Study on hemiparasitic mechanism of Thesium chinense / 中国中药杂志

ABSTRACT

<p><b>OBJECTIVE</b>To study the hemiparasitic mechanism of Thesium chinense.</p><p><b>METHOD</b>The anatomical structure of T. chinense was studied by using paraffin slice and electron microscope slice. Chlorophyll content was measured by UV spectrometry. Foliar photosynthesis (P(n)) and gas exchange were measured by using a LI-6400 photosynthesis system.</p><p><b>RESULT</b>Chloroplast possesses intact granal thylakoid system, lamella was strong. Vascular tissue of T. chinense was strong. Vessel aperture and its transport power were strong both in root and stem. There were many global haustoriums on lateral roots. Vascular tissues were strong inside haustorium, haustorial stylet penetrated epidermis and cortex of host root, and reached pith place, haustorial vessel was integrated with host root vessel. The maximum of P(n) of T. chinense reached 7.06 micromol x m(-2) x s(-1), its water use efficiency was lower, about 0.735 mmol x mol(-1), its transpiration varied notable in daytime and was relatively invariant at nighttime, and the value of daytime was greatly exceed that of nighttime.</p><p><b>CONCLUSION</b>T. chinense despoils water and nutrition from its host by haustorium. T. chinense can mostly be independent as for C supply by photosynthesis.</p>