贵州火龙果的气孔特征及其日变化规律

Stomatal Traits and Daily Changing Rule of Hylocereus undatus in Guizhou

【目的】研究火龙果气孔特征及其日变化规律,为贵州火龙果气孔研究、树体水分调控和田间水分管理提供科学支撑。【方法】以贵州火龙果主栽品种紫红龙为试验材料,在电镜下观察火龙果肉质茎及果实表皮气孔特征,分析火龙果气孔日变化和气孔导度变化规律。【结果】火龙果各部位气孔的表面形态及空间格局明显不同,火龙果果实表皮气孔呈下陷形态,为椭圆形;肉质茎表皮气孔呈凸起状,呈近圆形,且2年生肉质茎气孔明显大于1年生。气孔分布密度大小为2年生肉质茎>1年生肉质茎>果实表皮。24 h内,2年生肉质茎气孔在8:00-10:00和16:00-18:00开口较大,1年生肉质茎气孔在8:00-10:00开口较大。火龙果肉质茎气孔导度在2:00-6:30和18:00-23:30较高,高于1年生肉质茎的时段为7:00-17:00。火龙果气孔各指标间具有不同程度的相关性,其中肉质茎气孔内开口横径与气孔开度、形状指数之间具有极显著正相关。【结论】火龙果果实表皮气孔呈凸起状,为椭圆形;肉质茎表皮气孔呈下陷形态,呈近圆形;火龙果气孔在成熟肉质茎表面分布较多,与果实表皮气孔形态差异显著。2年生肉质茎气孔密度大于1年生肉质茎,二者气孔开放程度和开闭规律大体一致,气孔开度与气孔内开口横径、面积、周长、气孔开放率间存在密切联系。

【Objective】The stomatal traits and daily changing rule of pitaya is studied,which provides scientific basis for stomatal study of pitaya,regulation of water in plants and management of water in field of Guihzou.【Method】Using the main cultivar of Guizhou pitaya,Hylocereus undatus cv.Zihonglong,as test material,the stomatal traits of fleshy stem and fruit epidermis of H.undatus are observed with electron microscope.The changing rule of daily stomatal variation and stomatal conductance are analyzed.【Result】There are obvious differences in stomatal surface morphology and spatial pattern of different stems.The stomas in fruit epidermis are sunren and appear as oval.The stomas in fleshy stem are sunken and appear as nearly circular,and the stomas in fleshy stem of two-year-old H.undatus are significantly bigger than that of one-year-old pitaya.Stomatal density in different stems shows as the fleshy stem of two-year-old>the fleshy stem of one-year-old>fruit epidermis.The stomas in fleshy stem of two-year-old H.undatus are bigger at 8:00-10:00 and 16:00-18:00,while the stomas in fleshy stem of one-year-old H.undatus are bigger at 8:00-10:00.The stomatal conductance are higher at 2:00-6:30 and 18:00-23:30,and the stomatal conductance of two-year-old pitaya is higher than that of one-year-old pitaya at 7:00-17:00.The indexes of stomatal conductance of H.undatus shows correlation with different level.Among these indexes,the transverse diameter of stomatal aperture in fleshy stem is significantly positive related to the opening degree and shape index.【Conclusion】The stomas in fruit epidermis shows as convex and oval,while stomas in fleshy stem shows as sunken and nearly circular.There are more stomas on the surface of mature fleshy stem of H.undatus,whose shapes are obvious different from stomas in fruit epidermis.The stomatal density of two-year-old pitaya is bigger than that of one-year-old pitaya.The opening degree of stomas is consistent with closure law,and the opening degree is closely related to the transverse diameter stomatal aperture,area,perimeter and open rate.