Plant roots are an important component of the rhizosphere, playing a critical role in transporting water and nutrients into the soil. Furthermore, aboveground biomass production relies heavily on plant roots. Root growth and distribution in the soil determine the crop’s ability to absorb nutrients and water. Improving plant root systems allows them to better absorb water, nutrients, and minerals from the soil. Approximately 49% of the yield increase is attributed to improved crop management practices, and the remaining 51% is due to genetic improvement. Plant growth regulators that reduce lodging and increase grain weight are key to increasing yield. Lodging reduces water and nutrient transport and photosynthesis, resulting in lower corn yields. Lodging rates also negatively impact ear kernel count and grain weight, reducing yield quality. Corn lodging occurs predominantly at the third basal node during the grain filling stage, as this is when carbohydrates from the stalk are transported to the ear. Premature senescence and lodging of corn are directly related to root growth. Root system analysis is an important factor in increasing yield and reducing lodging in dryland agricultural systems.13
Adequate soil moisture can significantly increase the root dry matter density per unit area. Compared with traditional fertilizer application methods, the application of plant growth regulators (PPRs) can enhance the uptake of water and nutrients from the soil by roots. Root pressure is an indicator of root sap flow and secretion. Root secretion depends on its intensity, while root activity varies with soil moisture conditions, crop type, and growing season. In the field, it is difficult to accurately understand root behavior, while root secretion can be used to predict root behavior and nutrient and water uptake. Root lodging is influenced by many factors, including root number, root diameter, and growth direction. Lignin content is a key component of stems and has a significant effect on the lodging rate of stems. Ethephon is an effective growth regulator that can reduce the risk of lodging. Ethephon can be used to reduce corn root height, increase mechanical strength, and improve root adhesion. Ethephon and chlormequat chloride can effectively enhance lodging resistance and endogenous hormonal signaling. DA-6 significantly reduced lodging rate, panicle number, and plant height, and improved stem penetration. Therefore, addressing lodging problems in agricultural crops is key to achieving stable and high yields.
We hypothesize that in semi-arid regions, combining various tillage practices with plant growth regulators can reduce the risk of corn lodging and increase yield. To test this hypothesis, this experiment measured the effects of various tillage practices combined with plant growth regulators on the physicochemical properties of corn stalks, root morphology, molecular structure of vascular bundles, endogenous hormone content in root sap, and yield. The goal of this study is to provide a theoretical basis for improving corn lodging resistance and yield in semi-arid regions. The use of plant growth regulators is beneficial for agricultural production management.
Monthly distribution of precipitation and temperature at experimental plots during the 2021 and 2022 corn growing seasons.
Using this model, the average root growth rate (Ć) during the growing season can be calculated using the following formula:
At the panicle formation stage, five plants were selected from each plot, and the root system was removed from the center of the plant, with the distance between rows being half the width and length of the plant. After rinsing the roots, the surface moisture was dried with filter paper, and the number of root layers was counted. Fresh coltsfoot roots were dried at 80°C to constant weight, after which their dry weight was measured. Endogenous hormone flux was determined using an enzyme-linked immunosorbent assay (ELISA) (Wang et al. ).
The effect of different tillage methods in combination with plant growth regulators on root density at a depth of 0–100 cm in 2022. Vertical lines represent the standard error of the mean (SEM) (n = 3). Lowercase letters indicate significant differences at a significance level of P ≤ 0.05 (LSD test).
The effect of different tillage methods in combination with plant growth regulators on root mass density at 0–100 cm depth in 2022. Vertical lines represent the standard error of the mean (SEM) (n = 3). Lowercase letters indicate significant differences at a significance level of P ≤ 0.05 (LSD test).
Numerous tillage treatments combined with plant growth regulators significantly affected the morphological characteristics of improved roots at the heading stage (Table 6). In the EYD and EYR treatments, the diameter, volume, inclination angle, and dry weight of improved roots increased, with rotary tillage combined with the Jindel and Yuhuangjin plant growth regulators showing the best effect. In both years of the study, the use of plant growth regulators increased the diameter, volume, inclination angle, and dry weight of improved roots. Compared with the control treatment, the number of improved root layers in the EYD, EYR, and EYB treatments increased significantly in 2021. However, no significant differences were observed between treatments in 2022.
