Growth, relative chlorophyll content and concentration of inorganic solutes in sunflowers plants supplemented with marine macroalgae organic residue

ABSTRACT One effect of the tidal dynamics is the accumulation during the low tide of large volumes of macroalgae, named “arribadas algae”. The objective of this work was to analyze the effects of using arribada alga e organic residues (AAOR) on the initial growth of sunflower plants, where the following were evaluated: plant growth, relative chlorophyll content and inorganic solids content (Na, K, Cl and NO3). The algae were collected on Praia do Pacheco in Caucaia, state of Ceará, Brazil, washed in running water and placed to dry in the sun for seven days, then dried in a forced circulation oven at 80 ºC and crushed. The sunflower seeds were sown in 5L plastic buckets, containing: 1) 100% (in volume) of sand; 2) sand + 100% of nitrogen recommendation - NR in commercial fertilizer (80kg of N.ha-1); 3) sand + 50% of the NR in macroalgae; 4) sand + 100% of NR in macroalgae; and 5) sand + 150% of the NR in macroalgae. The use of AAORimproved the growth of the analyzed variables in relation to the plants grown in substrate with sand or sand + fertilizer. The best results were observed at 50% of the NR in AAOR. The addition of increasing concentrations of AAOR allowed a greater accumulation of beneficial ions such as K and NO3 while no significant differences were observed for toxic ions such as Na and Cl in relation to plants supplemented with fertilizer or sand. The use of AAOR in substrates can be an alternative to fertilizers in plant cultivation since it reduces production costs besides being a sustainable destination.

摘要：潮汐动力过程的一项典型效应是，退潮阶段会堆积大量大型藻类，这类藻类被称为"arribadas藻"（arribadas algae）。本研究旨在分析"arribadas藻"有机残体（arribada algae organic residues，缩写为AAOR）对向日葵植株初期生长的影响，评估指标涵盖植株生长性状、相对叶绿素含量以及钠（Na）、钾（K）、氯（Cl）、硝酸根（NO₃⁻）四类无机固形物的含量。实验所用藻类采集自巴西塞阿拉州考卡亚市的帕谢科海滩（Praia do Pacheco），经流水冲洗后置于阳光下晾晒7天，随后在80℃的鼓风干燥箱中烘干并粉碎。向日葵种子播种于容积为5L的塑料桶中，栽培基质共设置5组处理：1）100%体积的纯沙；2）沙+100%商品肥料推荐施氮量（nitrogen recommendation，缩写为NR，即80kg N·ha⁻¹）；3）沙+50%推荐施氮量的大型藻类肥；4）沙+100%推荐施氮量的大型藻类肥；5）沙+150%推荐施氮量的大型藻类肥。实验结果表明，与纯沙基质或沙+化肥基质中生长的植株相比，施用AAOR可显著提升各检测指标对应的植株生长表现，其中以50%推荐施氮量的AAOR处理效果最优。提高AAOR施用浓度可促进钾、硝酸根等有益离子的积累，而钠、氯等有毒离子的含量与化肥组或纯沙组相比无显著差异。在栽培基质中施用AAOR可作为植物栽培中化肥的替代方案，不仅能够降低生产成本，同时还为藻类有机残体提供了一条可持续的处置路径。