Trees最新文献

Key message

The study found that higher winter temperatures lead to an increase in respiratory carbon loss in Norway spruce and silver fir seedlings. The growth of Norway spruce negatively correlated with winter temperature, but we observed no effect for silver fir.

Abstract

Climate change is significantly altering the carbon sequestration potential of European forest ecosystems. Elevated winter temperatures at high latitudes can have a negative impact on the carbon balance and subsequent growth of evergreen trees. This study aimed to test the hypothesis of a negative impact of elevated winter temperature on winter respiration, carbon balance and growth of evergreen coniferous trees in Denmark. Seedlings of Abies alba and Picea abies were exposed to elevated temperatures (2–8 °C increase) for one month during the winter of 2020 using outdoor infrared heaters and greenhouses. Both species showed a significant increase in respiration under higher temperatures, possibly negatively affecting their total leaf carbon balance. Dark respiration increased by 15–16% per 1 °C increase in the monthly average temperature for both species. Neither Abies alba nor Picea abies showed downregulation of dark respiration under prolonged elevated temperatures. Radial and height growth in the following season was negatively correlated with winter temperature treatment for Picea abies, but not for Abies alba. Unfortunately, the Picea abies seedlings were attacked by aphids which could affect the growth as well. Further research focused on the impact of winter warming on carbohydrate reserves is needed to fully understand why warming winters negatively affect the growth of some evergreen conifers, but not others.

Key message

Scleroderma bermudense improves growth and physiological traits of seagrape exposed to salt stress in planting.

Abstract

In Cuba (The Greater Antilles), Coccoloba uvifera L., (Polygonaceae), an ectomycorrhizal (ECM) fruit tree also called seagrape, is among the earliest plant colonizers of sandy and rocky shores within its natural range, and often grows near the tidal swing zone subject to salinity. Here, we assessed the persistence of pre-inoculation beneficial effects on seagrape seedlings in nursery and planting with Scleroderma bermudense Coker to restore a degraded sand dune of Cuba. While growth of ECM plants versus non-ECM plants was not significant at 2 months in nursery, differences in the growth promotion of ECM seagrape seedlings were improved at 3, 6, 9, and 12 months after planting. Using morphological and molecular analysis of ITS from ectomycorrhizae, it was found that S. bermudense successfully colonized and established in the absence of native ECM fungi on seagrape roots in nursery and field conditions. Consequently, the beneficial effects of the ECM symbiosis on growth and functional traits, such as photosynthetic and transpiration rates, chlorophyll fluorescence and content, stomatal conductance, sub-stomatal CO_2, and water status, resulted in improved growth performance of seagrape exposed to salt stress in planting. This study provided first insight on the use of ECM seagrape to restore degraded coastal ecosystems subject to salty, sandy, nutrient-poor soils in Cuba.

Key message

Significant improvement in salt tolerance of poplar hybrids with different salt 2 tolerant varieties.

Abstract

Salt stress is a global environmental factor that limits plant growth and productivity. Poplar has the characteristics of fast growth and fine texture, and the adaptability of hybrid plants to environmental stress is better than that of their parents. In this study, Populus simonii ‘CAFDF’ (♀), P. nigra ‘CAFDM’ (♂), P. simonii × P. nigra CV. ‘CAFDS2’ (DS2), and Populus simonii × P. nigra CV. ‘CAFDS3’ (DS3) were used to reveal the response and adaptation mechanism of the photosynthetic function of hybrid poplar leaves to salt stress by physiological combined with transcriptome technology. The results showed that NaCl stress significantly reduced the chlorophyll content of the leaves of both parents, but the reduction of chlorophyll in hybrid offspring under salt stress was lower than that in parents. A Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of differentially expressed genes (DEGs) in both hybrid plants and biparental progenies under NaCl stress was enriched for photosynthesis-antenna proteins, photosynthesis, and carbon fixation in photosynthetic organisms. Under salt stress treatment, the ability of leaves in DS2 and DS3 plants to capture solar energy and transfer their excitement energy to the reaction center were higher than that of their parental plants. NaCl stress caused damage to photosystem II (PSII) and photosystem I (PSI) in poplar leaves, and their activities decreased. The hybrid offspring improved the integrity of PSII receptor side electron transfer and donor side oxygen-evolving complex (OEC) compared with the two parents. The expression of other coding genes of the PSII reaction center, as well as coding genes for PSI reaction center and ATP synthetase in the hybrid offspring under NaCl stress are higher than that of the parents, which reduces damage to the electron transfer chain and the energy supply required for maintaining plant growth and development. The cyclic electron flow dependent on PGR5 and NDH pathways (PGR5-CEF and NDH-CEF) of hybrids and female parents were significantly higher than those of male parents. Hybrid progeny and the maternal parent alleviated the damage of salt stress on PSII and PSI by promoting CEF. The hybrid plants protect the photosynthetic apparatus by regulating energy dissipation, while the PSII of the parents plants was damaged due to serious photooxidation. Under salt stress, the net photosynthetic rate (P_n) in hybrid plants increased, and the non-stomatal factors, which was also confirmed by the Calvin cycle.

