scholarly journals Mycorrhizal Influence on Transpiration Rates of Detached Leaves of Cowpea, Rose, and Geranium Exposed to Varying Levels of Abscisic Acid (ABA), pH, Calcium, and Phosphorus

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 647e-647
Author(s):  
Craig D. Green ◽  
Ann Stodola ◽  
Robert M. Augé

Mycorrhizal colonization can alter stomatal behavior of host leaves during drought. This may be related to an altered production or reception of a chemical signal of soil drying. We tested whether intact root systems were required to observe a mycorrhizal effect on leaf transpiration (E), or whether some residual mycorrhizal influence on leaves could affect E of foliage detached from root systems. Transpiration assays were performed in the presence of several possible candidates for a chemical signal of soil drying. In detached leaves of Vigna unguiculata (cowpea), colonization interacted significantly with ABA and pH in regulating transpiration. Colonization affected E of detached Rosa hybrida (rose) leaves but had no effect on E of detached leaves of Pelargonium hortorum (geranium). In each species tested, increasing the ABA concentration decreased E. In cowpea, calcium appeared to alter stomatal sensitivity to ABA, as well as regulate stomatal activity directly. The pH of the feeding solution affected E in rose, but did not change E independently in cowpea or geranium. Adding phosphorus to the feeding solution did not alter E or the apparent sensitivity of stomata to ABA in any of the test species. Colonization of roots by mycorrhizal fungi can result in residual effects in detached leaves, that can alter the stomatal reception of chemical signals in both rose and cowpea.

2013 ◽  
Vol 41 (2) ◽  
pp. 524 ◽  
Author(s):  
Qiu-Dan NI ◽  
Ying-Ning ZOU ◽  
Qiang-Sheng WU ◽  
Yong-Ming HUANG

Arbuscular mycorrhizal fungi (AMF) can enhance tolerance of plants to soil water deficit, whereas morphological observations of reactive oxygen species and antioxidant enzyme system are poorly studied. The present study thereby evaluated temporal variations of the antioxidant enzyme system in citrus (Citrus tangerina) seedlings colonized by Glomus etunicatum and G. mosseae over a 12-day period of soil drying. Root colonization by G. etunicatum and G. mosseae decreased with soil drying days from 32.0 to 1.0% and 50.1 to 4.5% in 0-day to 12-day, respectively. Compared to the non-AM controls, the AMF colonized plants had significantly lower tissue (both leaves and roots) hydrogen peroxide (H2O2) and superoxide anion radical (O2•–) concentrations during soil water deficit, whereas 1.03–1.92, 1.25–1.84 and 1.18–1.69 times higher enzyme activity in superoxide dismutase, peroxidase (POD) and catalase. In situ leaf H2O2 and root POD location also showed that AM seedlings had less leaf H2O2 but higher root POD accumulation. Furthermore, significantly higher root infection and antioxidant enzymatic activities in plants colonized with G. mosseae expressed than with G. etunicatum during the soil drying. These results demonstrated that the AMs could confer greater tolerance of citrus seedlings to soil water deficit through an enhancement in their antioxidant enzyme defence system whilst an decrease level in H2O2 and O2•–.


1998 ◽  
Vol 28 (1) ◽  
pp. 150-153
Author(s):  
J N Gemma ◽  
R E Koske ◽  
E M Roberts ◽  
S Hester

Rooted cuttings of Taxus times media var. densiformis Rehd. were inoculated with the arbuscular mycorrhizal fungi Gigaspora gigantea (Nicol. & Gerd.) Gerd. & Trappe or Glomus intraradices Schenck and Smith and grown for 9-15 months in a greenhouse. At the completion of the experiments, leaves of inoculated plants contained significantly more chlorophyll (1.3-4.1 times as much) than did noninoculated plants. In addition, mycorrhizal plants had root systems that were significantly larger (1.3-1.4 times) and longer (1.7-2.1 times) than nonmycorrhizal plants, and they possessed significantly more branch roots (1.3-2.9 times). No differences in stem diameter and height or shoot dry weight were evident at the end of the experiments, although the number of buds was significantly greater in the cuttings inoculated with G. intraradices after 15 months.


