Seed germination, root elongation, root-tip mitosis, and micronucleus induction of five crop plants exposed to chromium in fluvo-aquic soil

2014 ◽  
Vol 33 (3) ◽  
pp. 671-676 ◽  
Author(s):  
Jing- Hou ◽  
Guan-Nan Liu ◽  
Wei Xue ◽  
Wen-Jun Fu ◽  
Bao-Cui Liang ◽  
...  
Keyword(s):  
Seed Germination ◽  
Root Elongation ◽  
Crop Plants ◽  
Root Tip ◽  
Micronucleus Induction

scholarly journals Membrane Sterol Composition in Arabidopsis thaliana Affects Root Elongation via Auxin Biosynthesis

2021 ◽  
Vol 22 (1) ◽  
pp. 437
Author(s):  
Meng Wang ◽  
Panpan Li ◽  
Yao Ma ◽  
Xiang Nie ◽  
Markus Grebe ◽  
...  
Keyword(s):  
Root Elongation ◽  
Auxin Transport ◽  
Sterol Composition ◽  
Polar Auxin Transport ◽  
Sterol Biosynthesis ◽  
Auxin Biosynthesis ◽  
Root Tip ◽  
Auxin Signaling ◽  
Auxin Response ◽  
Short Root

Plant membrane sterol composition has been reported to affect growth and gravitropism via polar auxin transport and auxin signaling. However, as to whether sterols influence auxin biosynthesis has received little attention. Here, by using the sterol biosynthesis mutant cyclopropylsterol isomerase1-1 (cpi1-1) and sterol application, we reveal that cycloeucalenol, a CPI1 substrate, and sitosterol, an end-product of sterol biosynthesis, antagonistically affect auxin biosynthesis. The short root phenotype of cpi1-1 was associated with a markedly enhanced auxin response in the root tip. Both were neither suppressed by mutations in polar auxin transport (PAT) proteins nor by treatment with a PAT inhibitor and responded to an auxin signaling inhibitor. However, expression of several auxin biosynthesis genes TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS1 (TAA1) was upregulated in cpi1-1. Functionally, TAA1 mutation reduced the auxin response in cpi1-1 and partially rescued its short root phenotype. In support of this genetic evidence, application of cycloeucalenol upregulated expression of the auxin responsive reporter DR5:GUS (β-glucuronidase) and of several auxin biosynthesis genes, while sitosterol repressed their expression. Hence, our combined genetic, pharmacological, and sterol application studies reveal a hitherto unexplored sterol-dependent modulation of auxin biosynthesis during Arabidopsis root elongation.

Effects of root zone temperature on root initiation and elongation in red pine seedlings

1986 ◽  
Vol 16 (4) ◽  
pp. 696-700 ◽  
Author(s):  
Chris P. Andersen ◽  
Edward I. Sucoff ◽  
Robert K. Dixon
Keyword(s):  
Root Elongation ◽  
Root Zone ◽  
Soluble Sugar ◽  
Soluble Sugars ◽  
Red Pine ◽  
Root Tip ◽  
Root Initiation ◽  
Root Zone Temperature ◽  
Pine Seedlings ◽  
Zone Temperature

The influence of root zone temperature on root initiation, root elongation, and soluble sugars in roots and shoots was investigated in a glasshouse using 2-0 red pine (Pinusresinosa Ait.) seedlings lifted from a northern Minnesota nursery. Seedlings were potted in a sandy loam soil and grown in chambers where root systems were maintained at 8, 12, 16, or 20 °C for 27 days; seedling shoots were exposed to ambient glasshouse conditions. Total new root length was positively correlated with soil temperature 14, 20, and 27 days after planting, with significantly more new root growth at 20 °C than at other temperatures. The greatest number of new roots occurred at 16 °C; the least, at 8 °C. Total soluble sugar concentrations in stem tissue decreased slightly as root temperature increased. Sugar concentrations in roots were similar at all temperatures. The results suggest that root elongation is suppressed more than root tip formation when red pine seedlings are exposed to the cool soil temperatures typically found during spring and fall outplanting.

Identification and characterization of novel QTL conferring internal detoxification of aluminum in soybean

2021 ◽  
Author(s):  
Yang Li ◽  
Heng Ye ◽  
Li Song ◽  
Tri D Vuong ◽  
Qijian Song ◽  
...  
Keyword(s):  
Root Length ◽  
Root Elongation ◽  
Primary Root ◽  
Pedigree Analysis ◽  
Length Ratio ◽  
Root Tip ◽  
Root Initiation ◽  
Al Tolerance ◽  
Al Stress ◽  
Root Length Ratio