Key message

Superior F₁ mulberry genotypes with high leaf yield, quality, and moderate to high stability were identified for optimal and sub-optimal input conditions.

Abstract

Mulberry (Morus spp.) is a highly heterozygous, perennial tree widely grown for its foliage to feed monophagous silkworms (Bombyx mori L.) and fruits for human consumption across the globe. The present study evaluated twenty-one F₁ mulberry genotypes for the selection of superior ones based on leaf yield, yield attributes, leaf quality, and stability over two years under optimal and sub-optimal input (irrigation and fertilizer) conditions. Based on pooled data analysis over four crop seasons, it was found that six mulberry genotypes, D16, D21, D22, D23, D28, and D67, had leaf yields (663–840 g/plant) statistically similar to or better than the Vishala check (663 g/plant) under optimal conditions. Similarly, under sub-optimal conditions, seven genotypes, D16, D21, D22, D23, D24, D28 and D34, showed significantly higher leaf yields (418–596 g/plant) than Vishala (415 g/plant). The δ¹³C (a surrogate trait of water-use efficiency) of five mulberry genotypes, D16, D21, D24, D28, and D34, varied from – 28.21 to – 28.98 and was similar to the AGB8 check (– 28.87). Total soluble sugar, protein, chlorophyll content, and the silkworm moulting percentage and single larval weight for the seven genotypes D16, D21, D22, D23, D24, D28, and D34 were statistically similar to or better than Vishala under both optimal and sub-optimal conditions. The additive main effects and the multiplicative interaction-based simultaneous selection index showed that these seven genotypes had moderate to high stability and high leaf-yielding ability over the seasons under both optimal and sub-optimal conditions. DNA fingerprint profiles of these selected genotypes have been developed for their molecular identification. Under this context, these seven genotypes might be further tested under advanced evaluation trials to identify the best one regarding leaf yield and quality under optimal and sub-optimal conditions.

Key message

Phase transitions of the AMO and PDO promote shifts in non-summer hydrothermal conditions, which further affect tree growth in north subtropical China.

Abstract

Based on tree-ring samples collected from Shiyan, Hubei Province, a region with superior hydrothermal conditions during summer, we produced a 188-year standardized tree-ring width (STD) chronology, and calculated the accumulated anomalies of the STD chronology (STD_A) to obtain more significant, low-frequency periodic signals. The response analysis showed that the restrictive effect of climate on tree growth was mainly manifested through the positive influence of non-summer (previous September to current May) precipitation and the negative influence of the maximum temperature during the previous autumn and winter (September‒December). Moisture conditions in the current April‒May were particularly critical for early tree growth. The different growth stages represented in the STD chronology indicated that a wet–cold non-summer climate was more conducive to rapid tree growth. Power spectrum analysis results indicated that hydrothermal variations in this area may be influenced by the El Niño–Southern Oscillation (ENSO) and sunspot activity at high frequencies and by Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO) at low frequencies. Further analyses yielded that phase transitions of AMO and PDO promoted shifts in non-summer hydrothermal conditions, which further drove tree growth in the study area. At the same time, the partial correlation results emphasized that AMO mainly regulated precipitation variability, whereas PDO had a more pronounced effect on temperature variability. These insights will improve future decisions related to tree growth to cope with climate forcings based on regional hydrothermal evolution.

Key message

Our results from transcriptomics and metabolomics extend the understanding of the consequences of interspecific grafting to improve blueberry fruit quality.

