Comparative Transcriptome Sequencing and Endogenous Phytohormone Content of Annual Grafted Branches of Zelkova schneideriana and Its Dwarf Variety HenTianGao.

Zelkova schneideriana is a fast-growing tree species endemic to China. Recent surveys and reports have highlighted a continued decline in its natural populations; therefore, it is included in the Red List of Threatened Species by The International Union for Conservation of Nature. A new variety "HenTianGao" (H) has been developed with smaller plant height, slow growth, and lower branching points. In this study, we attempted to understand the differences in plant height of Z. schneideriana (J) and its dwarf variety H. We determined the endogenous hormone content in the annual grafted branches of both J and H. J exhibited higher gibberellic acid (GA)-19 and trans-Zeatin (tZ) levels, whereas H had higher levels of indole-3-acetic acid (IAA) catabolite 2-oxindole-3-acetic acid (OxIAA), IAA-Glu conjugate, and jasmonic acid (JA) (and its conjugate JA-Ile). The transcriptome comparison showed differential regulation of 20,944 genes enriched in growth and development, signaling, and metabolism-related pathways. The results show that the differential phytohormone level (IAA, JA, tZ, and GA) was consistent with the expression of the genes associated with their biosynthesis. The differences in relative OxIAA, IAA-Glu, GA19, trans-Zeatin, JA, and JA-Ile levels were linked to changes in respective signaling-related genes. We also observed significant differences in the expression of cell size, number, proliferation, cell wall biosynthesis, and remodeling-related genes in J and H. The differences in relative endogenous hormone levels, expression of biosynthesis, and signaling genes provide a theoretical basis for understanding the plant height differences in Z. schneideriana.

The extract of Celtis choseniana Nakai alleviates testosterone-induced benign prostatic hyperplasia through inhibiting 5α reductase type 2 and the Akt/NF-κB/AR pathway.

Benign prostatic hyperplasia (BPH) is a chronic male disease characterized by the enlarged prostate. Celtis chosenianaNakai (C. choseniana) is medicinally used to alleviate pain, gastric disease, and lung abscess. In this study, the effect of C. choseniana extract on BPH was investigated using testosterone-induced rats. Sprague Dawley rats were divided into five groups: control, BPH (testosterone 5 mg·kg-1), Fina (finasteride 2 mg·kg-1), and C. choseniana (50 and 100 mg·kg-1). After four weeks of TP treatment with finasteride or C. choseniana, prostate weights and DHT levels were measured. In addition, the prostates were histopathologically examined and measured for protein kinase B (Akt)/nuclear factor-κB (NF-κB)/AR signaling, proliferation, apoptosis, and autophagy. Prostate weight and epithelial thickness were reduced in the C. choseniana groups compared with that in the BPH group. The extract of C. choseniana acted as a 5α reductase inhibitor, reducing DHT levels in the prostate. Furthermore, the extract of C. choseniana blocked the activation of p-Akt, nuclear NF-κB activation and reduced the expression of AR and PSA compared with BPH. Moreover, the expression of Bax, PARP-1, and p53 increased, while the expression of bcl-2 decreased. The present study demonstrated that C. choseniana extract alleviated testosterone-induced BPH by suppressing 5α reductase and Akt/NF-κB activation, reducing AR signaling and inducing apoptosis and autophagy in the prostate. These results suggested that C. choseniana probably contain potential herbal agents to alleviate BPH.

The extract of Celtis choseniana Nakai alleviates testosterone-induced benign prostatic hyperplasia through inhibiting 5α reductase type 2 and the Akt/NF-κB/AR pathway / 中国天然药物

Benign prostatic hyperplasia (BPH) is a chronic male disease characterized by the enlarged prostate. Celtis chosenianaNakai (C. choseniana) is medicinally used to alleviate pain, gastric disease, and lung abscess. In this study, the effect of C. choseniana extract on BPH was investigated using testosterone-induced rats. Sprague Dawley rats were divided into five groups: control, BPH (testosterone 5 mg·kg-1), Fina (finasteride 2 mg·kg-1), and C. choseniana (50 and 100 mg·kg-1). After four weeks of TP treatment with finasteride or C. choseniana, prostate weights and DHT levels were measured. In addition, the prostates were histopathologically examined and measured for protein kinase B (Akt)/nuclear factor-κB (NF-κB)/AR signaling, proliferation, apoptosis, and autophagy. Prostate weight and epithelial thickness were reduced in the C. choseniana groups compared with that in the BPH group. The extract of C. choseniana acted as a 5α reductase inhibitor, reducing DHT levels in the prostate. Furthermore, the extract of C. choseniana blocked the activation of p-Akt, nuclear NF-κB activation and reduced the expression of AR and PSA compared with BPH. Moreover, the expression of Bax, PARP-1, and p53 increased, while the expression of bcl-2 decreased. The present study demonstrated that C. choseniana extract alleviated testosterone-induced BPH by suppressing 5α reductase and Akt/NF-κB activation, reducing AR signaling and inducing apoptosis and autophagy in the prostate. These results suggested that C. choseniana probably contain potential herbal agents to alleviate BPH.

