Inhibition by mevinolin of mevalonate formation and plant root elongation

1982 ◽  
Vol 69 (5) ◽  
pp. 242-243 ◽  
Author(s):  
T. J. Bach ◽  
H. K. Lichtenthaler
Keyword(s):  
Root Elongation ◽  
Plant Root ◽  
Plant Root Elongation

Histological and Cytological Effects of Haloxyfop on Sorghum (Sorghum bicolor) and Unicorn-Plant (Proboscidea louisianica) Root Meristems

Weed Science ◽  
1989 ◽  
Vol 37 (4) ◽  
pp. 503-511 ◽  
Author(s):  
Steven F. Vaughn ◽  
Morris G. Merkle
Keyword(s):  
Sorghum Bicolor ◽  
Mitotic Index ◽  
Cell Walls ◽  
Root Elongation ◽  
Plant Root ◽  
Root Apex ◽  
Plant Roots ◽  
Apical Region ◽  
Primary Roots ◽  
Plant Root Elongation

The effects of haloxyfop on elongation, mitotic index, and morphology of sorghum and unicorn-plant primary roots were examined. Elongation of sorghum roots was completely inhibited by haloxyfop concentrations of 10–6M or greater 24 h after treatment, whereas unicorn-plant root elongation was unaffected by the same concentrations 72 h after treatment. Mitotic indices of sorghum roots were reduced by both 10–6and 10–8M haloxyfop, with the higher concentration reducing the index to near zero by 24 h of exposure. The mitotic indices of unicorn-plant roots were unaffected by the same levels of the herbicide after both 24- and 48-h treatment. Histological analyses showed that after 24 h exposure to 10–6M haloxyfop, large vacuoles were present in cells at the root apex that normally did not exhibit these organelles. After 48 h of exposure many cells in the apical region appeared to lack visible cytoplasm and/or nuclei, and by 72 h only cell walls remained visibly evident, and many cells had collapsed. These changes are similar to those that occur in tissues undergoing senescence. Treatment of sorghum roots with 10–8M haloxyfop did not cause discernible changes after 72 h. Unicorn-plant roots treated with 10–6M haloxyfop appeared unaffected after 72 h.

Radial oxygen loss and physical barriers in relation to root tissue age in species with different types of aerenchyma

2015 ◽  
Vol 42 (1) ◽  
pp. 9 ◽  
Author(s):  
Milena E. Manzur ◽  
Agustín A. Grimoldi ◽  
Pedro Insausti ◽  
Gustavo G. Striker
Keyword(s):  
Root Elongation ◽  
Root Zone ◽  
Plant Root ◽  
Root Tissue ◽  
Radial Oxygen Loss ◽  
Outer Cortex ◽  
Aerenchyma Formation ◽  
Oxygen Loss ◽  
Hypoxic Conditions ◽  
Apoplastic Barriers

Plant root aeration relies on aerenchyma and barrier formation in outer cortex influencing the radial oxygen loss (ROL) from roots towards the rhizosphere. Plant species display large variation in strategies for both responses. We investigated the impacts of root-zone hypoxia on aerenchyma formation and development of ROL apoplastic barriers in the outer cortex as a function of root tissue age using three lowland grassland species, each with alternative aerenchyma structure. All species increased root aerenchyma and continued with root elongation after imposing hypoxia. However, ROL barrier development differed: (i) Rumex crispus L. displayed only ‘partial’ barrier to ROL evidenced at older tissue ages, (ii) Cyperus eragrostis Lam. initiated a ‘tighter’ barrier to ROL following exposure to hypoxia in tissues older than 3 days, and (iii) Paspalidium geminatum (Forssk.) Stapf demonstrated highly effective inhibition of ROL under aerated and hypoxic conditions at all tissue ages related to constitutive ‘tight’ apoplastic barriers in outer cortex. Thus, hypoxic conditions affected root elongation and ‘tightness’ of apoplastic barriers depending on species. The physiological implications of the different ROL responses among species in relation to the differential formation of barriers are discussed.

