秤锤树属与长果安息香属植物的地理分布及其濒危现状

秤锤树属(SinojackiaHu)和长果安息香属(ChangiostyraxC.T.Chen)是安息香科的少种属,这两属在我国共记录有7个种。本文通过野外调查,分析了中国这两属植物的地理分布、濒危现状及其迁地保护状况。结果表明:秤锤树属植物地理分布较广,但是每个物种的居群数量和居群大小均很小。其中秤锤树(Sinojackiaxylocarpa)和狭果秤锤树(S.rehderiana)已经在其模式标本产地灭绝;棱果秤锤树(S.henryi)在过去的近70年内没有采到过标本,该物种可能存在同物异名现象或已经灭绝;细果秤锤树(S.microcarpa)由于人为破坏严重,居群大小急剧下降;肉果秤锤树(S.sarcocarpa)和怀化秤锤树(S.oblongicarpa)呈零星分布且个体数量很少,处于极濒危状态。另外本次调查发现秤锤树属的一个新的分类群(待鉴定种)。秤锤树属的大多数种和长果安息香属植物的居群更新能力差:虽然结果率较高,但是结籽率较低;坚硬的内果皮阻碍了种子的萌发,这是其居群更新的最大障碍;另外人为破坏对其居群更新的影响也较大。作者建议应该把秤锤树属的所有物种和长果安息香属植物都纳入保护的范围并讨论了这两属植物的保护策略。     

茉莉酸类与植物地下贮藏器官的形成

茉莉酸类化合物(茉莉酸及其衍生物)可能参与了马铃薯、薯蓣、菊芋的块茎,甘薯的块根以及洋葱、大蒜的鳞茎形成。JA及MeJA均可诱导离体条件下马铃薯块茎的形成和马铃薯髓部细胞的膨大。JA诱导细胞膨大是由于蔗糖积累导致渗透压增加以及细胞壁结构变化,从而使其伸展性增加,纤维素的合成起了重要作用,细胞骨架也是JA诱导细胞膨大所必需的。但迄今为止,尚未确定块茎形成的直接诱导物。     

New pyrrolo[3,2-b]pyrroles with AIE characteristics for detection of dichloromethane and chloroform

Three new pyrrolo[3,2-b]pyrrole derivatives containing methoxyphenyl, pyrene or tetraphenylethylene (TPE) units (compounds 1 – 3) have been designed, synthesized and fully characterized. The aggregation-induced emission (AIE) properties of compounds 1 – 3 were tested in different water fraction (f_w) of tetrahydrofuran (THF). The pyrrolo[3,2-b]pyrrole derivative 3 containing TPE units exhibited typical AIE features with an enhanced emission (∼32-fold) in the solid state versus in solution; compounds 1 and 2 exhibited an aggregation-caused quenching effect. In addition, the steric and electronic effects of the peripheral moieties on the emission behavior, both in solution and in the solid state, have been investigated. Moreover, pyrrolo[3,2-b]pyrrole 1 exhibits high sensitivity and selectivity for dichloromethane and chloroform solvents, with the system displaying a new emission peak and fast response time under ultraviolet irradiation.     

Characterization and acceleration of genome shuffling and ploidy reduction in synthetic allopolyploids by genome sequencing and editing

Polyploidy and the subsequent ploidy reduction and genome shuffling are the major driving forces of genome evolution. Here, we revealed short-term allopolyploid genome evolution by sequencing a synthetic intergeneric hybrid (Raphanobrassica, RRCC). In this allotetraploid, the genome deletion was quick, while rearrangement was slow. The core and high-frequency genes tended to be retained while the specific and low-frequency genes tended to be deleted in the hybrid. The large-fragment deletions were enriched in the heterochromatin region and probably derived from chromosome breaks. The intergeneric translocations were primarily of short fragments dependent on homoeology, indicating a gene conversion origin. To accelerate genome shuffling, we developed an efficient genome editing platform for Raphanobrassica. By editing Fanconi Anemia Complementation Group M (FANCM) genes, homoeologous recombination, chromosome deletion and secondary meiosis with additional ploidy reduction were accelerated. FANCM was shown to be a checkpoint of meiosis and controller of ploidy stability. By simultaneously editing FLIP genes, gene conversion was precisely introduced, and mosaic genes were produced around the target site. This intergeneric hybrid and genome editing platform not only provides models that facilitate experimental evolution research by speeding up genome shuffling and conversion but also accelerates plant breeding by enhancing intergeneric genetic exchange and creating new genes.