In all tillage treatments, the lodging rate (EYD), lodging ratio (EYR), lodging index (EH), lodging coefficient (EHC), and lodging coefficient (CG) of corn in 2021 and 2022 were significantly higher than in other years (Table 8). Various tillage treatments significantly improved the lodging coefficient and lodging index, while the application of Jindel + Yuhuangjin plant growth regulator increased the lodging coefficient. In 2016, there were no significant differences in the lodging index, lodging coefficient, and lodging coefficient between the two study years. The correlation between the lodging index, lodging coefficient, and lodging coefficient and other tillage treatments significantly increased in the tillage treatments for lodging coefficient and lodging index, resulting in improved lodging performance.
Compared with other cultivation methods, plant growth regulators can regulate crop growth according to production needs , control plant morphology, and increase lignin content, plant hormone levels, and yield . It is well known that plant growth regulators have the advantage of low input costs . Currently, compared with the control treatment, EYD treatment shows higher lignin content in the third internode. The lignin content is significantly positively correlated with the activity of endogenous hormonal signals, which is consistent with the results of previous studies. The improved lodging resistance is mainly attributed to the increase in the contents of lignin, cellulose, carbohydrates, and anatomical structural factors such as bark thickness, the number of vascular bundles, and the degree of lignification. In this study, it was found that the bark thickness and the number of vascular bundles of maize increased with EYD treatment. In the EYD treatment, small vascular bundles were densely packed, and large vascular bundles were well developed. Plant vascular bundles are also important for the transport of water and nutrients.45 The permeability of maize vascular tissue is positively correlated with the number of vascular bundles.42 In the EYD treatment, compared with the control treatment, SLR decreased by 97%, RLR by 65%, and TLR by 74%.
The main interaction pathways were root sap exudation and endogenous hormone levels. In the EYD treatment, the root sap exudation rate was significantly higher at all growth stages than in all other treatments. There were no significant differences in root sap exudation rates between the ER and EYR treatments, or between the YB and EYB treatments at any growth stage. Furthermore, at 25 and 125 days after sowing, the root sap exudation rate was significantly higher in the YD and EYD treatments than in all other treatments. Tillage method significantly influenced the rate of root sap exudation. Rototillage significantly increased root sap exudation, which significantly improved the nutrient uptake capacity of roots and yield. 46 At the V7 and grain filling stages, NO − and NH 4+ transport was significantly higher in the EYD treatment than in any other treatment. Ionic transport in root sap was also significantly higher in the EYD treatment than in any other treatment at different growth stages. Plant vascular bundles are also crucial for the transport of water, nutrients, and photosynthesis. 34 Transport tissues and vascular bundles are positively correlated in maize plants.38
Improved stem strength and root morphology enhanced the plant’s ability to transport water, nutrients, and photosynthesize, which positively impacted the seed filling stage. When rotary tillage was combined with plant growth regulator (PGR) spraying using Kindle + Yuhuanghuang, the EYD and EYR treatments maximized root parameters. In 2021, the number of root layers increased significantly in the EYD, EYR, and EYB treatments, but the difference was insignificant in 2022. Plant growth regulators can improve root nutrient uptake by improving root morphology. The relative abundances of various hormones, rather than the absolute abundances of specific hormones, determine physiological effects.
The application of plant growth regulators during tillage can significantly reduce the risk of lodging, primarily by increasing stem mechanical strength. Our results show that the application of Jindel + Yuhuangjin in combination with rotary tillage significantly reduced the lodging rate, improved root distribution and dry mass, and enhanced stem microstructure, lignin content, buttress root morphology, and corn yield. The EYD treatment significantly promoted root growth, increased lignin content, and stem mechanical strength, while significantly reducing the lodging rate. Furthermore, the NO3- and NH4+ contents were significantly higher in the EYD treatment than in the ED and YD treatments. The transfer rates of Zn, Fe, K, Mg, P, and Ca reached their maximum values in the EYD and EYR treatments. The EYD treatment increased root inclination angle, dry mass volume, and buttress root diameter. Compared with the ED and YD treatments, the Ć, cm, and Wmax values for TRDW, ARD, and TRL significantly increased with the EYD and EYR treatments. Increased levels of RLD, ARD, and RDWD with the EYD treatment promote root development, improve soil moisture, and enhance nutrient uptake, thereby significantly enhancing lodging resistance and representing an effective method for mitigating crop risks in semi-arid regions. The results demonstrate that these technologies are promising tools for farmers in semi-arid regions, enabling them to maintain high corn yields while reducing lodging losses. However, further research is needed on the use of plant growth regulators in integrated farming and their control mechanisms in different corn varieties.
Post time: Feb-02-2026