根区温度影响黄瓜幼苗亚适温适应性的生理机制

发布时间：2018-01-26 17:07

  本文关键词： 根区温度 亚适温 根-冠关系 光合作用 养分吸收　出处：《中国农业大学》2016年博士论文　论文类型：学位论文

【摘要】：我国设施蔬菜冬春季节生产中的亚适温逆境是作物生长的主要限制因子。如何高效利用能源进行温室温度调控,以达到改善作物生长发育的目的,是现阶段可持续设施蔬菜生产需要解决的重要课题之一。本试验以黄瓜(Cucumis sativus L.)为试材,研究了改善根区温度缓解亚适温逆境下黄瓜幼苗生长和生理活性的相关机理,并通过不同气温处理比较地上-地下环境对作物生长平衡性的交互作用,以及通过加入聚乙二醇(polyethylene glycol,PEG)处理来分析改善根区温度过程中根源水分供应信号的贡献程度。主要结果如下：1)亚适温逆境下,黄瓜幼苗发育进程和生物量积累速率均受抑制,提升根区温度可以显著缓解生物量的积累速率,但无法促进新叶发生的进程。2)亚适温逆境下,黄瓜幼苗根系的生长和吸收功能都受到严重抑制,提升根区温度可以大幅增加黄瓜幼苗根系长度,其主根长、一级侧根和二级侧根的数目和长度均有显著提升。同时,根区升温能有效促进根系对各种矿质元素的吸收,其中对磷、钾、锰、锌和铜元素直接提升了单位根长的吸收速率,对氮、钙、镁和铁元素则主要是通过增加根系总长来增加总吸收量。3)亚适温逆境下,黄瓜幼苗叶片的光合能力受到不同程度的抑制。对于亚适温处理前已长成的真叶(第一真叶),根区升温能同时减轻其气孔限制与非气孔限制,即增大气孔导度,缓解Rubisco酶表达量和羧化活力,恢复光反应阶段质醌库的电子传递进程。对于亚适温处理期间新长出的真叶(第二真叶),根区升温减轻了气孔限制的程度,同时也能通过改善根系的水分供应来促进该叶片的扩展,使其叶面积达到未升温植株叶面积的两倍。4)在根区升温引起的变化中,黄瓜幼苗碳同化总量的提升平均有12%来自净光合速率的改善、平均88%来自叶面积的增长,而叶面积的增长几乎完全来自于比叶面积的增加；黄瓜幼苗氮同化总量的提升有平均16%来自吸收速率的提升、平均84%来自总根长的增长,而总根长的增长有70%来自比根长的增加、30%来自根系干重分配率的增加。对于幼苗全株干重的相对生长速率而言,不同方面性状的贡献程度,依次是同化活力构型特征生物量分配。5)根据本试验中的结果,在实际设施生产育苗过程中遭遇亚适温逆境时,如果没有日历苗龄的限制,则建议优先提升根区温度3-6℃以保证培育壮苗,如果有时间限制或亚适温持续时间过久时,则建议提升气温以促进幼苗的发育进程。
[Abstract]:The suboptimal temperature stress is the main limiting factor of crop growth in the winter and spring production of protected vegetables in China. How to efficiently use energy to regulate greenhouse temperature in order to improve the growth and development of crops. Cucumis sativus L. is one of the most important problems in the sustainable vegetable production at the present stage. Cucumis sativus L.was used as the test material in this experiment. The related mechanism of cucumber seedling growth and physiological activity under suboptimal temperature stress was studied and the interaction of aboveground and underground environment on crop growth balance was compared by different temperature treatments. And by adding polyethylene glycol polyethylene glycol. PEG) treatment was used to analyze the contribution of root water supply signal to the improvement of root temperature. The main results were as follows: 1) under suboptimal temperature stress, the growth process and biomass accumulation rate of cucumber seedlings were inhibited. Raising the root temperature significantly alleviated the biomass accumulation rate, but could not promote the process of new leaf occurrence. 2) under the suboptimal temperature stress, the growth and absorption function of cucumber seedling roots were seriously inhibited. The root length, the number and length of primary lateral root and secondary lateral root of cucumber seedlings were significantly increased by raising root zone temperature. At the same time, the root length of cucumber seedlings was increased significantly. Root heating can effectively promote the root absorption of various mineral elements, including phosphorus, potassium, manganese, zinc and copper elements directly increased the absorption rate per unit root length, nitrogen, calcium. Mg and Fe increased the total uptake by increasing the total root length. 3) under suboptimal temperature stress. The photosynthetic ability of cucumber seedling leaves was inhibited to some extent. For the true leaves which had grown before suboptimal temperature treatment (the first true leaf), the root zone warming could reduce both stomatal and non-stomatal limitation at the same time. That is to increase stomatal conductance, alleviate the activity of Rubisco enzyme expression and carboxylation, and restore the electron transfer process of the quinone library in the photoreaction stage, for the new true leaves (the second true leaf) during suboptimal temperature treatment. The root zone warming alleviated the stomatal limitation and promoted the leaf expansion by improving the water supply of the root system. The total carbon assimilation of cucumber seedlings increased by an average of 12% from the improvement of net photosynthetic rate. The average of 88% was from the increase of leaf area, and the increase of leaf area was almost entirely due to the increase of specific leaf area. The total nitrogen assimilation of cucumber seedlings increased by an average of 16% from the increase of absorption rate, an average of 84% from the increase of total root length, and an increase of 70% of total root length from the increase of specific root length. 30% from the increase of root dry weight allocation rate. For the relative growth rate of the whole plant dry weight of seedling, the contribution of different characters was different. According to the results of this experiment, if there is no calendar-seedling age limit in the process of seedling production in actual facilities, there is suboptimal temperature stress. It is suggested that the temperature of root zone should be raised to 3-6 鈩，

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