Abstract Aluminum (Al) toxicity inhibits soybean root growth, leading to insufficient water and nutrient uptake. In this research, two soybean lines (Magellan and PI 567731) were identified differing in Al tolerance as determined by primary root length ratio (PRL_Ratio), total root length ratio (TRL_Ratio), and root tip number ratio (RTN_Ratio) under Al stress compared to unstressed controlled conditions. Serious root necrosis was observed in PI 567731, but not in Magellan under Al stress. An F8 recombinant inbred line population derived from a cross between Magellan and PI 567731 was used to map the quantitative trait loci (QTL) for Al-tolerance. Three QTL on chromosomes 3, 13, and 20, with tolerant-alleles from Magellan, were identified. qAl_Gm13 and qAl_Gm20, explained large phenotypic variations (13-27%) and played roles in maintaining root elongation. qAl_Gm03 was involved in maintaining root initiation under Al stress. These results suggested the importance of using the parameters of root elongation and root initiation in Al tolerance studies. In addition, qAl_Gm13 and qAl_Gm20 were confirmed in near-isogenic backgrounds and were identified to epistatically regulate Al tolerance in internal detoxification instead of Al 3+ exclusion. The candidate genes for qAl_Gm13 and qAl_Gm20 were suggested by analyzing a previous RNA-seq study. Phylogenetic and pedigree analysis identified the tolerant alleles of both loci derived from the US ancestor line, A.K.[FC30761], originally from China. Our results provide novel genetic resources for breeding Al-tolerant soybeans and suggest that the internal detoxification contributes to soybean tolerance to excessive soil Al.

scholarly journals Multiwalled carbon nanotubes in alfalfa and wheat: toxicology and uptake

2012 ◽  
Vol 9 (77) ◽  
pp. 3514-3527 ◽  
Author(s):  
Pola Miralles ◽  
Errin Johnson ◽  
Tamara L. Church ◽  
Andrew T. Harris
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Root Elongation ◽  
Wheat Root ◽  
Root Tip ◽  
Multiwalled Carbon ◽  
Wheat Seedlings ◽  
Industrial Grade ◽  
High Concentrations ◽  
Multiwalled Cnts

Data on the bioavailability and toxicity of carbon nanotubes (CNTs) in the environment, and, in particular, on their interactions with vascular plants, are limited. We investigated the effects of industrial-grade multiwalled CNTs (75 wt% CNTs) and their impurities on alfalfa and wheat. Phytotoxicity assays were performed during both seed germination and seedling growth. The germinations of both species were tolerant of up to 2560 mg l −1 CNTs, and root elongation was enhanced in alfalfa and wheat seedlings exposed to CNTs. Remarkably, catalyst impurities also enhanced root elongation in alfalfa seedlings as well as wheat germination. Thus the impurities, not solely the CNTs, impacted the plants. CNT internalization by plants was investigated using electron microscopy and two-dimensional Raman mapping. The latter showed that CNTs were adsorbed onto the root surfaces of alfalfa and wheat without significant uptake or translocation. Electron microscopy investigations of internalization were inconclusive owing to poor contrast, so Fe 3 O 4 -functionalized CNTs were prepared and studied using energy-filter mapping of Fe 3 O 4 . CNTs bearing Fe 3 O 4 nanoparticles were detected in the epidermis of one wheat root tip only, suggesting that internalization was possible but unusual. Thus, alfalfa and wheat tolerated high concentrations of industrial-grade multiwalled CNTs, which adsorbed onto their roots but were rarely taken up.

scholarly journals Root elongation, water stress, and mechanical impedance: a review of limiting stresses and beneficial root tip traits

2011 ◽  
Vol 62 (1) ◽  
pp. 59-68 ◽  
Author(s):  
A. Glyn Bengough ◽  
B. M. McKenzie ◽  
P. D. Hallett ◽  
T. A. Valentine
Keyword(s):  
Water Stress ◽  
Root Elongation ◽  
Mechanical Impedance ◽  
Root Tip

scholarly journals Effects of ZnO nanoparticles in alfalfa, tomato, and cucumber at the germination stage: Root development and X-ray absorption spectroscopy studies

2013 ◽  
Vol 85 (12) ◽  
pp. 2161-2174 ◽  
Author(s):  
Guadalupe de la Rosa ◽  
Martha Laura López-Moreno ◽  
David de Haro ◽  
Cristian E. Botez ◽  
José R. Peralta-Videa ◽  
...  
Keyword(s):  
Seed Germination ◽  
Absorption Spectroscopy ◽  
Root Elongation ◽  
Dry Weight ◽  
Zno Nps ◽  
X Ray ◽  
Zn Content ◽  
Spectroscopy Studies ◽  
X Ray Absorption ◽  
Germination Stage

Past reports indicate that some nanoparticles (NPs) affect seed germination; however, the biotransformation of metal NPs is still not well understood. This study investigated the toxicity on seed germination/root elongation and the uptake of ZnO NPs and Zn2+ in alfalfa (Medicago sativa), cucumber (Cucumis sativus), and tomato (Solanum lycopersicum) seedlings. Seeds were treated with ZnO NPs at 0–1600 mg L–1 as well as 0–250 mg L–1 Zn2+ for comparison purposes. Results showed that at 1600 mg L–1 ZnO NPs, germination in cucumber increased by 10 %, and alfalfa and tomato germination were reduced by 40 and 20 %, respectively. At 250 mg Zn2+ L–1, only tomato germination was reduced with respect to controls. The highest Zn content was of 4700 and 3500 mg kg–1 dry weight (DW), for alfalfa seedlings germinated in 1600 mg L–1 ZnO NPs and 250 mg L–1 Zn2+, respectively. Bulk X-ray absorption spectroscopy (XAS) results indicated that ZnO NPs were probably biotransformed by plants. The edge energy positions of NP-treated samples were at the same position as Zn(NO3)2, which indicated that Zn in all plant species was as Zn(II).

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