1、Q&A: what are brassinosteroids and how do they act in plants?

A full elucidation of brassinosteroid signalling events and their integration with other signalling pathways will enable brassinosteroid to be applied in agriculture.

2、Brassinosteroid production and signaling differentially control cell division and expansion in the leaf

Brassinosteroid (BR) hormones control plant growth through acting on both cell expansion and division. Here, we examined the role of BRs in leaf growth using the Arabidopsis BR-deficient mutant constitutive photomorphogenesis and dwarfism (cpd).

3、Brassinosteroid action in flowering plants: a Darwinian perspective

These studies led to the discovery of a new class of phytohormones, the brassinosteroids (BRs) that were isolated from rapeseed (Brassica napus) pollen.

4、Brassinosteroid biosynthesis inhibitors

The normal phenotype of inhibitor-treated plants can be recovered by the addition of brassinolide, revealing that inhibitors can be used to complement brassinosteroid-deficient mutants in clarifying the functions of brassinosteroids.

C4 leaf curling – coupling incident light, stomatal and photosynthetic asymmetries

Leaf curling, most often interpreted as a response to water stress (e.g. Heckathorn & DeLucia, 1991), represents a dynamic behavioral response in plants whereby the normal sunlight orientation of the two leaf surfaces may be reversed.

A specific brassinosteroid biosynthesis inhibitor, Brz2001: evaluation of its effects on Arabidopsis, cress, tobacco, and rice

Brassinazole is the only known specific brassinosteroid (BR)-biosynthesis inhibitor, and it has been shown to be useful for elucidating the function of BRs. In the course of a structure-activity relationship study of brassinazole, we found a more specific BR-biosynthesis inhibitor, Brz2001.

Farnesylation mediates brassinosteroid biosynthesis to regulate abscisic acid responses

This result not only directly links farnesylation to brassinosteroid biosynthesis but also suggests new strategies to maintain crop yield under challenging climatic conditions.

Brassinosteroids Control the Proliferation of Leaf Cells of

Restoration of leaf size could not be explained solely on the basis of an increase in individual cell volume, thus suggesting that brassinosteroids play a dual role in regulating cell expansion and proliferation.

Turning on the microscope turret: a new view for the study of brassinosteroid signaling in plant development

Scientists have turned on the microscope lens turret to revisit the pleiotropic phenotypes of the BR mutants at a higher magnification, uncovering novel and specific cellular defects in the plant.

Brassinosteroid

Brassinosteroids (BRs) promote the leaf senescence in concentration dependent manner. BRs-induced senescence is accompanied by the alteration of cell lipid metabolism. BRs increase triacylglecerol and free fatty acid content while decrease galactolipids.

Brassinosteroid is a plant growth regulator that promotes plant growth and development, while improving crop yield and quality. In agricultural production, brassinosteroid is widely used in various vegetables, fruit trees, and flowers.

Spinach, as a common vegetable, often experiences leaf curling, which significantly impacts its yield. This phenomenon is primarily caused by insufficient soil fertility, uneven water supply, or excessively rapid plant growth. To address these issues, brassinosteroid can be applied to restore spinach growth and reduce leaf curling.

I. Mechanism of Brassinosteroid

Brassinosteroid regulates plant growth and development by modulating endogenous hormone levels. Specifically, it promotes the synthesis and secretion of auxins and gibberellins, thereby accelerating plant growth. Additionally, it inhibits the synthesis and activity of ethylene and abscisic acid, slowing growth rates and advancing fruit maturation.

II. Application Guidelines

1. Select the Right Brassinosteroid Formula: Various brassinosteroid products (e.g., brassinosteroid sodium, potassium) are available. Choose based on spinach growth stages:

   • For young seedlings or short-growing spinach, use brassinosteroid sodium.
   • For longer-growing spinach, opt for brassinosteroid potassium.

2. Determine Appropriate Dosage: Dosage depends on growth stage, soil fertility, and climate:

   • Short-growing spinach: 10–50 grams per mu (0.01–0.05 hectares).
   • Long-growing spinach: 50–100 grams per mu.

3. Timing of Application:

   • Optimal: Early growth stage (7–10 days after sowing).
   • Avoid: Late stage (one week before harvest).

4. Application Method:

   • For young/short-growing spinach: Dissolve in water and spray onto leaves.
   • For long-growing spinach: Mix with fertilizers before application.

III. Key Considerations

1. Avoid Overdosage: Excessive use may cause abnormal growth. Stick to recommended dosages.
2. Sequential Application with Fertilizers: Apply other fertilizers before brassinosteroid to ensure efficacy.
3. Interval with Pesticides: Apply pesticides before brassinosteroid to prevent interactions.

Brassinosteroid is an effective tool to mitigate spinach leaf curling and enhance productivity. Proper use—including selecting the right formula, dosage, timing, and application method—can significantly improve yield and quality, delivering better economic benefits for farmers.

Note:

• "Mu" (Chinese unit for area) is retained for agricultural context.
• Technical terms (e.g., "brassinosteroid sodium/potassium") follow standard scientific nomenclature.
• Cultural nuances (e.g., "打" translated as "apply") are adapted for clarity.