Stomatal and non-stomatal limitations in savanna trees and C4 grasses grown at low, ambient and high atmospheric CO2.

By the end of the century, atmospheric CO2 concentration ([CO2]a) could reach 800 ppm, having risen from ∼200 ppm ∼24 Myr ago. Carbon dioxide enters plant leaves through stomata that limit CO2 diffusion and assimilation, imposing stomatal limitation (LS). Other factors limiting assimilation are collectively called non-stomatal limitations (LNS). C4 photosynthesis concentrates CO2 around Rubisco, typically reducing LS. C4-dominated savanna grasslands expanded under low [CO2]a and are metastable ecosystems where the response of trees and C4 grasses to rising [CO2]a will determine shifting vegetation patterns. How LS and LNS differ between savanna trees and C4 grasses under different [CO2]a will govern the responses of CO2 fixation and plant cover to [CO2]a - but quantitative comparisons are lacking. We measured assimilation, within soil wetting-drying cycles, of three C3 trees and three C4 grasses grown at 200, 400 or 800 ppm [CO2]a. Using assimilation-response curves, we resolved LS and LNS and show that rising [CO2]a alleviated LS, particularly for the C3 trees, but LNS was unaffected and remained substantially higher for the grasses across all [CO2]a treatments. Because LNS incurs higher metabolic costs and recovery compared with LS, our findings indicate that C4 grasses will be comparatively disadvantaged as [CO2]a rises.

Strategy for Screening of Antioxidant Compounds from Two Ulmaceae Species Based on Liquid Chromatography-Mass Spectrometry.

Liquid chromatography-mass spectrometry (LC-MS)-based untargeted metabolomics implies that annotated metabolites can serve as potential markers of the associated bioactivities of plant extracts. Firstly, we selected Aphananthe aspera and Zelkova serrata (Family: Ulmaceae) from 16 Korean plant species based on their distinct principal component analysis (PCA) patterns in LC-MS datasets and antioxidant activity assays. Further, we chose 40% solid-phase extraction (SPE) extracts of the two species displaying the highest antioxidant activities coupled with distinct PCA patterns. Examining the metabolite compositions of the 40% SPE extracts, we observed relatively higher abundances of quercetin, kaempferol, and isorhamnetin O-glucosides for A. aspera, whereas quercetin, isorhamnetin O-glucuronides, and procyanidin dimer were relatively higher in Z. serrata. These metabolites were clearly distinguished in pathway map and displayed strong positive correlations with antioxidant activity. Further, we performed preparative high-performance liquid chromatography (prep-HPLC) analysis coupled with the 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) assay to validate their functional correlations. As a result, quercetin O-sophoroside was determined as the main antioxidant in A. aspera, while isorhamnetin O-glucuronide and procyanidin dimer were the primary antioxidants in Z. serrata. The current study suggests that the LC-MS-based untargeted metabolomics strategy can be used to illuminate subtle metabolic disparities as well as compounds associated with bioactivities.

Nocturnal and seasonal patterns of carbon isotope composition of leaf dark-respired carbon dioxide differ among dominant species in a semiarid savanna.

The C isotope composition of leaf dark-respired CO(2) (δ(13)C(l)) integrates short-term metabolic responses to environmental change and is potentially recorded in the isotopic signature of ecosystem-level respiration. Species differences in photosynthetic pathway, resource acquisition and allocation patterns, and associated isotopic fractionations at metabolic branch points can influence δ(13)C(l), and differences are likely to be modified by seasonal variation in drought intensity. We measured δ(13)C(l) in two deep-rooted C(3) trees (Prosopis velutina and Celtis reticulata), and two relatively shallow-rooted perennial herbs (a C(3) dicot Viguiera dentata and a C(4) grass Sporobolus wrightii) in a floodplain savanna ecosystem in southeastern Arizona, USA during the dry pre-monsoon and wet monsoon seasons. δ(13)C(l) decreased during the nighttime and reached minimum values at pre-dawn in all species. The magnitude of nocturnal shift in δ(13)C(l) differed among species and between pre-monsoon and monsoon seasons. During the pre-monsoon season, the magnitude of the nocturnal shift in δ(13)C(l) in the deep-rooted C(3) trees P. velutina (2.8 ± 0.4‰) and C. reticulata (2.9 ± 0.2‰) was greater than in the C(3) herb V. dentata (1.8 ± 0.4‰) and C(4) grass S. wrightii (2.2 ± 0.4‰). The nocturnal shift in δ(13)C(l) in V. dentata and S. wrightii increased to 3.2 ± 0.1‰ and 4.6 ± 0.6‰, respectively, during the monsoon season, but in C(3) trees did not change significantly from pre-monsoon values. Cumulative daytime net CO(2) uptake was positively correlated with the magnitude of the nocturnal decline in δ(13)C(l) across all species, suggesting that nocturnal δ(13)C(l) may be controlled by (13)C/(12)C fractionations associated with C substrate availability and C metabolite partitioning. Nocturnal patterns of δ(13)C(l) in dominant plant species in the semiarid savanna apparently have predictable responses to seasonal changes in water availability, which is important for interpreting and modeling the C isotope signature of ecosystem-respired CO(2).

