Root cap-mediated evaluation of soil resistance towards gravi-responding roots of maize (Zea mays L.) and the relevance of ethylene
Root cap-mediated evaluation of soil resistance towards gravi-responding roots of maize (Zea mays L.) and the relevance of ethylene
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DOI：
10.1093/aob/mcx209
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发表时间：
2018-10-05
期刊：
影响因子：
4.2
通讯作者：
Edelmann, Hans G.
中科院分区：
文献类型：
--
作者：
Dreyer, Julian;Edelmann, Hans G.
背景和目的除了生物和化学影响外，机械阻力也是根系生长面临的一个重要障碍。Gravirespmding根必须评估基质的机械阻力，并决定它们是否改变生长方向并在障碍物周围生长或耐受不同程度受损的生长条件。以检验根冠的重要性。我们测量了单个完整的以及去盖的根遇到不同机械障碍的压力和生长行为。我们研究了乙烯的排放在完整的根，以及根没有根冠，从而缺乏能力的偏差。方法固定幼苗的根垂直生长到不同的机械障碍。发展压力剖面垂直生长的根遇到水平的机械障碍，采用电子毫克尺度测量，有和没有根冠在给定的当地环境条件下。根传乙烯的演变进行了测量，在完整的根和根没有根冠。关键结果在开盖根相反，完整的根开发一个试探性的，短暂的压力分布，其分辨率的特点是由一个明确的变化的生长方向。同样。面对逐渐不同的表面阻力的根的压力分布和强度在两者之间显著不同。这在短期内与根帽依赖的乙烯排放，这是缺乏根无caps.Conclusions的方式gravistimated和gravesponsive根科普外源刺激取决于他们是否以及如何适应这些影响。关于机械障碍，根无帽似乎不能够评估土壤强度，以充分应对。在遇到抗性时，具有完整帽的根释放乙烯，这在去帽根中没有观察到。因此，似乎是根冠通过特异性诱导乙烯来特异性地协调克服机械抗性所需的抗性。
Background and Aims Besides biological and chemical impacts, mechanical resistance represents an important obstacle that growing roots face. Gravirespmding roots must assess the mechanical resistance of the substrate and take decisions on whether they change growth direction and grow around obstacles or tolerate growth conditions impaired to varying degrees. To test the significance of the root cap. we measured pressure and growth behaviour of single intact, as well as decapped, roots encountering diverse mechanical obstacles. We examined ethylene emission in intact roots as well as roots without a root cap, thereby lacking the capacity to deviate.Methods Roots of fixed seedlings were grown vertically onto diverse mechanical obstacles. Developing pressure profiles of vertically growing roots encountering horizontal mechanical obstacles were measured employing electronic milligram scales, with and without root caps in given local environmental conditions. The evolution of root-borne ethylene was measured in intact roots and roots without the root cap.Key Results In contrast to decapped roots, intact roots develop a tentative, short-lasting pressure profile, the resolution of which is characterized by a definite change of growth direction. Similarly. pressure profiles and strengths of roots facing gradually differing surface resistances differ significantly between the two. This correlates in the short term with root cap-dependent ethylene emission which is lacking in roots without caps.Conclusions The way gravistimulated and graviresponding roots cope with exogenous stimuli depends on whether and how they adapt to these impacts. With respect to mechanical hindrances, roots without caps do not seem to be able to evaluate soil strengths in order to respond adequately. On encountering resistance, roots with intact caps emit ethylene, which is not observed in decapped roots. It therefore appears that it is the root cap which specifically orchestrates the resistance needed to overcome mechanical resistance by specifically inducing ethylene.