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| DOI：10.13522/j.cnki.ggps.2019387 |
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| The Effects of Soil Matric Potential on Fluorescence Characteristics of Chlorophyll and Growth of Taxus Chinensis Seedlings under Drip Irrigation |
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ZHANG Yuhao, YAO Sumei*, MENG li, DENG Zhe
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School of Life Science and Technology, Henan Institute of Science and Technology, Xinxiang 453003, China
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| Abstract: |
| 【Background】Taxus chinensis is a valuable medicinal herb and the paclitaxel in it can inhibit tumor growth. Clinical tests have shown that it is effective in treating many types of advanced cancers. As such, the demand for paclitaxel has increased over recent years. Wild Taxus chinensis grows slowly and is less competitive in natural environment. Exploitation of the wild types over the past decades has driven it almost to extinction. Domestic cultivation is essential to keep germplasm of Taxus chinensis from extinction, in which irrigation plays an important role. Drip irrigation is a micro-irrigation technology and can control soil moisture by automation. It is not only water use efficient but also improves plant yield and quality. Current research on drip irrigation focused on greenhouse crops and there is a paucity of study on its application in medicinal plants.【Objective】The objective of this paper is to experimentally investigate the effects of soil matric potential controlled by drip irrigation on fluorescence characteristics of chlorophyll and growth of the Taxus chinensis seedlings.【Method】The Tai Hang Taxus chinensis seedlings grown in pots was used as model plant. The matric potential at the depth of 20 cm underneath the drip emitter was kept at -10 kPa (F0), -20 kPa (F1), -30 kPa (F2), -40 kPa (F3) and -50 kPa (F4) respectively by adjusting the dripping rate. During the experiment, growth traits of the plant were recorded and the fluorescence parameters of the chlorophyll were measured monthly using a PAM-2500 Portable Chlorophyll Fluorometer.【Result】①As time elapsed in spring, the F0, Fm, Fv/Fm and Fv/F0 in the seedlings decreased, while qP, NPQ, ETR and Y(II) increased. The seedlings growing under low soil matric potential endured a slight water stress, but they remained resilient. In summer, F0, Fm, Fv/Fm and Fv/F0 did not show significant change, whereas qP, ETR and Y(Ⅱ) monotonically decreased and NPQ increased first followed by a decline. High soil matrix potential benefited photosynthetic electron transfer and opening of the PS(II) reaction center, but the seedling growing in low soil matrix potential still had a certain light protection ability. ②Plant height, ground diameter and crown breadth of the seedling peaked at matric potential of -20 kPa at late stage of the experiment.【Conclusion】Taxus chinensis seedlings can withstand water stress to certain extent. Keeping the soil matrix potential at the depth of 20 cm below the emitter at -20 kPa appeared to be optimal to benefit growth of the Taxus chinensis seedlings. |
| Key words: Taxus chinensis seedlings; drip irrigation; soil matric potential; fluorescence characteristics chlorophyll |
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