Modification of Root-Shoot-Ratio of Sunflower (Helianthus annuus, L.) by Nitrogen Supply and a Triazole-Type Plant Growth Regulator

Salt stress negatively affects maize growth and yield. Application of plant growth regulator is an effective way to improve crop salt tolerance, therefore reducing yield loss by salt stress. Here, we used a novel plant growth regulator B2, which is a functional analogue of ABA. With the aim to determine whether B2 alleviates salt stress on maize, we studied its function under hydroponic conditions. When the second leaf was fully developed, it was pretreated with 100 µM ABA, 0.01 µM B2, 0.1 µM B2, and 1 µM B2, independently. After 5 days treatment, NaCl was added into the nutrient solution for salt stress. Our results showed that B2 could enhance salt tolerance in maize, especially when the concentration was 1.0 µMol·L−1. Exogenous application of B2 significantly enhanced root growth, and the root/shoot ratio increased by 7.6% after 6 days treatment under salt stress. Compared with control, the ABA level also decreased by 31% after 6 days, which might have resulted in the root development. What is more, B2 maintained higher photosynthetic capacity in maize leaves under salt stress conditions and increased the activity of antioxidant enzymes and decreased the generation rate of reactive oxygen species by 16.48%. On the other hand, B2 can enhance its water absorption ability by increasing the expression of aquaporin genes ZmPIP1-1 and ZmPIP1-5. In conclusion, the novel plant growth regulator B2 can effectively improve the salt tolerance in maize.

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Nitrogen supply associated with the application of trinexapac-ethyl in upland rice irrigated by sprinkler

Semina Ciências Agrárias ◽

10.5433/1679-0359.2019v40n5supl1p2137 ◽

2019 ◽

Vol 40 (5Supl1) ◽

pp. 2137

Author(s):

Igor Balbi Guirão Peron ◽

José Roberto Portugal ◽

Orivaldo Arf ◽

Ricardo Antônio Ferreira Rodrigues ◽

Douglas de Castilho Gitti

Keyword(s):

Plant Growth ◽

Plant Height ◽

Growth Regulator ◽

Plant Growth Regulator ◽

Foliar Application ◽

Upland Rice ◽

Sprinkler System ◽

Nitrogen Supply ◽

Differentiation Stage ◽

Milling Yield

The lodging of rice plants significantly increases the losses of this crop. Lodging is caused by the inadequate management of water and fertilizers, particularly nitrogenous fertilizers. The use of growth regulators causes a reduction in plant height and consequently lodging, and may reduce harvest losses. The objective of this study was to evaluate nitrogen (N) doses with and without application of plant growth regulator in upland rice irrigated by a sprinkler system. The experimental design consisted of randomized blocks arranged in a 4 × 2 factorial design with four replicates. The treatments consisted of four N doses (0, 40, 80, and 120 kg ha-1) combined with the presence or absence of foliar application of a plant growth regulator. The application of 150 g ha-1 of trinexapac-ethyl at the flower differentiation stage reduced plant height and lodging. In addition, this treatment promoted increased 100-grain mass. The use of N doses in topdressing increased plant heights and grain yield. The plant growth regulator did not interfere with the milling yield of upland rice. Nitrogen fertilization in the topdressing did not interfere with the milling yield of upland rice irrigated by a sprinkler system.

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