Photoperiodic long-day control of sporophyll and hair formation in the brown alga Undaria pinnatifida

Two photoperiodic responses, the development of sporophylls and hairs, have been quantified in sporophytes of the brown alga Undaria pinnatifida. In a final experiment, the algae were cultivated in outdoor, 2000-L seawater tanks in a greenhouse for up to 12 weeks, and daylength was regulated by automatic blinds mounted on top of the tanks. Vegetative young sporophytes were treated under short-day (SD; 8 h light per day) or long-day conditions (LD; 16 h light per day), at 12 h light per day or in a night-break regime (NB; 8 h light per day, 7.5 h dark, 1 h light, 7.5 h dark). The earliest sporophyll development was observed 6, 7 or 9 weeks under LD, NB or SD conditions, respectively. After 12 weeks the sporophylls were significantly longer and wider under LD or NB conditions than in the SD regime, and only half of the experimental algae had formed sporophylls under SD conditions, but all algae under LD or NB conditions. In a foregoing 7-week culture experiment performed in 300-L indoor tanks, enhanced sporophyll formation had also been observed under LD and not under SD conditions (NB omitted). In both experiments, blade elongation rates remained high until the end of the experiments in SD, but declined during sporophyll initiation in LD, NB or at 12 h light per day. Another difference caused by photoperiod was observed in regard to the development of surface hair spots which occurred in both experiments on the blades in LD, NB or at 12 h light per day with identical densities, but were completely lacking under SD conditions. It is concluded that U. pinnatifida is a facultatative long-day plant in regard to reproduction forming vigorously sporophylls in long days, and an obligate long-day plant in regard to hair formation.

Impact of astaxanthin-enriched algal powder of Haematococcus pluvialis on memory improvement in BALB/c mice

The impact of astaxanthin-enriched algal powder on auxiliary memory improvement was assessed in BALB/c mice pre-supplemented with different dosages of cracked green algal (Haematococcus pluvialis) powder daily for 30 days. The supplemented mice were first tested over 8 days to find a hidden platform by swimming in a Morris water maze. Then, for 5 days, the mice were used to search for a visible platform in a Morris water maze. After that, the mice practised finding a safe place-an insulated platform in a chamber-for 2 days. During these animal experimental periods, similar algal meals containing astaxanthin at 0, 0.26, 1.3 and 6.4 mg/kg body weight were continuously fed to each group of tested mice. Profiles of latency, distance, speed and the direction angle to the platforms as well as the diving frequency in each group were measured and analyzed. The process of mice jumping up onto the insulated platform and diving down to the copper-shuttered bottom with a 36 V electrical charge were also monitored by automatic video recording. The results of the Morris maze experiment showed that middle dosage of H. pluvialis meals (1.3 mg astaxanthin/kg body weight) significantly shortened the latency and distance required for mice to find a hidden platform. However, there was no obvious change in swim velocity in any of the supplemented groups. In contrast, the visible platform test showed a significant increase in latency and swim distance, and a significant decrease in swim speed for all groups of mice orally supplemented with H. pluvialis powder compared to the placebo group (P < 0.05 or P < 0.01). Mice supplemented with the algal meal hesitantly turned around the original hidden platform, in contract to mice supplemented with placebo, who easily forgot the original location and accepted the visible platform as a new safe place. These results illustrate that astaxanthin-enriched H. pluvialis powder has the auxiliary property of memory improvement. The results from the platform diving test showed that the low and middle dosage of H. pluvialis powder, rather that the high dosage, increased the latency and reduced the frequency of diving from the safe insulated platform to the electrically stimulated copper shutter, especially in the low treatment group (P < 0.05). These results indicate that H. pluvialis powder is associated with dose-dependent memory improvement and that a low dosage of algal powder (<= middle treatment group) is really good for improving the memory.

汉语口语句子产生中语义和语音信息的水平流动

As Levelt and Meyer (2000) noted, because studies of lexical access during multiword utterances production such as phrases and sentences, they raise two novel questions which studies of single word production do not. Firstly, does the access of different words in a sentence occur in a parallel or a serial fashion? Secondly, does the access of the different words in a sentence occur in an interactive or a discrete fashion? The latter question concerns the horizontal information flow (Smith & Wheeldon, 2004), which is a very important aspect of continuous speech production. A variant of the picture–word interference paradigm combining with eye-tracking technique and a dual task paradigm was used in 7 experiments to investigate the horizontal information flow of semantic and phonological information between nouns in spoken Mandarin Chinese sentences. The results suggested that: 1. Before speech onset, semantic information of different words accross the whole sentence has been activated, while phonological activation has been limited within the first phrase of the sentence. 2. Before speech onset, speaker will look ahead and check the semantic information of latter words as the first noun is beening processed, such looking ahead for phonological information can just occur within the first phrase of the sentence. 3. After speech onset, speaker will concentrate on the content words beyond the first one and will check the semantic information of other words with the same sentence. 4. The result suggested that the lexical accesses of multiple words during spoken sentence production are processed in a partly serial and partly parallel manner and stands for the Unit-by-Unit and Incremental view proposed by Levelt (2000). 5. The horizontal information flow during spoken sentence production is not an automatic process and is constrained by cognitive resource.