◽  
E. Bååth ◽  
I. Mathiasson ◽  
T. Lundborg

1972 ◽  
Vol 25 (4) ◽  
pp. 669 ◽  
Author(s):  
C Hackett ◽  
DA Rose

Previous papers have reported that relations between the total number, length, surface area, and volume of graminaceous root members tend to remain roughly constant during vegetative growth. Through the use of a model of the extension and branching of a seminal root of barley (Hordeum vulgare L.), which was developed for the purpose, an attempt has now been made to determine the properties of root growth responsible for the phenomenon.



1988 ◽  
Vol 68 (2) ◽  
pp. 425-432 ◽  
Author(s):  
Y. K. SOON

A field study was conducted in 1984 and 1985 to determine the spatial distribution with time of root length density of spring barley (Hordeum vulgare L.) growing in a Black Solod in northwestern Alberta. The weakly solonetzic Bnt horizon present in the solodic soil appeared not to inhibit root growth, and roots were present to 90 cm depth of soil. Drought in 1985 reduced root growth in general, and in particular in the surface soil (0 – 15 cm depth) between crop rows. Root growth in both years continued well after ear emergence and attained a maximum total length (14.5 and 9.5 km m−2 in 1984 and 1985, respectively) some time into grain-filling. Water uptake rates of up to 1.3 cm3 m−1 d−1 were observed; this maximum rate was associated with younger roots in the 60- to 90-cm depth in 1984. Low availability of subsoil water in 1985, however, resulted in low root density and water uptake rates in the 60- to 90-cm depth. The weighted mean uptake rate for the entire root system was slightly more than 0.4 cm3 m−1 d−1 in 1984 and about half that in 1985. Key words: Barley, Hordeum vulgare L., solonetzic soil, water inflow, root growth, root length density





1995 ◽  
Vol 73 (12) ◽  
pp. 1849-1858 ◽  
Author(s):  
B. E. Nichol ◽  
L. A. Oliveira

Aluminum-induced inhibition of root growth in the Al-sensitive cultivar Kearney of barley (Hordeum vulgare L.) is the result of disruption of both cell division in the meristematic region and cell expansion in the zone of elongation of the roots. In seedlings directly germinated in 50 μM Al, inhibition of root growth is detected 48 h after initiation of germination and it results primarily from the disruption of cell elongation. In seedlings germinated for 2 days under Al-free conditions, inhibition of root growth is apparent 8 h after transfer to 50 μM Al. In this instance, root growth inhibition is mainly the result of disruption of cell division in the meristematic region of the root. The calcium indicator dyes chlorotetracycline and Fluo-3 are used to study the distribution of intracellular calcium and its relationship to aluminum phototoxicity. Aluminum increases both chlorotetracycline and Fluo-3 fluorescence intensities. Fluorescence of the cytosolic calcium indicator dye Fluo-3 increases primarily in the zone of elongation of the roots of seedlings directly germinated in 50 μM aluminum. The increase in Fluo-3 fluorescence occurs concomitantly with major changes in both the length and width of the cells in the zone of elongation. The evidence suggests that changes in calcium homeostasis occurring in cells of the zone of elongation may be a major factor in the disruption of cell expansion and consequently root growth in seedlings directly germinated in 50 μM aluminum. Key words: aluminum, calcium, barley, chlorotetracycline, Fluo-3.





Agriculture ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 650
Author(s):  
Lisa Petzoldt ◽  
Miriam Athmann ◽  
Andreas Buechse ◽  
Timo Kautz

Biopores provide nutrients from root debris and earthworm casts. Inside large biopores, root function is limited due to the lack of root–soil contact. However, the immediate surroundings of biopores may hold a key function as “hotspots” for root growth in the subsoil. To date, sufficient quantitative information on the distribution of roots and nutrients around biopores is missing. In this field study, the biopore sheath was sampled at distances of 0–2, 2–4, 4–8, and 8–12 mm from the surface of the pore wall. The results show a laterally decreasing gradient from the pore towards 8–12 mm distance in root length density (RLD) of spring barley (Hordeum vulgare L.) and faba bean (Vicia faba L.), as well as in total nitrogen (Nt)- and total carbon (Ct)-content. In the biopore sheath (2–12 mm), the share of roots with a diameter of less than 0.4 mm was 92% for barley and 89% for faba bean. The findings support the view that roots can utilize biopores to gain access to deeper soil layers and may use the sheath for nutrient uptake and entrance through to the bulk soil. However, especially for barley, the inner layer of the biopore sheath appeared to be more important for root growth than the sheath of farer distance.



Sign in / Sign up

Export Citation Format

Share Document