Application of Uniconazole Improves Photosynthetic Efficiency of Maize by Enhancing the Antioxidant Defense Mechanism and Delaying Leaf Senescence in Semiarid Regions

Ahmad, Irshad; Kamran, Muhammad; Su, Wennan; Wang, Haiqi; Ali, Shahzad; Bilegjargal, Bayasgalan; Ahmad, Shakeel; Liu, Tiening; Cai, Tommaso; Han, Qingfang

doi:10.1007/s00344-018-9897-5

Cited by 28 publications

(33 citation statements)

References 66 publications

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“…This decrease in chlorophyll and carotenoid contents can be linked with greater lipid peroxidation in the chloroplast membranes during the leaf senescence process, which is in agreement with the previous report [14]. Previously, some studies have reported that the application of plant growth regulators (PGRs) has major effects on improving plant growth and development [5,6,8,27]. Our results also depicted that paclobutrazol application treatments evidently delayed the leaf senescence process and maintained higher chlorophyll contents in maize leaves, compared with the untreated control plants.…”

Section: Discussionsupporting

confidence: 91%

“…The down-regulation of photosynthetic capacity during the senescence has been widely documented in the previous studies [5,7,12,16]. In our present study, the net photosynthetic rate of maize plants declined gradually with the increase in days after silking in all treatments.…”

Section: Discussionsupporting

confidence: 77%

“…The protective role of paclobutrazol on delaying the degradation of chlorophyll and leaf senescence was also verified in Daucus carota [39], wheat [41], rice [42], and pomegranate [43] under unfavorable environmental conditions. In a previous study, exogenous application of uniconazole (with functions similar to paclobutrazol) to maize plants has been reported to maintain higher chlorophyll contents and delayed leaf senescence in maize by upregulating the activities of antioxidants [5].…”

Section: Discussionmentioning

confidence: 99%

“…The precipitation in these regions (250-600 mm each year) during the crop growing season is always insufficient to meet the crop water requirements (500-800 mm) for higher maize productivity [4]. The limited and erratic precipitation accelerates the early onset of leaf senescence and often reduces yields [5].…”

Section: Introductionmentioning

confidence: 99%

“…Although leaf senescence is a natural phenomenon associated with aging, the rate and timing of leaf senescence can be significantly influenced by several environmental perturbations [7,10]. Under semiarid water deficit regions, the senescence often starts before the complete development of all leaf area and progresses at an increased rate during the grain filling period [5]. Leaf senescence causes the disintegration of chlorophyll pigments, inhibition of photosynthesis-related protein and enzymes, thereby reducing the overall photosynthetic capacity [11,12].…”

Section: Introductionmentioning

confidence: 99%

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Paclobutrazol Application Favors Yield Improvement of Maize Under Semiarid Regions by Delaying Leaf Senescence and Regulating Photosynthetic Capacity and Antioxidant System During Grain-Filling Stage

Kamran

Ahmad

et al. 2020

Agronomy

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In the present study, we examined the potential role of paclobutrazol in delaying leaf senescence, in causing changes in the activities of antioxidants, and in the maintenance of photosynthetic activity during the senescence process, and, therefore, on the grain yield of maize under semiarid field conditions. Maize seeds were pretreated with 0 (CK), 200 (PS1), 300 (PS2), and 400 (PS3) mg paclobutrazol L−1. Our results indicated that elevated levels of reactive oxygen species (ROS) and higher accumulation of malondialdehyde (MDA) contents were positively associated with accelerated leaf senescence during the grain-filling periods. The leaf senescence resulted in the disintegration of the photosynthetic pigments and reduced the net photosynthetic rate after silking. However, the resultant ROS burst (O2− and H2O2) was lessened and the leaf senescence and chlorophyll degradation were evidently inhibited in leaves of paclobutrazol-treated maize plants, which was strongly linked with upregulated activities of antioxidant enzymes in treated plants. The enhanced chlorophyll contents and availability of a greater photosynthetic active green leaf area during the grain filling period facilitated the maintenance of higher photosynthetic rate, and light-harvesting efficiency of photosynthesis associated with photosystem II (PSII) resulted in higher kernel number ear−1 and thousand kernel weights, and thus increased the final grain yield. The average maize grain yield was increased by 18.8% to 55.6% in paclobutrazol treatments, compared to untreated control. Among the various paclobutrazol treatments, PS2 (300 mg L−1) treatment showed the most promising effects on enhancing the activities of antioxidative enzymes, delaying leaf senescence and improving the yield of maize. Thus, understanding this effect of paclobutrazol on delaying leaf senescence introduces new possibilities for facilitating yield improvement of maize under semiarid conditions.

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