Romero J M, Marañón T
Instituto de Recursos Naturales y Agrobiologia, CSIC, P.O. Box 1052, 41080 Sevilla, Spain.
New Phytol. 1996 Apr;132(4):565-573. doi: 10.1111/j.1469-8137.1996.tb01875.x.
The allocation of biomass and mineral elements (Ka, K, Ca, P, N, Fe, Cu, Mn and Zn) during the ontogenetic cycle of annual sweetclover (Melilotus segetalis (Brot.) Ser.) growing under favourable and saline conditions has been studied. Plants were grown in a glasshouse, in pots with siliceous substrate and watered with Hoagland solution. Half were salinized by adding 170 mol m N Cl (15 dS m ) to the solution. Eleven harvests at 15 d intervals measured the dry weight distribution within the plant and the mineral composition. Allocation relative to biomass (ARB) in each plant organ, both under favourable and salt-stress conditions, was calculated for each mineral element, Biomass and mineral elements were allocated independently within M. segetalis, and the general pattern thanked with age and was affected by salinity. Salt-stressed plants were smaller and invested proportionately more biomass in leaves. Na was accumulated in roots of young plants and excluded from leaves and fruits, whereas K was depleted from roots and accumulated in leaves and fruits. Immobile Ca accumulated in leaves, with age. Phloem-mobile P and X were translocated to flowers and fruits. Fe, Cu and Zn were diluted in leaves and not affected by salt; whereas Mn concentration increased with age and salinity. The switch to reproduction and increased demand for nutrients induced drastic changes in the allocation pattern of mineral elements. Salinity induced a re-allocation of biomass and mineral elements in all plant organs except the reproductive structures, as part of a whole-plant response to minimize salt toxic effects, to achieve osmotic adjustment, to preserve the reproductive output, and to compensate nutrient imbalance.
对一年生草木樨（Melilotus segetalis (Brot.) Ser.）在适宜和盐胁迫条件下生长的个体发育周期中生物量和矿质元素（钾、钾、钙、磷、氮、铁、铜、锰和锌）的分配情况进行了研究。植株种植在温室中，花盆装有硅质基质，并用霍格兰溶液浇灌。一半植株通过向溶液中添加170 mol m N Cl（15 dS m）进行盐处理。每隔15天进行11次收获，测量植株内干重分布和矿质成分。针对每种矿质元素，计算了在适宜和盐胁迫条件下每个植物器官中相对于生物量的分配（ARB）。生物量和矿质元素在草木樨内独立分配，总体模式随年龄变化，并受盐度影响。盐胁迫下的植株较小，且在叶片中投入的生物量比例更大。钠在幼嫩植株的根中积累，叶片和果实中则排除在外，而钾从根中耗尽并在叶片和果实中积累。随着年龄增长，不易移动的钙在叶片中积累。韧皮部可移动的磷和X转运到花和果实中。铁、铜和锌在叶片中被稀释，不受盐的影响；而锰的浓度随年龄和盐度增加。向生殖阶段的转变以及对养分需求的增加导致矿质元素分配模式发生剧烈变化。盐度导致除生殖结构外所有植物器官中生物量和矿质元素的重新分配，这是植株整体反应的一部分，以尽量减少盐的毒害作用、实现渗透调节、维持生殖产量并补偿养分失衡。
