Search Results

You are looking at 1 - 10 of 409 items for

  • Author or Editor: Chen Chen x
Clear All Modify Search
Free access

Weixin Chen

Lychee is a well-known subtropical fruit, much appreciated for its attractive red peel and excellent taste, but the fruit is very prone to postharvest peel browning and decay. China is the world leader in both acreage and yield of lychee production. Extensive research has been conducted to extend the fruit quality and shelf life. The talk presents a general review of the current research on postharvest physiology and shelf life preservation technologies of lychee in China.

Free access

Chen-Yen Chang and Ping-Kun Chen

The purpose of this paper was to report the effects of window views and indoor plants on human psychophysiological response in workplace environments. The effects of window views and indoor plants were recorded by measuring participant's electromyography (EMG), electroencephalography (EEG), blood volume pulse (BVP), and stateanxiety. Photo Impact 5.0 was used to simulate the environment in an office, where six conditions were examined: 1) window with a view of a city, 2) window with a view of a city and indoor plants, 3) window with a view of nature, 4) window with a view of nature and indoor plants, 5) office without a window view, and 6) office without a window view and indoor plants. Participants were less nervous or anxious when watching a view of nature and/or when indoor plants were present. When neither the window view nor the indoor plants were shown, participants suffered the highest degree of tension and anxiety.

Free access

J. Chen and O. Lamikanra

Angular leaf spot is a common but rarely studied disease of muscadine grapes (Vitis rotundifolia Michx.) in the southeastern United States. During 1994 and 1995, we performed two field evaluations of angular leaf spot on 30 muscadine cultivars. Based on disease severity data, no cultivar was immune to angular leaf spot; however, `Albermarle', `Doreen', `Higgins', `Noble', `Regale', `Scuppernong', `Southland', and `Summit' showed high degrees of resistance. `Alachua', `Darlene', `Dixie Red', `GA-3-9-2', `Jane Bell', `Janet', `Jumbo', `Pam', and `Rosa' were susceptible.

Free access

Qibing Wang and Jianjun Chen*

Ficus benjamina is considered to have a high degree of morphological and physiological plasticity in response to light levels. In this study, leaf area and thickness, specific leaf area (SLA), chlorophyll content, and photosynthetic characteristics of Ficus benjamina `Common'; grown in a shaded greenhouse under four maximum photosynthetic photon flux densities (PPFDs) of 150, 250, 450, or 650 μmol·m-2·s-1 were investigated. Results showed that plants grown under 450 and 650 PPFDs had higher SLA and leaf thickness but smaller leaf areas than those grown under 150 and 250 PPFDs. Total chlorophyll content per unit leaf area decreased as PPFDs increased. Net photosynthetic rates (Pn) increased from 2.7 μmol·m-2·s-1 under 150 PPFD to 5.7 μmol·m-2·s-1 under 450 PPFD, then slightly decreased to 5.5 μmol·m-2·s-1 under 650 PPFD. The highest net photosynthetic rate was not associated with higher intercellular CO2 concentrations (Ci) and stomatal conductance (gs) as plants grown under 250 PPFD had the highest (Ci) (259 ppm) and gs (0.1 mol·m-2·s-1), which suggests that photosynthetic enzymes could play a increasing role under 450 PPFD. Plant quality, however, was not necessarily correlated with the Pn because only those grown under 250 PPFD had appropriate heights, large and dark green leaves, and well-spread branches, and thus were graded higher than plants grown under the other PPFDs. This study shows that fine-tuning production light level is important for high quality Ficus benjamina production.

Free access

Wen-Shaw Chen

The changes in cytokinins and gibberellins in xylem sap of lychee (Litchi chinensis Sonn. cv. Heh yeh) trees were investigated at the stages of leaf expansion, dormant bud (when apical leaves are dropped), 30 days before flower bud formation, flower bud formation, and full bloom of grafted field-grown lychee trees. Also; the diffusible IAA and ABA in diffusate from shoot tips were examined at the successive stages of development. High gibberellin was found in the xylem sap at the stage of leaf expansion. A constant level of IAA was maintained through the five growth stages. At 30 days before flower bud formation, ABA increased dramatically. Concurrently, total cytokinin content increased in the xylem sap, reaching a maximum during flower bud formation and full bloom. Gibberellin content in the xylem sap was at a low level 30 days before flower bud formation and through the stage of flower bud formation.

Free access

Lianghong Chen and Mack Nelson

Randomly amplified polymorphic DNA (RAPD) technique is based on DNA amplification by polymerase chain reaction (PCR) of random DNA segments using single arbitrary nucleotide sequences. It has been widely used for genetic mapping, plant and animal breeding programs, and DNA fingerprinting. However, there is no single set of RAPD-PCR conditions that can be applied to all situations. In order to adjust reaction component concentrations within suggested ranges for efficient amplification during the use of RAPD in detection of genetic variation of genus Camellia, crucial factors, such as concentrations of MgCl2 and DNA, annealing temperature (37 to 44 °C), and the use of an AmpliTaq® DNA polymerase and Stoffel fragment were examined. Five camellia cultivars, `Winter's Beauty', `Pink Icicle', `Polar Ice', `Winter's Hope', and `Snow Flurry', were under investigation. Clear and reproducible amplification products were produced with 3.0 μM MgCl2 and 30 ng template DNA/25 μL reaction mixer at annealing temperature 37 °C and 40 °C, compared with MgCl2 at 1.5, 2.0, and 2.5 μM. When annealing temperature increased, the RAPD-PCR stringency was increased, as expected. Stoffel fragment was found to provide highly reproducible results.

