Inducing bark inclusions in branch junctions of aspen (Populus tremula L.) by bracing them with horticultural wire

Abstract Background Bioconversion of wood into bioproducts and biofuels is hindered by the recalcitrance of woody raw material to bioprocesses such as enzymatic saccharification. Targeted modification of the chemical composition of the feedstock can improve saccharification but this gain is often abrogated by concomitant reduction in tree growth. Results In this study, we report on transgenic hybrid aspen (Populus tremula × tremuloides) lines that showed potential to increase biomass production both in the greenhouse and after 5 years of growth in the field. The transgenic lines carried an overexpression construct for Populus tremula × tremuloides vesicle-associated membrane protein (VAMP)-associated protein PttVAP27-17 that was selected from a gene-mining program for novel regulators of wood formation. Analytical-scale enzymatic saccharification without any pretreatment revealed for all greenhouse-grown transgenic lines, compared to the wild type, a 20–44% increase in the glucose yield per dry weight after enzymatic saccharification, even though it was statistically significant only for one line. The glucose yield after enzymatic saccharification with a prior hydrothermal pretreatment step with sulfuric acid was not increased in the greenhouse-grown transgenic trees on a dry-weight basis, but increased by 26–50% when calculated on a whole biomass basis in comparison to the wild-type control. Tendencies to increased glucose yields by up to 24% were present on a whole tree biomass basis after acidic pretreatment and enzymatic saccharification also in the transgenic trees grown for 5 years on the field when compared to the wild-type control. Conclusions The results demonstrate the usefulness of gene-mining programs to identify novel genes with the potential to improve biofuel production in tree biotechnology programs. Furthermore, multi-omic analyses, including transcriptomic, proteomic and metabolomic analyses, performed here provide a toolbox for future studies on the function of VAP27 proteins in plants.

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Allelopathic effects of leachates of Juglans regia L., Populus tremula L. and juglone on germination of temperate zone cultivated medicinal and aromatic plants

Agroforestry Systems ◽

10.1007/s10457-020-00572-9 ◽

2021 ◽

Vol 95 (2) ◽

pp. 431-442

Author(s):

Péter Zubay ◽

Jakob Kunzelmann ◽

András Ittzés ◽

Éva Németh Zámboriné ◽

Krisztina Szabó

Keyword(s):

Current Knowledge ◽

Juglans Regia ◽

Agroforestry Systems ◽

Temperate Zone ◽

Populus Tremula ◽

Environmental Benefits ◽

Allelopathic Effect ◽

Aromatic Plants ◽

Medicinal And Aromatic Plants ◽

Allelopathic Effects

AbstractThe environmental benefits of agroforestry systems are well known. However, current knowledge of potential allelopathic interactions is inadequate. The decrease in soil fertility, the increasingly rhapsodic distribution of precipitation, and the special metabolism and cultivation of medicinal and aromatic plants are all harbingers of medicinal-agroforestry systems. The authors aimed to discover the allelopathic effects of Juglans regia L. and Populus tremula L. on germination of medicinal and aromatic plants cultivated in a temperate zone. Accordingly, an in vitro germination trial was conducted with leachates of these trees and two juglone concentrations. These allelopathic effects were evaluated for germination vigour, germination rate, and total fresh weight of seedlings of twelve different species. A pronounced species specificity was observed in tolerance of seeds and seedlings to the allelopathic effect of Populus and Juglans. In four of the species studied, the allelopathic effect may inhibit germination, but only initially. Poppy and angelica proved to be the most sensitive to the treatments. The following species had relative tolerance to the allelochemicals, so further research under natural conditions is suggested for: Althea officinalis L. (9.34 ± 5.04–68.66 ± 13.62 GR%), Anethum graveolens L. (12.00 ± 2.00–100.00 ± 6.12 GR%), Cannabis sativa L. (72.66 ± 9.02–91.34 ± 1.16 GR%), Dracocephalum moldavica L. (38.00 ± 2.00–80.00 ± 17.44 GR%), Linum usitatissimum L. (44.66 ± 2.00–58.00 ± 3.46 GR%), and Satureja hortensis L. (52.00 ± 28.22–82.00 ± 8.00 GR%). The aim would be to introduce them into agroforestry systems.

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