Comparison of physiological and yield traits between purple- and white-pericarp rice using SLs.

Five physiological and eleven yield traits of two pairs of sister lines generated from a high generation with similar genetic background (SLs) for purple pericarp were investigated to explore the reasons behind low-yield production of colored rice. Of the five physiological traits examined, except grain anthocyanin content, there were generally similar trends between the P (purple-pericarp) lines and the corresponding W (white-pericarp) lines over two seasons (in the year 2009 and 2010 separately). The results demonstrated that the chlorophyll content of flag leaves, the net photosynthetic rate of flag leaves, and the grain anthocyanin content could be easily influenced by the environment. The physiological functions of the traits for the P lines were more active than those of the corresponding W lines in the year 2010. The grain anthocyanin content of the P lines was much greater in the year 2010 than in the year 2009 during the growth period. The investigation of yield traits revealed that the P lines had reduced 1000-grain weight, yield per plot and grain/brown rice thickness compared to the W lines. A difference comparison of these traits and a source-sink and transportation relationship analysis for these SLs suggested that small sink size was a key reason behind yield reduction of purple pericarp rice.

[Inhibitory effects of exogenous abscisic acid and maleic hydrazide on panicle sprouting in hybrid rice F1].

"On-panicle seed sprouting" is a serious obstacle in hybrid rice seed production. It was reported that exogenous ABA inhibited seed sprouting of hybrid rice F(1) seeds. It was shown that by ABA 1000 mg/L or MH 4000 mg/L application at 21 d after full heading (filling stage)(Fig.1), not only seed sprouting was inhibited, but also the seed energy was affected (Fig.2). The retardation of germination and lowing of germination rate were resulted from ABA treatment and MH treatment respectively (Fig.3). When the seeds were treated with ABA, GA(1) level was decreased (Fig.4). The expression of amylase was delayed and their levels become lowed by ABA treatment (Fig.5). However, those seeds maintained a certain level of GA(1) and amylase and still have germination ability. During germination, the GA(1) content and amylase activity did not decrease significantly by MH treatment, but the GA(1) content and amylase activity were significantly decreased in non-germination MH treated seeds (Fig.4, 5). Therefore, the sprouting retarding effects of ABA was considered as "post-harvest effects" and sprouting inhibiting effect of MH was considered as "inhibition effects" by the authors.

[Transcription factors in higher plant].

Transcription factors play important roles in the regulation of plant growth and development, as well as its response to environment. A typical higher plant transcription factor usually contains a DNA-binding domain, a transcription regulation domain, oligomerization site and a nuclear localization domain. Transcription factors interact with cis-elements and regulate the expression of target genes through these domains. Recent studies show that transcription factors are efficient new molecular tools for the manipulation of plant growth and development. In this review, we will summarize the current knowledge in the study of higher plant transcription factor, with emphasis on the regulation of transcription factor on higher plant development and morphogenesis, as well as the application of transcription factor in plant improvement.