The functional role of the photosynthetic apparatus in the recovery of Brassica napus plants from pre-emergent metazachlor exposure

详细信息    查看全文

• 作者：H. Vercampt^a ; L. Koleva^b ; A. Vassilev^b ; N. Horemans^c ; G. Biermans^d ; J. Vangronsveld^a ; A. Cuypers^a ; ^{ann.cuypers@uhasselt.be" class="auth_mail" title="E-mail the corresponding author}
• 关键词：F ; fluorescence intensity ; F0 ; minimal fluorescence (dark-adapted leaves) ; Fm ; maximal fluorescence (dark-adapted leaves) ; Fv/Fm ; maximal quantum yield of PSII ; Fm&rsquo ; maximal fluorescence (light-adapted leaves) ; Y ; effective quantum yield of PSII ; qP ; photochemical quenching (fraction of open PSII reaction centres) ; qN ; non-photochemical quenching (NPQ of variable chlorophyll fluorescence) ; NPQ ; fraction of non-photochemical quenching  ; =  ; (Fm  ; &minus ;   ; Fm&rsquo ; )/Fm ; ETR ; el
• 刊名：Journal of Plant Physiology
• 出版年：2016
• 出版时间：1 June 2016
• 年：2016
• 卷：196-197
• 期：Complete
• 页码：99-105
• 全文大小：872 K

文摘

Metazachlor is a chloroacetamide herbicide, frequently used in Brassica napus cultivations around the world. Its primary target is the inhibition of very long chain fatty acid biosynthesis. This study included a morphological and physiological screening of hydroponically grown B. napus, exposed to a concentration range of 0, 0.25, 0.50, 0.75 and 1.0 kg metazachlor per hectare. The results indicate that within a month after application, growth and development of B. napus are severely affected by low metazachlor doses. At intermediate metazachlor concentrations, loss of phosphorous and potassium from the plant tissues suggests destabilisation of cellular membranes, which may be a direct consequence of metazachlor application. This membrane instability could be indirectly linked with alterations of electron transport and a reduction of carbon assimilation. At increased metazachlor doses of 0.75 kg a.i. ha⁻¹, pigment concentrations are strongly reduced. However, chlorophyll fluorescence parameters seem to remain unaffected at metazachlor doses up to 0.75 kg a.i. ha⁻¹. At a metazachlor concentration of 1.0 kg a.i. ha⁻¹, negative effects are observed on all tested parameters, resulting in limited survival. The results indicate photosynthesis is assured at intermediate metazachlor concentrations for the cost of growth and development. It is clear that photosynthesis plays a key role in the survival strategy of young plants to overcome initially induced chemical stress.