[Environmental responses of four urban tree species transpiration in northern China].

By using thermal dissipation probes (TDP), this paper monitored the sap flow of four tree species (Cedrus deodara, Zelkova schneideriana, Euonymus bungeanus, and Metasequoia glyptostroboides) at the Laodong Park in Dalian City from June to August 2008, and the soil moisture content and micrometeorological variables were mehsured simultaneously. Due to the absence of water-stress in the habitat, the sap flow of all sampled trees had no significant correlation with soil moisture content (R2 < 0.050, P > 0.211, n=1296). The correlation coefficient between solar radiation and sap flow reached 0.624-0.773 (P = 0.00, n=1296) despite the existing hysteresis. Solar radiation had major effect (R2 > 0.700, P < 0.05) during early morning (5:00-8:00) and late afternoon (18:00-20:00) when undergoing dramatic changes. As the main factor determining nighttime sap flow (R2 > 0.660, P < 0.05, n=1872), vapor pressure deficit (VPD) had a correlation coefficient as high as 0.650-0.823 (P = 0.00, n=1296) with the sap flow in whole-day scale. Meanwhile, the models constructed on the basis of VPD were able to explain 90% of daily sap flow change (P = 0.00). The correlation coefficient between sap flow and wind speed was relatively smaller than the previous two (R2 < 0.380, P = 0.00, n=1296), though showing significant correlation in affecting sap flow. Observations also detected the saturation phenomenon of sap flow to the environmental demands.

Contrasting patterns of hydraulic redistribution in three desert phreatophytes.

We measured sap flow in taproots, lateral roots and stems within a single individual in each of three co-occurring tree species in a Chihuahuan desert arroyo to assess the seasonality and magnitude of hydraulic redistribution. Nocturnal reverse flow (hydraulic redistribution) was detected in shallow lateral roots of Fraxinus velutina and Juglans major during periods when surface soils were dry. Reverse flow in the Fraxinus lateral root ranged from near zero to 120 g h(-1), and was inversely correlated with nighttime vapor pressure deficit (D), suggesting that nighttime transpiration may have inhibited hydraulic redistribution. Reverse flow in the Juglans lateral root ranged from near zero to 18 g h(-1). There was no relationship between reverse flow and nighttime D in the Juglans lateral root, despite a weak positive relationship between nighttime D and rates of basipetal flow (flow towards the stem) in the taproot. Reverse flow in Fraxinus and Juglans ceased when surface soils were wetted by monsoon rains and flooding. We found no reverse flow or seasonal variation in root sap flow in Celtis reticulata. However, basipetal sap flow in Celtis roots continued throughout most of the evening, even during periods when D was near zero, and commenced in the morning more than two hours after the onset of sap flow in the main stem. Patterns of nocturnal root sap flow in Celtis may have been facilitated by the diurnal withdrawal from, and refilling of above ground storage compartments (i.e. above ground diurnal storage capacity), which may have prevented hydraulic redistribution. Species differences in nocturnal root function may have significant impacts on ecosystem hydrological fluxes, and should be considered when scaling fluxes to catchment, landscape, and regional levels.

Stem diameter changes before bud opening in Zelkova serrata saplings.

It is well known that stems of woody plants shrink and swell diurnally. These fluctuations of stem diameter are induced mainly by the changes of water contents in plants, which are caused by the combination of leaf transpiration and root absorption of water. This implies that dormant-like deciduous broadleaved trees in a leafless state should show no or less changes in stem diameter. However, some physiological activities in woody plants are also known to precede their winter bud opening. Whether and how diameter changes occur in deciduous tree stems during winter was investigated using Zelkova serrata saplings in a leafless state. Measurements of stem diameter changes were done for more than 4 months continuously. The saplings showed distinct diameter changes with periodicities from diurnal to a few weeks, and these changes were initiated 2 months before winter bud opening. These results indicate that some physiological and/or developmental activities occur in the stem of deciduous trees before winter bud opening, and do not correspond to changes in water relations as a result of leaf transpiration. These internal activities cause fluctuations in stem diameter prior to winter bud opening in deciduous trees.