Film antitranspirant (AT) forms a physical layer to block stomata on the leaf surface and thus improve plant water status under drought. There is little understanding of how leaf coverage relates to the physiological mechanism, so a reliable method of evaluating AT spray deposition is needed. Titanium dioxide (TiO₂) is widely applied to heighten the whiteness, brightness and opacity of materials, which can be potentially used as an inert marker to visualize AT deposited on leaves. This study aimed to evaluate the effect of TiO₂ on the spray characteristics and coverage of film AT (a.i. di-1-p-menthene) on water-sensitive papers (WSP) and its subsequent use to explore the dose-response relationship between this AT and leaf coverage. Spray characteristics when applied through standard 110° flat fan nozzles were assessed using a droplet analyzer and coverage was measured using image analysis of deposition on water sensitive paper (WSP) and oilseed rape leaves. There was no significant difference observed with TiO₂ added to film AT and water in droplet size spectra. Spray coverage averaged 46.8% and 57.3% respectively when WSP were positioned at 70 cm and 50 cm below nozzles. Adding TiO₂ to AT solutions with different dose rates had no significant effects on WSP spray coverage at either nozzle height. Leaf coverage was positively correlated with the dose rates of AT at the distance of 50 cm from nozzles to the canopy. Overall, results suggest that TiO₂ did not affect droplet size spectra or deposition on WSP of the AT when applied through a flat fan nozzle. Therefore, TiO₂ can be effective as a method to estimate the leaf coverage of film AT on rapeseed for use in future physiological studies.

防潮膜（AT）形成物理层以阻止叶片表面的气孔，从而改善干旱条件下的植物水分状况。人们对叶片覆盖率与生理机制之间的关系了解甚少，因此需要一种可靠的方法来评估AT喷雾沉积。二氧化钛（TiO ₂）被广泛应用于增强材料的白度，亮度和不透明度，可以潜在地用作惰性标记，以可视化沉积在叶片上的AT。这项研究旨在评估TiO ₂对薄膜AT（ai di-1- p-水敏纸（WSP）上的薄荷烯酮及其后续用途，以探索该AT与叶片覆盖率之间的剂量反应关系。通过液滴分析仪评估通过标准110°平扇形喷嘴喷洒时的喷雾特性，并使用对水敏纸（WSP）和油菜籽叶上的沉积物进行图像分析来测量覆盖率。在液滴尺寸光谱中，将TiO ₂加入膜AT和水中没有观察到显着差异。当WSP位于喷嘴下方70 cm和50 cm处时，喷雾覆盖率分别平均为46.8％和57.3％。添加TiO ₂在两种喷嘴高度下，不同剂量率的AT溶液对WSP喷雾覆盖率均无显着影响。从喷嘴到树冠的距离为50 cm，叶片覆盖率与AT的剂量率呈正相关。总体而言，结果表明，当通过扁平风扇喷嘴施用时，TiO ₂不会影响液滴的尺寸谱或AT的WSP上的沉积。因此，TiO ₂可以作为一种有效的方法来估计油菜籽膜AT的叶片覆盖率，以用于未来的生理研究。