Whole-plant frost hardiness of mycorrhizal (Hebeloma sp. or Suillus luteus) and non-mycorrhizal Scots pine seedlings

2018 ◽  
Vol 39 (6) ◽  
pp. 951-960 ◽  
Author(s):  
Anna Korhonen ◽  
Tarja Lehto ◽  
Jaakko Heinonen ◽  
Tapani Repo

Abstract Ectomycorrhizal trees are common in the cold regions of the world, yet the role of the mycorrhizal symbiosis in plant cold tolerance is poorly known. Moreover, the standard methods for testing plant frost hardiness may not be adequate for roots and mycorrhizas. The aims of this study were to compare the frost hardiness of mycorrhizal and non-mycorrhizal Scots pine (Pinus sylvestris L.) seedlings and to test the use of reverse-flow root hydraulic conductance (Kr) measurement for root frost hardiness determination. Mycorrhizal (Hebeloma sp. or Suillus luteus) and non-mycorrhizal seedlings were grown in controlled-environment chambers for 13 weeks. After this, half of the plants were allotted to a non-hardening treatment (long day and high temperature, same as during the preceding growing season) and the other half to a hardening (short day and low temperature) ‘autumn’ treatment for 4 weeks. The intact seedlings were exposed to whole-plant freezing tests and the needle frost hardiness was measured by relative electrolyte leakage (REL) method. The seedlings were grown for three more weeks for visual damage assessment and Kr measurements using a high-pressure flow meter (HPFM). Mycorrhizas did not affect the frost hardiness of seedlings in either hardening treatment. The effect of the hardening treatment on frost hardiness was shown by REL and visual assessment of the aboveground parts as well as Kr of roots. Non-mycorrhizal plants were larger than mycorrhizal ones while nitrogen and phosphorus contents (per unit dry mass) were similar in all mycorrhiza treatments. In plants with no frost exposure, the non-mycorrhizal treatment had higher Kr. There was no mycorrhizal effect on plant frost hardiness when nutritional effects were excluded. Further studies are needed on the role of mycorrhizas especially in the recovery of growth and nutrient uptake in cold soils in the spring. The HPFM is useful novel method for assessment of root damage.

2020 ◽  
Vol 67 (6) ◽  
pp. 985-1002 ◽  
Author(s):  
M. A. Lebedeva ◽  
Ya. S. Yashenkova ◽  
I. E. Dodueva ◽  
L. A. Lutova

Abstract Plant developmental processes are very flexible and highly depend on environmental factors. This is largely due to the existence of regulatory mechanisms that systemically control development on the whole plant level. In plants, regulatory peptides produced in the roots have been identified that are activated in response to different factors influencing root system, such as variation in the level of macronutrients (first of all, nitrogen and phosphorus) in the soil, influence of symbiotic microorganisms (soil rhizobial bacteria and arbuscular mycorrhiza fungi), and water deficiency. Among the systemically acting peptides, the most thoroughly investigated are CLE (CLAVATA3/EMBRYO SURROUNDING REGION-related) and CEP (C-TERMINALLY ENCODED PEPTIDES) peptides that are capable of travelling through the xylem from the roots to the shoot and triggering responses via binding to specific receptors operating in the phloem of the leaf. This review focuses on the role of these two groups of peptides in molecular dialog between the root and shoot.


2013 ◽  
Vol 41 (2) ◽  
pp. 313-318 ◽  
Author(s):  
Dorota Hilszczańska ◽  
Zbigniew Sierota

<em>Thelephora terrestris</em> (Erhr.) Fr. is a very common ectomycorrhizal symbiont (ECM) in conifer trees, however the role of this ubiquitous fungus in nurseries and Scots pine plantations is still unknown. It is described as tolerant of high nitrogen availability and therefore was taken into consideration as an important ECM partner of seedlings, particularly after replanting on post agricultural land. In laboratory the seedlings of Scots pine (<em>Pinus sylvestris</em> L.) were inoculated with <em>T. terrestris</em> (Tt/IBL/2) or not inoculated (control) and grown in containers in two different regimes of nitrogen fertilization (4g N x kg<sup>-1</sup> and 6 g N x kg<sup>-1</sup>). Next year these seedlings were outplanted in post agricultural land and 6 months later, the number and identity of some mycorrhizas were studied. It was found, that mycorrhizal abundance was higher in the inoculated treatments than in non-inoculated ones. PCR RFLP analysis confirmed share of two different isolates of <em>Thelephora</em> engaged in mycorrhizal symbiosis. Part of mycorrhizas had the same pattern of RFLP as the isolate used to inoculation. Similar results were obtained in second year of experimental study in the field what confirmed the persistence of artificially introduced <em>T. terrestris</em> in post agricultural soil as an important component of the ECM community.


