Frontiers of torenia research: innovative ornamental traits and study of ecological interaction networks through genetic engineering

Advances in research in the past few years on the ornamental plant torenia (Torenia spps.) have made it notable as a model plant on the frontier of genetic engineering aimed at studying ornamental characteristics and pest control in horticultural ecosystems. The remarkable advantage of torenia over other ornamental plant species is the availability of an easy and high-efficiency transformation system for it. Unfortunately, most of the current torenia research is still not very widespread, because this species has not become prominent as an alternative to other successful model plants such as Arabidopsis, snapdragon and petunia. However, nowadays, a more global view using not only a few selected models but also several additional species are required for creating innovative ornamental traits and studying horticultural ecosystems. We therefore introduce and discuss recent research on torenia, the family Scrophulariaceae, for secondary metabolite bioengineering, in which global insights into horticulture, agriculture and ecology have been advanced. Floral traits, in torenia particularly floral color, have been extensively studied by manipulating the flavonoid biosynthetic pathways in flower organs. Plant aroma, including volatile terpenoids, has also been genetically modulated in order to understand the complicated nature of multi-trophic interactions that affect the behavior of predators and pollinators in the ecosystem. Torenia would accordingly be of great use for investigating both the variation in ornamental plants and the infochemical-mediated interactions with arthropods

The dynamic changes of stable isotopic ratios of carbon and nitrogen in suspended and sedimented particulate organic matter during a phytoplankton bloom

The dynamic changes of carbon and nitrogen stable isotopic ratios in suspended and sedimented particulate matter were observed together with many other chemical and biological properties during a phytoplankton bloom induced by nutrient addition in a controlled ecosystem enclosure (CEE, about 70 m3) in Saanich Inlet, British Columbia, Canada. Both of the stable isotopic ratios of carbon (δ13C) and nitrogen (δ15N) in suspended particulate organic matter showed characteristic patterns of variations in surface water during the bloom. The δ13C of suspended particulate matter increased with the growth of phytoplankton population and decreased gradually after the depletion of NO3− and NO2−. The δ15N of suspended particulate matter was very low soon after the beginning of phytoplankton bloom, but the value increased rapidly with the decrease in NO3− and NO2−, and reached maximal value following nutrient depletion, after which the δ15N remained high until the end of the experiment. In order to understand such variations of δ13C and δ15N, we made the mass and isotopic balance models of carbon and nitrogen for the upper layer of the CEE, and simulated the temporal variations of δ13C and δ15N of particulate organic matter using them in connection with several hypotheses on the isotope fractionations associated with the uptake of inorganic substrates by phytoplankton. While neither change in the dissolved inorganic carbon (i.e., its isotope ratio and/or molecular CO2 concentration) nor the phytoplankton species compositions can well explain the variation of δ13C, this variation can be well simulated considering the effect of change in the specific production rate of particulate organic carbon. On the other hand, the variations of δ15N can be clearly understood by a first-order isotope fractionation model under the assumption of large isotopic fractionation during the assimilation of NO3− and NO2− by phytoplankton. The particulate organic matter produced in the nutrient controlled phytoplankton bloom can be classified into three phases from an isotopic viewpoint: (I) the early stage of the phytoplankton bloom when NO3− plus NO2− were still in excess in sea water (high δ13C but low δ15N), (II) the late stage of the bloom when NO3− plus NO2− had just been depicted (high δ13C and high δ15N) and (III) the steady state phase, a few days after the depletion of NO3− plus NO2− (low δ13C but high δ15N). The cooperative variation of δ13C and δ15N in the suspended and sedimented particulate organic matter was also demonstrated

The 225-year precipitation variability inferred from tree-ring records in Shanxi Province, the North China, and its teleconnection with Indian summer monsoon

Understanding the interactions between the East Asian summer monsoon and Indian summer monsoon is a challenging task because of the insufficient proxy records. In this study, we reconstructed a 225-year precipitation record by combining ring widths of Pinus tabulaeformis and stable oxygen isotope ratios of Larix principis-rupprechtii using a multi-proxy dendroclimatology approach in the North China. The reconstructed record explained 51.9% of the variance in the observed precipitation during 1955–2003. The precipitation series could indicate the intensity of the East Asian summer monsoon. A spatial field analysis indicated that the series was strongly correlated with the reconstructed records of the surrounding area and a large part of the Indian subcontinent. The reconstructed records were significantly and positively correlated with All Indian Precipitation records (r = 0.32, n = 132, p < 0.001) and with a proxy of the Indian summer monsoon. These findings suggest that a persistent teleconnection exists between the reconstructed record and the Indian summer monsoon records from the past 225 years. The observed interannual synchronisation potentially resulted from the transport of partial water vapour from the Indian summer monsoon area to NC; however, this synchronisation could not be attributed to the El Nino-South Oscillation (ENSO). When considering an interdecadal time scale, the synchronisation with the North Atlantic Oscillation (NAO) has varied since 1779, implying that the NAO may serve as an additional atmospheric pattern that affects this teleconnectio

Tree-ring reconstructed summer temperature anomalies for temperate East Asia since 800 C.E.

We develop a summer temperature reconstruction for temperate East Asia based on a network of annual tree-ring chronologies covering the period 800–1989 C.E. The East Asia reconstruction is the regional average of 585 individual grid point summer temperature reconstructions produced using an ensemble version of point-by-point regression. Statistical calibration and validation tests indicate that the regional average possesses sufficient overall skill to allow it to be used to study the causes of temperature variability and change over the region. The reconstruction suggests a moderately warm early medieval epoch (ca. 850–1050 C.E.), followed by generally cooler ‘Little Ice Age’ conditions (ca. 1350–1880 C.E.) and 20th century warming up to the present time. Since 1990, average temperature has exceeded past warm epochs of comparable duration, but it is not statistically unprecedented. Superposed epoch analysis reveals a volcanic forcing signal in the East Asia summer temperature reconstruction, resulting in pulses of cooler summer conditions that may persist for several years. Substantial uncertainties remain, however, particularly at lower frequencies, thus requiring caution and scientific prudence in the interpretation of this record

Increased Variability of Thailand\u27s Chao Phraya River Peak Season Flow and Its Association With ENSO Variability: Evidence From Tree Ring δ\u3csup\u3e18\u3c/sup\u3eO

We present a statistically robust reconstruction of Thailand\u27s Chao Phraya River peak season streamflow (CPRPF) that spans the 202 years from 1804 to 2005 CE. Our reconstruction is based on tree ring δ18O series derived from three Pinus merkusii sites from Laos and Thailand. The regional δ18O index accounts for 57% of the observed variance of CPRPF. Spatial correlation and 21‐year running correlation analyses reveal that CPRPF is greatly influenced by regional precipitation variations associated with the El Niño–Southern Oscillation (ENSO). Periods of enhanced and reduced ENSO activity are associated with strong and weak ENSO‐streamflow correlation, respectively. At the longer timescale, the Pacific Decadal Oscillation (PDO) appears to modulate the ENSO‐streamflow correlations, with the most extreme flood events along the Chao Phraya River occurring during periods of increased frequency of La Niña events that coincide with extended cold phases of the PDO. The CPRPF reconstruction could aid management planning for Thailand\u27s water resources

Recent enhancement of central Pacific El Niño variability relative to last eight centuries

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