Free access

Yan Ma and Junyu Chen

From 1986 through 1993 wild rose species were investigated throughout China to catalog and to characterize the rose germplasm resources in mainland China. Many of the 94 rose species and 144 rose varieties in China have not been extensively utilized. The basic features of Chinese rose species are as follows. (1) There are many valuable and rare Rosa species in China. These species are sources of many unique and outstanding characters such as intense fragrance, white and yellow flower color, recurrent flowering and resistance to stress. More than 80% of the rose species in China are native to only China. (2) Although most Rosa species are still in the wild state, a few species cultivated from very early time have many forms available. (3) The number of rose species gradually increases from Northeast to Southwest China. The distribution centers of Rosa species in China are Sichuan and Yunnan Provinces. Chinese rose species can be introduced and used directly in gardens, or in breeding programs to develop new roses.

Free access

Grace Q. Chen

To improve the potential of Lesquerella fendleri as a valuable industrial oilseed crop, a stable genetic transformation system was developed. Genetic transformation was performed by inoculating leaf segments with an Agrobacterium tumefaciens strain AGL1 containing binary vector pCAMBIA 1301.1, which contains a β-glucuronidase gene as a reporter gene and hygromycine phosphotransferase II as a selection marker gene. Primary shoots were regenerated from the leaf segments on the half-strength Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurine, 1-naphthaleneacetic acid, and hygromycin. The frequency of primary shoot generation was between 22.5% and 60%, and 81.1% to 89.3% of these shoots were chimeras. The high frequency of chimeras was probably the result of efficient protection from the hygromycin of non-transformed cells by adjacent transformed ones. The non-transformed cells were removed by multiple rounds of successive shoot regenerations. The purified isogenic shoots were subcultured and roots were induced on the MS medium plus indole-3-butyric acid. Most of the plantlets were able to establish roots and acclimate successfully in the greenhouse. The insertion of the hptII gene was confirmed by segregation analysis in T1 seeds, and the stable inheritance of the transgenes was demonstrated by the characterization transgenic lines through T2 generation. This transformation system can be used to obtain stable transgenic lines for genetic engineering of L. fendleri.

Free access

Yifan Jiang, Xinlu Chen, Hong Lin, Fei Wang and Feng Chen

Volatile chemicals emitted from the flowers of chinese wisteria (Wisteria sinenesis) and japanese wisteria (W. floribunda) were collected using a dynamic headspace technique and identified using gas chromatography–mass spectrometry; 28 and 22 compounds were detected from chinese wisteria and japanese wisteria flowers, respectively. These chemicals can be classified into four major classes, including fatty acid derivatives, benzenoids/phenylpropanoids, terpenoids, and nitrogen-containing compounds. Two monoterpenes, (E)-β-ocimene and linalool, belonging to the class of terpenoids, were the most abundant compounds emitted from both species. Despite strong similarity, the floral volatile profiles of the two species displayed variations in both quality and quantity. Chinese wisteria was selected as a model for further study of volatile emission from different parts of flowers, emission dynamics, and regulation of floral scent production. Although floral volatiles were detected from all flower parts, petals emitted the most. The emission of floral volatiles displayed a diurnal pattern with the maximal emissions occurring during the daytime. This rhythmic pattern was determined to be light-dependent. Regulation of floral volatile emission by exogenous chemicals, including silver thiosulphate (an ethylene inhibitor), salicylic acid, and jasmonic acid, also was analyzed. Generally, jasmonic acid promoted the emission of floral volatiles. In contrast, neither silver thiosulphate nor salicylic acid showed a significant effect on floral volatile emission. The results presented in this article suggest that wisteria can serve as a useful system for exploring novel biochemistry of floral scent biosynthesis. They also build a foundation for the study of the biological/ecological significance of floral volatiles on the reproductive biology of wisteria species.

Free access

Suping Zhou, Fur-Chi Chen, Samuel Nahashon and Tingting Chen

Photorespiration provides a protection mechanism in plants by diverting excessive energy accumulated from photochemical reaction, metabolizing toxic products and producing some protective molecules. The authors report cloning and characterization of a glycolate oxidase gene (GOX; NCBI accession DQ442286) and a NADH-dependent hydroxypyruvate reductase gene (HPR; NCBI DQ442287) from Pachysandra terminallis. The DQ442286 had the predicted GOX-like–Riboflavin-5′-phosphate (FMN) conserved domain and the DQ442287 had the predicted adenosine 5′-(alpha-thio)diphospho-5′-ribofuranosylnicotinamide nicotinamide adenine dinucleotide (NAD) binding domain (2-Hacid_DH_C). C-terminal peroxisome targeting signal was predicted to be -ARL for DQ442286 and –SKL for DQ442287. Both genes encoded enzyme proteins that are located in peroxisome and are involved in the photorespiration process. Real-time quantitative reverse-transcriptase polymerase chain reaction was performed to compare transcript level of the cloned genes after cold treatment. The 18s Ribosomal RNA (rRNA) was included to calibrate the data. The relative cycle threshold values (gene/18s rRNA) were 1.4, 1.5, and 1.5 for GOX and 1.2, 1.3, and 1.3 for HPR in the treatments of 4 °C 4 h, 4 °C 12 h, and control. The data revealed that gene expression was enhanced by only short-term (4-h) cold treatment. A ribulose-1, 5-biphosphate carboxylase/oxygenase (Rubisco) activase gene (DQ 486905) was also cloned and analyzed following the same procedure.