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Translocation of photosynthates in Undaria pinnatifida

Meng Jianxin, Wu Chaoyuan

Institute of Oceanology, The Chinese Academy of Sciences. Qingdao, Shandong

Abstract

Analysis of the samples from different parts of the blade and the counterparts exposed to tracer (NaH~(14)CO_(3))showed that translocation occurred mainly from the tip of the blade to the growing region with an apparent source-sink relationship. It took 20 min to translocate the labelled photosynthates from the epidermis, via cortex, to the medulla of the midrib. In the midrib, rates of translocation averaging 42~48cm/h were observed in the open sea. After being freeze-sectioned and freezedried, the samples were used in the study on the pathway of translocation in the midrib by autoradiographic method. It was found that most photosynthates were confined to trumpet-shaped cells in medulla. These data in dicate that the conduction of photosyn-thates takes place in the medulla and trumpet-shaped cells are the main conducting elements. Of the alcohol-soluble photosynthates translocated downward, more than 50% was found to be mannitol. Free amino acids such as Glu, Asp and Ala were also found in the ~(14)C-labelled photosynthates.

Key words: Undaria;Pinnatifida translocation photosynthate

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Citing This Article：

Meng Jianxin, Wu Chaoyuan. Translocation of photosynthates in Undaria pinnatifida. Acta Physiol Sin 1994; 46 (4): (in Chinese with English abstract).