Paclobutrazol is a highly active plant growth retarder and spectral fungicide widely used at present. Its main physiological effects are delaying plant growth, inhibiting stem elongation, shortening internode, promoting plant tillering, improving plant lodging resistance and stress resistance, and increasing yield. The effect of paclobutrazol on maize seed germination and seedling growth was studied in this paper.

1 Materials and methods

1.1 Test varieties

Xin'an No. 5

1.2 Drug source

The technical products of paclobutrazol produced by Anyang Quanfeng Pesticide Chemical Co., Ltd., with the content of 95% and 84% respectively, are ground into 25% paclobutrazol suspension.

1.3 Test setup

In this test, 5 treatments were set for each content of technical drug, and each treatment had 3 replicates.

1.4 Test conditions

Soak the seeds for 12 hours at room temperature, dry them in the shade, and then plant them in a nutrient bowl, grow under natural conditions, and keep the soil moist.

1.5 Measurement items and methods

Record the germination number of maize seeds on the 14th day, and measure the plant height, root length and stem diameter of the sprouted plants on the 9th day.

2 Results and analysis

2.1 Effect of paclobutrazol on maize seed germination

The results showed that the germination rate of corn was improved after soaking seeds with paclobutrazol (Table 1), and sample 1 represented 25% suspension agent with 95% content of paclobutrazol; Sample 2 represents a 25% suspension agent of 84% paclobutrazol technical, the same below.

Table 1 Effect of paclobutrazol on seed germination

2.2 Effect of paclobutrazol on maize seedling growth

After soaking seeds with paclobutrazol, the plant height is inhibited, the stem is thickened, the root length is increased, the leaf color is dark green, and the leaf thickness is increased (see Fig. 1-4).

It can be seen from Table 2 that paclobutrazol significantly inhibited the growth of maize seedlings. Measured on the 9th day after sowing, with the increase of paclobutrazol concentration, sample 1 reduced the seedling height by 56%~65%; Sample 2 reduced the seedling height by 53%~63%, the root length and stem diameter were higher than those of the control group, and the stem diameter increased significantly when the concentration was 400mg/L; When the concentration of sample 1 is 400mg/L, the root length increases significantly; when the concentration of sample 2 is 800mg/L, the root length increases significantly.

Table 2 Effect of paclobutrazol on maize seedlings

3 Discussion

The experiment showed that paclobutrazol could improve the germination rate of corn, reduce the plant height and increase the stem diameter. This may be related to the fact that paclobutrazol reduces the content of GA and IAA in plants and promotes the rate of ethylene release. According to the research of Zhang Yuanhai and others, the rice treated with paclobutrazol corresponds to the reduction of plant height. The average content of GA is 8.4% of the control, IAA is 47.5% of the control, and the release rate of ethylene is 137.4% of the control. Paclobutrazol can obviously promote the development of root system, which is beneficial to the absorption of water and mineral substances, which is beneficial to the cultivation of strong seedlings of maize.

Figure 1 95% TC

Figure 2 84% TC

Figure 3 95% TC

Figure 4 84% TCv

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