ABSTRACT
Air pollution and climate change amplify the urban heat island (UHI) effect, which has an adverse effect on human health. Urban forests (UFs) are important to reduce the UHI effect; however, the quantitative effect of UFs on UHI, relative to time and space, has not yet been investigated. In this study, we aimed to quantitatively measure the actual thermal environment in UFs. To this end, temperature and humidity loggers were installed in 17 UFs in Seoul for a year and analyzed according to vegetation characteristics and accessibility. The urban forests and park showed consistent temperature reduction, whereas the lawn showed higher temperature reduction effects during autumn-winter. The traffic island showed lower annual temperature reduction effect than other UFs. From spring to autumn, mixed and broadleaved forests showed better temperature reduction effect than coniferous forests. The temperature in UFs decreased by approximately 1.9°C over ~3 km from the traffic island near the city to the forest. This study revealed the difference in the cooling effect according to the type and location of UF and the vegetation structure. The functional characteristics of plants and the UF that reflects them can help reduce the negative impact of climate warming and UHI on human health.
Subject(s)
Forests , Hot Temperature , Humans , Seoul , Cities , Republic of KoreaABSTRACT
Some plant species develop aerenchyma to avoid anaerobic environments. In Syzygium kunstleri (King) Bahadur & R. C. Gaur, both primary and secondary aerenchyma were observed in adventitious roots under hypoxic conditions. We clarified the function of and relationship between primary and secondary aerenchyma. To understand the function of primary and secondary aerenchyma in adventitious roots, we measured changes in primary and secondary aerenchyma partial pressure of oxygen (pO2) after injecting nitrogen (N2) into the stem 0-3 cm above the water surface using Clark-type oxygen microelectrodes. Following N2 injection, a decrease in pO2 was observed in the primary aerenchyma, secondary aerenchyma, and rhizosphere. Oxygen concentration in the primary aerenchyma, secondary aerenchyma, and rhizosphere also decreased after the secondary aerenchyma was removed from near the root base. The primary and secondary aerenchyma are involved in oxygen transport, and in adventitious roots, they participate in the longitudinal movement of oxygen from the root base to root tip. As cortex collapse occurs from secondary growth, the secondary aerenchyma may support or replace the primary aerenchyma as the main oxygen transport system under hypoxic conditions.
ABSTRACT
Syzygium kunstleri, a woody plant species, adapts to hypoxic conditions by developing new adventitious roots. Here, we investigate its morphological adaptation to long-term water level changes and the sources and pathways of O2 supplied to its adventitious roots. Cuttings were cultivated in hydroponic and agar media, and then, the water level was increased by 6 cm following adventitious root emergence; afterward, O2 partial pressure changes were measured using a Clark-type O2 microelectrode. O2 concentrations in the adventitious roots decreased when N2 was injected, regardless of the presence of light, indicating that the O2 source was not photosynthetic when bark was removed. New adventitious roots developed near the surface when the water level increased, and O2 conditions above the raised water level influenced O2 concentrations in adventitious roots. O2 concentrations in adventitious roots that developed before the water level increased were lower than in the newly developed adventitious roots but increased when the O2 concentrations above the original water level increased. Our study highlights morphological changes, such as the development of adventitious roots, as environmental adaptation mechanisms. By revealing O2 sources in S. kunstleri under hypoxic environments, we offer insights into the challenges of long-term adaptation to changing environments in woody plants.
ABSTRACT
Cauliflower mushroom (Sparassis latifolia or S. crispa) is popular for food and medicine. Importance of new varieties of Sparassis was raised and studied widely by protection system of UPOV. In this study, 10 crossbred strains of Sparassis latifolia that specifically expressed distinctive features during basidiocarp formation and mycelium growth were applied to sawdust medium inoculated with S. latifolia mycelia. The 10 crossbred strains were divided into 3 groups on the basis of morphological (size of marginal wave and basidiocarp color) and genetic characteristics. Each phenotype of the parent and crossbred strains represented 3 marginal wave-sizes (large, medium, and small) and 3 color notations (NN155D, 163C, and 8D). Our result suggests that morphological characteristics of cauliflower mushroom can be affected by various environmental and genetic stimuli under artificial conditions such as crossbreed. Also this research showed genetic differences among breeding isolates and their morphological characteristics were correlated with the molecular data within parent and crossed strain.
Subject(s)
Polyporales/growth & development , Polyporales/genetics , Crosses, Genetic , Genotype , PhenotypeABSTRACT
Recent studies based on morphological characteristics and molecular analyses have revealed that the characteristics of Sparassis crispa from Asia are not concordant with those of collections from Europe and North America. Consequently, the Asian isolate was redefined as Sparassis latifolia. This study is the first report of Sparassis latifolia collected in Korea. The taxonomic relationships and replacement of Sparassis species were inferred from a comparison of the morphological characteristics and by molecular sequence analysis of the internal transcribed spacer (ITS) rDNA regions. In particular, this study focused on the phylogenetic relationships inferred from the biogeographical distribution of isolates within the genus Sparassis.