Response of the plant root to aluminum stress: Analysis of the inhibition of the root elongation and changes in membrane function

1996 ◽  
Vol 109 (1) ◽  
pp. 99-105 ◽  
Author(s):  
Hideaki Matsumoto ◽  
Yasushi Senoo ◽  
Minobu Kasai ◽  
Masayoshi Maeshima
Keyword(s):  
Stress Analysis ◽  
Root Elongation ◽  
Plant Root ◽  
Aluminum Stress ◽  
Membrane Function

scholarly journals AtMYB44 Positively Regulates the Enhanced Elongation of Primary Roots Induced by N-3-Oxo-Hexanoyl-Homoserine Lactone in Arabidopsis thaliana

2016 ◽  
Vol 29 (10) ◽  
pp. 774-785 ◽  
Author(s):  
Qian Zhao ◽  
Man Li ◽  
Zhenhua Jia ◽  
Fang Liu ◽  
Hong Ma ◽  
...  
Keyword(s):  
Root Growth ◽  
Root Elongation ◽  
Plant Root ◽  
Primary Root ◽  
Homoserine Lactone ◽  
Defense Responses ◽  
Plant Response ◽  
Signal Molecules ◽  
Cellular Analysis ◽  
Primary Root Growth

N-acyl-homoserine lactones (AHL) are the quorum-sensing (QS) signal molecules used by many gram-negative bacteria to coordinate their collective behavior in a population. Recent evidence demonstrates their roles in plant root growth and defense responses. AtMYB44 is a multifaceted transcriptional factor that functions in many physiological processes in plants but whether AtMYB44 modulates the plant response to AHL with aspects of primary root elongation remains unknown. Here, we show that the expression of AtMYB44 was upregulated upon treatment with N-3-oxo-hexanoyl-homoserine lactone (3OC6-HSL). The stimulatory effect of 3OC6-HSL on primary root elongation was abolished in the AtMYB44 functional-deficiency mutant atmby44. In contrast, an enhanced promoting-impact of 3OC6-HSL on primary root growth was observed in AtMYB44-overexpressing plant MYB44OTA. Cellular analysis indicated that the prolonged primary root elicited by 3OC6-HSL is the consequence of increased cell division in the meristem zone and enhanced cell elongation in the elongation zone, and AtMYB44 may act as a positive regulator in this process. Furthermore, we demonstrated that AtMYB44 might participate in the 3OC6-HSL-mediated primary root growth via regulating the expression of cytokinin- and auxin-related genes. The data establish a genetic connection between the regulatory role of AtMYB44 in phytohormones-related gene expression and plant response to the bacterial QS signal.

Strategies used by rhizobia to lower plant ethylene levels and increase nodulation

2002 ◽  
Vol 48 (11) ◽  
pp. 947-954 ◽  
Author(s):  
Wenbo Ma ◽  
Donna M Penrose ◽  
Bernard R Glick
Keyword(s):  
Plant Root ◽  
Molecular Nitrogen ◽  
Acc Deaminase ◽  
Inhibitory Effect ◽  
Symbiotic Association ◽  
Fixed Nitrogen ◽  
Negative Factor ◽  
Negative Effect ◽  
Plant Root Elongation ◽  
Lower Plant

Agriculture depends heavily on biologically fixed nitrogen from the symbiotic association between rhizobia and plants. Molecular nitrogen is fixed by differentiated forms of rhizobia in nodules located on plant roots. The phytohormone, ethylene, acts as a negative factor in the nodulation process. Recent discoveries suggest several strategies used by rhizobia to reduce the amount of ethylene synthesized by their legume symbionts, decreasing the negative effect of ethylene on nodulation. At least one strain of rhizobia produces rhizobitoxine, an inhibitor of ethylene synthesis. Active 1-aminocyclopropane-1-carboxylate (ACC) deaminase has been detected in a number of other rhizobial strains. This enzyme catalyzes the cleavage of ACC to α-ketobutyrate and ammonia. It has been shown that the inhibitory effect of ethylene on plant root elongation can be reduced by the activity of ACC deaminase.Key words: rhizobia, nodulation, ethylene, ACC deaminase, rhizobitoxine.

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