1997 ◽  
Vol 75 (11) ◽  
pp. 1903-1912 ◽  
Author(s):  
Kyeong W. Yun ◽  
M. A. Maun

Greenhouse studies were conducted to test allelopathic effects of Artemisia campestris ssp. caudata on seed germination and seedling growth of several sand-dune species and colonization by mycorrhizal fungi. The aqueous extracts of A. campestris showed no inhibitory effect on seed germination, seedling elongation, or dry-weight growth of plants at lower concentrations (10 and 50%), but 100% concentration of the extracts caused varying degrees of inhibition depending on the test species. The mixing of dry leaves of seedlings of A. campestris to the sand showed severe inhibition of Elymus canadensis seedlings. The percent germination of test species in soil from the rhizosphere of A. campestris was significantly lower than that of the control. The leaf area and dry weight were also lower but the differences were not significant. The aqueous extract inhibited mycorrhizal fungal colonization in roots of three sand-dune grasses. Key words: allelopathy, Artemisia campestris ssp. caudata, seed germination, seedling growth, mycorrhizal fungi.


CONVERSAZIONES were held this year on 9 May and 27 June. At the first conversazione twenty-seven exhibits and two films were shown. The fine structure of plant roots in relation to transport of nutrient ions and water was demonstrated by Dr D. T. Clarkson of the A.R.C. Letcombe Laboratory, Wantage and Dr A. W. Robards of the Department of Biology, University of York. Two major pathways by which nutrients and water move radially across the cortex towards the central vascular tissue have been distinguished by the use of tracer studies of adsorption by different zones of intact root systems, microautoradiography and electron microscopy. Movement can be apoplastic through cell walls, or symplastic between cells joined by plasmodesmata. As the root ages, structural changes in the endodermis reduce movement in the former pathway but the symplast is not interrupted by the elaboration of endodermal walls because plasmodesmatal connexions remain intact. These observations help explain the contrasting extent to which different ions and water reach the shoot from young and mature parts of root systems.


Author(s):  
Ya. S. Kamelchuk ◽  
O. Yu. Baranov ◽  
P. S. Kiryanov ◽  
V. E. Padutov

A metagenomic analysis of the endophytic microflora of Vaccinium corymbosum L. and Vaccinium myrtillus L. root systems was carried out. Two dominant species of micromycetes forming ericoid mycorrhiza were identified - Phialocephala fortinii C. J. K. Wang & H. E. Wilcox and Pezicula sp. Tul. & C. Tul. Pure cultures of mycorrhizal fungi were prepared, a comprehensive morphological and genetic assay of the strains was carried out. Based on the results of genetic-taxonomic analysis, the assumption of the polyphyletic origin of species belonging to Phialocephala and Pezicula is confirmed.


2002 ◽  
Vol 68 (7) ◽  
pp. 3639-3643 ◽  
Author(s):  
Xuan Guo ◽  
Marc W. van Iersel ◽  
Jinru Chen ◽  
Robert E. Brackett ◽  
Larry R. Beuchat

ABSTRACT The possibility of uptake of salmonellae by roots of hydroponically grown tomato plants was investigated. Within 1 day of exposure of plant roots to Hoagland nutrient solution containing 4.46 to 4.65 log10 CFU of salmonellae/ml, the sizes of the pathogen populations were 3.01 CFU/g of hypocotyls and cotyledons and 3.40 log10 CFU/g of stems for plants with intact root systems (control) and 2.55 log10 CFU/g of hypocotyls and cotyledons for plants from which portions of the roots had been removed. A population of ≥3.38 log10 CFU/g of hypocotyls-cotyledons, stems, and leaves of plants grown for 9 days was detected regardless of the root condition. Additional studies need to be done to unequivocally demonstrate that salmonellae can exist as endophytes in tomato plants grown under conditions that simulate commonly used agronomic practices.


Sign in / Sign up

Export Citation Format

Share Document