Influence of daily light integral on irrigation needs and flowering of greenhouse-grown geranium and petunia

IF 3.9 2区农林科学 Q1 HORTICULTURE

Scientia Horticulturae Pub Date : 2025-05-01 DOI:10.1016/j.scienta.2025.114188

Anju Chaudhary, Shital Poudyal

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Abstract

Daily light integral (DLI) is a key factor in greenhouse production of geranium and petunia, significantly affecting their growth, flowering and water use. Optimizing greenhouse light intensity can enhance plant growth and flowering while reducing plant water needs. Therefore, the objective of this study was to quantify irrigation water savings achieved by lowering DLI and to determine the optimal DLI that ensure highest plant quality with lowest plant water requirement. Plugs of the geranium and petunia were grown in 3.8 L containers and were maintained at close to 30 % volumetric water content (VWC) using the mass balance method. Four DLI treatments 2.8, 4.9, 6.9, and 17.4 mol.m^-2.d^-1, were maintained using 40 %, 70 %, and 90 % black shade cloth and high-pressure sodium lamp respectively. Photoperiod was maintained at 16-hour light and 8-hour dark periods. The total water use of geranium and petunia was found to have a linear relationship with DLI treatments with an R-squared value of 83.7 % and 92 %, respectively. Reducing DLI from 17.4 to 6.9 mol.m^-2.d^-1 saved 6.86 liters (32 %) of water per plant for geranium and 9.5 liters (36 %) of water per plant for petunias. This saving was largely because of reduced stomatal conductance in plants growing at lower DLI. There was a linear reduction in flower number and plant dry weight as DLI decreased, with the lowest values observed at 2.8 mol·m⁻²·d⁻¹ in both species. However, flowering was delayed only at the lowest DLI (2.8 mol·m⁻²·d⁻¹), while moderate to high DLI levels (4.9 - 17.4 mol·m⁻²·d⁻¹) resulted in similar and earlier flowering times for both geranium and petunia. Interestingly, water use efficiency was highest at a DLI of 4.9 mol·m⁻²·d⁻¹ for geranium and 6.9 mol·m⁻²·d⁻¹ for petunia, indicating that these plants use water more efficiently at moderate DLI. Overall, these results suggest that optimizing DLI to moderate levels can help greenhouse growers significantly reduce water use without compromising flowering time or overall plant marketability.

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日光照积分对天竺葵和矮牵牛灌溉需求和开花的影响

日光照积分（DLI）是天竺葵和矮牵牛温室生产的关键因子，对其生长、开花和水分利用有重要影响。优化温室光照强度可以促进植物生长和开花，同时减少植物对水分的需求。因此，本研究的目的是量化通过降低DLI实现的灌溉节水，并确定以最低的植物需水量确保最高植物质量的最佳DLI。天竺葵和矮牵牛的花塞生长在3.8 L的容器中，并使用质量平衡法保持接近30%的体积含水量（VWC）。4个DLI处理分别为2.8、4.9、6.9和17.4 mol.m-2。D-1，分别用40%、70%、90%的黑色遮光布和高压钠灯维持。光周期维持在光照16小时和黑暗8小时。天竺葵和矮牵牛的总耗水量与DLI处理呈线性关系，r平方值分别为83.7%和92%。将DLI从17.4降低到6.9 mol.m-2。D-1为天竺葵每株节省6.86升（32%）的水，为牵牛花每株节省9.5升（36%）的水。这种节约很大程度上是由于在较低DLI条件下生长的植物气孔导度降低。随着DLI的降低，花的数量和植株的干重呈线性减少，在两个物种中观察到的最低点为2.8 mol·m⁻²·d⁻¹。然而，只有在最低的DLI （2.8 mol·m⁻²·d⁻¹）下开花才会延迟，而中等到高的DLI （4.9 - 17.4 mol·m⁻²·d⁻¹）导致天竺葵和矮牛的开花时间相似且更早。有趣的是，天竺葵和矮牵牛花的水利用效率最高，分别为4.9 mol·m（⁻²·d）和6.9 mol·m（⁻²·d），说明这些植物的水利用效率在中等的DLI下更高。总体而言，这些结果表明，优化DLI至中等水平可以帮助温室种植者在不影响开花时间或整体植物适销性的情况下显着减少用水量。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Scientia Horticulturae 农林科学-园艺

CiteScore

8.60

自引率

4.70%

发文量

796

审稿时长

47 days

期刊介绍： Scientia Horticulturae is an international journal publishing research related to horticultural crops. Articles in the journal deal with open or protected production of vegetables, fruits, edible fungi and ornamentals under temperate, subtropical and tropical conditions. Papers in related areas (biochemistry, micropropagation, soil science, plant breeding, plant physiology, phytopathology, etc.) are considered, if they contain information of direct significance to horticulture. Papers on the technical aspects of horticulture (engineering, crop processing, storage, transport etc.) are accepted for publication only if they relate directly to the living product. In the case of plantation crops, those yielding a product that may be used fresh (e.g. tropical vegetables, citrus, bananas, and other fruits) will be considered, while those papers describing the processing of the product (e.g. rubber, tobacco, and quinine) will not. The scope of the journal includes all horticultural crops but does not include speciality crops such as, medicinal crops or forestry crops, such as bamboo. Basic molecular studies without any direct application in horticulture will not be considered for this journal.