ObjectiveThe purpose of this study was to investigate the effects of plant growth retardants on the leaf anatomy and non-structural carbohydrates of chestnut saplings, and the effects of leaf anatomical changes on non-structural carbohydrate content,in order to provide a theoretical basis for the application of plant growth retardants in the regulation of chestnut growth.
MethodIn this experiment, chestnut (Castanea) cultivar ‘Yanshanzaofeng’ was taken as the experimental material, and exposed to different concentrations of paclobutrazol, chlormequat and uniconazole,then the anatomy and non-structural carbohydrates of the leaf were analysed.
Result(1) Paclobutrazol, chlormequat and uniconazole could increase the thickness of the cuticle of chestnut leaves. The maximum thickness of the upper cuticle was 5.46 μm treated with 90 mg/L uniconazole, and the thickness of the lower cuticle was 1.76 μm treated with 60 mg/L uniconazole; (2) except for treatment with 60 mg/L uniconazole, the other treatments could increase the thickness of leaves and palisade tissue. The most significant effects of leaf and palisade tissue thickness were 100 mg/L paclobutrazol treatments; (3) three kinds of retardants could increase the palisade to sponge tissue ratio, it was up to 1.52, which was treated with 90 mg/L uniconazole; (4) except 60 mg/L uniconazole treatment, the other treatments could effectively increase the non-structural carbohydrate content of chestnut leaves, the increase of non-structural carbohydrate content was most significant at 120 days after treatment.
ConclusionSpraying paclobutrazol, chlormequat and uniconazole on the leaf surface in the period of chestnut flower buds could affect the anatomy of chestnut leaves, thereby enhancing the photosynthesis of chestnut,and the best treatment was 100 mg/L paclobutrazol. Paclobutrazol, chlormequat and uniconazole could effectively increase the non-structural carbohydrates content of chestnut leaves, and 60–90 mg/L of uniconazole was the best treatment. Due to the application of retardants, the leaf anatomy changed the photosynthesis of the leaves, which increased the assimilation, and it made the non-structural carbohydrate content of the leaves increase.