2010 ◽  
Vol 18 (1) ◽  
pp. 152-157 ◽  
Author(s):  
Zhi-Yong ZHANG ◽  
Jian-Chu ZHENG ◽  
Hai-Qin LIU ◽  
Zhi-Zhou CHANG ◽  
Liu-Gen CHEN ◽  
...  

2006 ◽  
Vol 86 (2) ◽  
pp. 211-218 ◽  
Author(s):  
Denise Russowski ◽  
Natasha Maurmann ◽  
Sandra Beatriz Rech ◽  
Arthur Germano Fett-Neto

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1887
Author(s):  
Mei Han ◽  
Can Zhang ◽  
Peter Suglo ◽  
Shuyue Sun ◽  
Mingyao Wang ◽  
...  

L-aspartate (Asp) serves as a central building block, in addition to being a constituent of proteins, for many metabolic processes in most organisms, such as biosynthesis of other amino acids, nucleotides, nicotinamide adenine dinucleotide (NAD), the tricarboxylic acid (TCA) cycle and glycolysis pathway intermediates, and hormones, which are vital for growth and defense. In animals and humans, lines of data have proved that Asp is indispensable for cell proliferation. However, in plants, despite the extensive study of the Asp family amino acid pathway, little attention has been paid to the function of Asp through the other numerous pathways. This review aims to elucidate the most important aspects of Asp in plants, from biosynthesis to catabolism and the role of Asp and its metabolic derivatives in response to changing environmental conditions. It considers the distribution of Asp in various cell compartments and the change of Asp level, and its significance in the whole plant under various stresses. Moreover, it provides evidence of the interconnection between Asp and phytohormones, which have prominent functions in plant growth, development, and defense. The updated information will help improve our understanding of the physiological role of Asp and Asp-borne metabolic fluxes, supporting the modular operation of these networks.


2014 ◽  
Vol 44 (9) ◽  
pp. 1013-1019 ◽  
Author(s):  
Teija Ruuhola ◽  
Tarja Lehto

The role of mycorrhizas in the uptake of boron (B) is still poorly known; it has been suggested that ectomycorrhizas (ECM) may either increase B uptake or sequester B in forms unavailable for plants. We examined whether ECM infection affects the B uptake compared with nonmycorrhizal plants and whether two ECM fungal species differ in this respect. We inoculated silver birch (Betula pendula Roth) seedlings with either Paxillus involutus (Batsch) Fr. or Laccaria sp. Seedlings were fertilized with a complete nutrient solution including B. The whole-plant specific B uptake rates were slightly higher in Laccaria-inoculated seedlings than in noninoculated seedlings. Laccaria seedlings accumulated B transiently in their roots, which led to an increase in the specific leaf uptake rate of B in a later phase. Colonization of seedlings by Paxillus was low, and this fungus did not affect B uptake or allocation. The main result was that mycorrhizas did not affect B uptake and translocation negatively. An ability to accumulate B in mycorrhizas transiently might even make plants more tolerant to temporary B deficiency as they are not so strictly dependent on a continuous external B supply. However, the possibility of retention at very low B availability remains to be studied.


1995 ◽  
Vol 25 (1) ◽  
pp. 18-28 ◽  
Author(s):  
B.J. Hawkins ◽  
M. Davradou ◽  
D. Pier ◽  
R. Shortt

One-year-old seedlings of western red cedar (Thujapiicata Donn ex D.Don) and Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) were grown for one season in five nutrient treatments with nitrogen (N) supplied in solution at rates of 20, 100, or 250 mg•L−1 and phosphorus (P) supplied at rates of 4, 20, or 60 mg•L−1. Growth, onset of dormancy, frost hardiness on six dates, and foliar nutrient concentrations in autumn and spring were measured. Midwinter rates of net photosynthesis and transpiration were measured at air temperatures of 4, 7, and 11 °C in seedlings from all nutrient treatments. Recovery of net photosynthesis and transpiration in whole seedlings from the three N treatments was assessed at intervals for 28 days after the seedlings were frozen to −5, −15, and −25°C. Foliar N content differed significantly among nutrient treatments and was positively correlated with supply. Mitotic activity ceased earliest in plants with low N supply. Douglas-fir seedlings in the low-N treatment also ceased height growth earliest. These differences in growth had no significant correlation with frost hardiness. No consistent differences in frost hardiness among nutrient treatments were observed. Higher rates of N and P supply resulted in higher rates of winter net photosynthesis. Net photosynthesis was reduced dramatically by night frost, with greater damage occurring at lower temperatures. Net photosynthesis recovery occurred most quickly in seedlings with the midrate of N and P supply.


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