Department of Biochemistry, State University of Campinas (UNICAMP), Campus Universitário Zeferino Vaz, s/n, Cidade Universitária, CEP 13083-870, Campinas, São Paulo, Brazil; São Paulo State University (UNESP), Institute of Science and Technology, Sorocaba, Avenida Três de Março, 511, CEP 18087-180, Sorocaba, São Paulo, Brazil.
Department of Advanced Materials, Applied Chemistry Research Center (CIQA), Blvd. Enrique Reyna Hermosillo, 140, C.P. 25250, Saltillo, Coahuilla, Mexico.
Carbohydr Polym. 2017 Feb 10;157:1862-1873. doi: 10.1016/j.carbpol.2016.11.073. Epub 2016 Nov 27.
The growth regulator gibberellic acid (GA) has several uses in the field, improving germination, plant development, productivity, and the quality of food. This work describes the development of a nanocarrier system for GA, based on the poly(γ-glutamic acid) (γ-PGA) and chitosan (CS) polymers, Nanoparticles without GA (nano-γPGA/CS-GA) showed colloidal characteristics, with an average size of 117±9nm, PDI of 0.43±0.07, and zeta potential of -29±0.5mV. The encapsulated nanoparticles (nano-γPGA/CS-GA) presented an average size of 134±9nm, PDI of 0.35±0.05, zeta potential of 27.9±0.5mV, and 61% encapsulation. The images of nanoparticles observed by Transmission and scanning electron microscopy (TEM and SEM) showed a spherical shape of the nanoparticles. The system showed sustained release, with 58% release after 48h. Evaluation of thermal properties using DSC and TGA analyses indicated that there was an interaction between the CS and γ-PGA polymers. In tests using Phaseolus vulgaris seeds, nano-γPGA/CS-GA showed high biological activity, enhancing the rate of germination in the first day (50-70%) when compared with free GA (10-16%). Encapsulated GA was also more efficient than the free hormone in the increase of leaf area and the induction of root development (including the formation of lateral roots). These effects were not observed when seeds were treated with nano-γPGA/CS without GA. The results demonstrated the considerable potential of nano-γPGA/CS-GA for use in agriculture.
植物生长调节剂赤霉素（GA）在农业领域有多种用途，可提高种子发芽率、促进植物生长发育、提高作物产量和改善农产品品质。本工作研制了一种基于聚γ-谷氨酸（γ-PGA）和壳聚糖（CS）的 GA 纳米载体系统。未包载 GA 的纳米粒（nano-γPGA/CS-GA）具有胶体特性，平均粒径为 117±9nm，PDI 为 0.43±0.07，ζ电位为-29±0.5mV。包载 GA 的纳米粒（nano-γPGA/CS-GA）平均粒径为 134±9nm，PDI 为 0.35±0.05，ζ电位为 27.9±0.5mV，包封率为 61%。透射电子显微镜（TEM）和扫描电子显微镜（SEM）观察纳米粒的形态为球形。该系统具有缓释特性，48h 时累积释放 58%。差示扫描量热法（DSC）和热重分析（TGA）结果表明 CS 与 γ-PGA 聚合物之间存在相互作用。在菜豆种子试验中，与游离 GA（10-16%）相比，nano-γPGA/CS-GA 显著提高了种子的发芽率（第 1 天 50-70%），表现出较高的生物活性。包封 GA 比游离激素更能有效促进叶片面积的增加和根的发育（包括侧根的形成）。当种子用不含 GA 的 nano-γPGA/CS 处理时，未观察到这些效果。这些结果表明，nano-γPGA/CS-GA 在农业领域具有很大的应用潜力。
