Growth and physiology of two sunflower cultivars fertilized with sugarcane bagasse ash

ABSTRACT. One way to reduce mineral fertilizers is to use alternative fertilizers instead, such as the byproducts from the food industry. In the present study we evaluated the effects of sugarcane bagasse ash on the physiology, growth, and development of sunflowers (Helianthus annuus L.). We conducted an experiment in a greenhouse using a completely randomized design with two sunflower cultivars (Multissol and Catissol), five sugarcane bagasse ash doses (0.0, 3.125, 4.687, 6.25, and 7.812 mg ha-1), and 5 replicates. At 85 days after planting we determined the plant height; leaf number; stem diameter; internal and external diameter of the flower chapter; leaf area index; shoot dry weight; net assimilation rate; dry mass production rate; relative and absolute growth rate; extravasation of electrolytes; relative water content; photosynthetic pigments (chlorophyll a, b, carotenoids, and the chlorophyll a/b ratio); and soluble carbohydrates, proteins, and proline. The height, number of leaves, and shoot dry mass increased due to the availability of nutrients contained in the ash. The incorporation of ash into the soil increased the photosynthetic activity (chlorophyll a and b) of both sunflower cultivars. The diameter of the stem, leaf area index, and relative growth rate of both sunflower cultivars increased with increasing ash dose. Therefore, the ash can be used as an alternative fertilizer, complementing or replacing mineral fertilizers.

摘要。减少矿物化肥施用的途径之一是采用替代肥料，例如食品工业的副产物。本研究评估了甘蔗渣灰（sugarcane bagasse ash）对向日葵（Helianthus annuus L.）生理、生长及发育的影响。本研究在温室中采用完全随机设计开展试验，设置2个向日葵品种（Multissol与Catissol）、5个甘蔗渣灰施用量梯度（0.0、3.125、4.687、6.25及7.812 mg·ha⁻¹），每组设置5次生物学重复。于播种后85天，测定株高、叶片数、茎粗、花盘内外径、叶面积指数、地上部干重、净同化率、干物质生产速率、相对与绝对生长速率、电解质渗出率、相对含水量、光合色素（叶绿素a、叶绿素b、类胡萝卜素及叶绿素a/b比值）以及可溶性糖、可溶性蛋白与脯氨酸含量。甘蔗渣灰所含养分可提升向日葵株高、叶片数及地上部干重；向土壤施加甘蔗渣灰可提升两个向日葵品种的光合活性（以叶绿素a、b含量表征）；随着施用量提升，两个品种的茎粗、叶面积指数及相对生长速率均显著升高。综上，甘蔗渣灰可作为替代肥料，用于补充乃至替代矿物化肥的施用。