高光适应的天竺葵插条中受氮和贮藏影响的碳水化合物分配与弱光下的存活及不定根形成的关系
Nitrogen- and storage-affected carbohydrate partitioning in high-light-adapted Pelargonium cuttings in relation to survival and adventitious root formation under low light.
作者信息
Druege U, Zerche S, Kadner R
机构信息
Institute of Vegetable and Ornamental Crops Grossbeeren/Erfurt e.V., Kuehnhaeuser Strasse 101, D-99189 Erfurt-Kuehnhausen, Germany.
出版信息
Ann Bot. 2004 Dec;94(6):831-42. doi: 10.1093/aob/mch210. Epub 2004 Oct 27.
BACKGROUND AND AIMS
The aim of this study was to determine the role of nitrogen- and storage-affected carbohydrate availability in rooting of pelargonium cuttings, focusing on the environmental conditions of stock plant cultivation at low latitudes, transport of cuttings, and rooting under the low light that prevails during the winter rooting period in Central European greenhouses.
METHODS
Carbohydrate partitioning in high-light-adapted cuttings of the cultivar 'Isabell' was studied in relation to survival and adventitious root formation under low light. Effects of a graduated supply of mineral nitrogen to stock plants and of cutting storage were examined.
KEY RESULTS
Nitrogen deficiency raised starch levels in excised cuttings, whereas the concentrations of glucose and total sugars in leaves and the basal stem were positively correlated with internal total nitrogen (Nt). Storage reduced starch to trace levels in all leaves, but sugar levels were only reduced in tissues of non-nitrogen deficient cuttings. Sugars accumulated in the leaf lamina of stored cuttings during the rooting period, whereas carbohydrates were simultaneously exhausted in all other cutting parts including the petioles, thereby promoting leaf senescence. The positive correlation between initial Nt and root number disappeared after storage. Irrespectively of storage, higher pre-rooting leaf glucose promoted subsequent sugar accumulation in the basal stem and final root number. The positive relationships between initial sugar levels in the stems with cutting survival and in leaves with root formation under low light were confirmed in a sample survey with 21 cultivars provided from different sources at low latitudes.
CONCLUSIONS
The results indicate that adventitious rooting of pelargonium cuttings can be limited by the initial amount of nitrogen reserves. However, this relationship reveals only small plasticity and is superimposed by a predominant effect of carbohydrate availability that depends on the initial leaf sugar levels, when high-light adaptation and low current light conditions impair net carbon assimilation.
背景与目的
本研究旨在确定氮素和贮藏对碳水化合物有效性在天竺葵插条生根过程中的作用，重点关注低纬度地区母株栽培的环境条件、插条运输以及中欧温室冬季生根期普遍存在的弱光条件下的生根情况。
方法
研究了品种‘伊莎贝尔’高光适应插条在弱光下的碳水化合物分配与存活及不定根形成的关系。考察了向母株逐步供应矿质氮以及插条贮藏的影响。
主要结果
氮素缺乏提高了离体插条中的淀粉水平，而叶片和基部茎中葡萄糖和总糖的浓度与内部总氮（Nt）呈正相关。贮藏使所有叶片中的淀粉降至痕量水平，但仅非氮素缺乏插条组织中的糖水平降低。生根期贮藏插条的叶片中糖分积累，而包括叶柄在内的所有其他插条部位的碳水化合物同时耗尽，从而促进叶片衰老。贮藏后初始Nt与根数之间的正相关消失。无论是否贮藏，生根前较高的叶片葡萄糖含量都促进了基部茎中随后的糖分积累和最终的根数。在一项对来自低纬度不同来源的21个品种的抽样调查中，证实了茎中初始糖水平与插条存活以及叶片中初始糖水平与弱光下根形成之间的正相关关系。
结论
结果表明，天竺葵插条的不定根形成可能受到初始氮储备量的限制。然而，这种关系仅显示出较小的可塑性，并且在高光适应和低光照条件损害净碳同化时，会被取决于初始叶片糖水平的碳水化合物有效性的主要影响所叠加。
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