Abstract

Grafting plays an important role in improving fruit quality and plant stress resistance. The effect of interspecific grafting on fruit quality in ‘O'Neal’ blueberry (Vaccinium corymbosum L.) was investigated with transcriptomics and non-targeted metabolomics. Fruits were collected from own-rooted ‘O'Neal’ (NO), ‘O'Neal’ grafted on ‘Tifblue’ (V. virgatum Ait.) (TO), and ‘Anna’ (V. corymbosum L.) (AO) bushes. The total soluble solids and anthocyanin concentrations, and solid:acid ratio in TO fruits were higher, while the vitamin C level was lower than AO and NO. The metabolic profiling showed that interspecific grafted blueberry had higher levels of sugars such as glucose, maltose, raffinose, myo-inositol, and galactinol, as well as glucose-6-phosphate and trehalose-6-phosphate as compared to intraspecific grafted blueberry. The fruits of TO also showed higher concentrations of secondary metabolites such as catechin, 5,7-dihydroxy-4'-methoxyisoflavone, glycyl tyrosine, and tocopherol, and lower concentrations of tryptophan and phenylalanine as compared to AO. Transcriptomic data showed that not only sugar metabolism-related enzymes such as trehalose-phosphate synthase and galactol synthase but also shikimate-derived metabolism-related enzymes such as flavonoid 3'-monooxygenase, anthocyanidin glucosyltransferase, isoflavone reductase, alcohol dehydrogenase, and aspartate aminotransferase were up-regulated in a comparison of TO/AO. Moreover, sugar signaling-related genes such as 6-phosphofructokinase, bHLHs, MYBs, 1-aminocyclopropane-1-carboxylate oxidase, 1-aminocyclopropane-1-carboxylate synthase, ABC transporter, and malate transporter were also up-regulated in a comparison of TO/AO. Finally, we proposed the hypothesis that sugar signals regulate the accumulation of sugars and organic acids and fruit ripening. These results will provide interesting insights into the interaction of scions on rootstocks and the promotion of blueberry genetic improvement.

Key message

The growth characteristics and biomass model of Cupressus gigantea (34a). The biomass of each part of the tree was ranked in order of size: trunk > main branches > leaves > lateral branches > roots > fruits, with the trunk and main branches dominating, and the biomass model was best fitted by a ternary linear regression model.

Abstract

Biomass models are the most widely used method for forest biomass estimation. Cupressus gigantea, an endemic species of Tibet, is mainly concentrated in southeastern Tibet, but few studies focus on cypress biomass to date. In this paper, The study of the growth characteristics and biomass model can provide a theoretical basis for the protection and field investigation and monitoring of the Cupressus gigantea, and can simplify the method and difficulty of field investigation. Tree data was collected by felling Cupressus gigantea (34a), then measure tree rings, DBH (diameter at breast height) and tree height. Linear and nonlinear regression models were used to eliminate heteroscedasticity using the least square method. Growth characteristics of 0–34 years Cupressus gigantea was obtained, and a biomass model was established. Among the 34-year-old Cupressus gigantea studied, the growth rate was slow from 0 to 10 years old and accelerated from 10 to 30 years old. The average biomass of the whole plant was 369.7 kg, of which the trunk accounted for 47.45%, with the biomass of each part ranking as follows: trunk > main branches > leaves > lateral branches > roots > fruit. The trunk, branches, above ground and below ground parts were modeled according to the basic model, 19 models met the standard for tree models, with R² values above 0.96. The fitting effect of models established in different parts varies greatly. The MPE (Average estimated Error) of the aboveground biomass was between 1.0 and 3.5%, while that of the belowground biomass was above 5%. By comparing the evaluation indexes of various models, it is found that the comprehensive prediction ability of linear model is better than that of nonlinear model. The comprehensive prediction ability of ternary linear model is the best among the five models, but binary linear and nonlinear models are more suitable for practical application.

Key message

There is a trade-off between plant water transport safety and efficiency, which may be linked to pit ultrastructure traits.

Drought-induced embolism is one of the most important causes of plant death, and there is a close relationship between the formation and spreading of embolism and xylem structure. However, many previous studies on xylem structure lack detailed observation in intervessel pits, especially pit membranes, which have important roles in water transport and embolism spreading for angiosperms. Here, we selected eight species from subtropical forests and studied their xylem structure and functional traits. The results showed that there was a trade-off between hydraulic transport safety and efficiency in eight species, which may be related to their xylem structure. The diameter of pit aperture and pit membrane, as well as the pit membrane thickness, showed significant relationships with xylem embolism resistance, indicating that the ultrastructure of intervessel pits was a good predictor for xylem safety. With detailed observation in pits ultrastructure, this study helps to elucidate the response mechanism of trees to drought and predict forest distribution and succession.