Common Diseases in the Acclimatization and Transplantation of Tissue-Cultured Seedlings and Specific Control Measures:

1. Vitrification
   Symptoms: Deformed plant tissues, weakened organ function, difficulty in surviving transplantation.
   Preventive measures:

   • Control temperature to avoid extreme high or low temperatures that could affect the seedlings.
   • Extend light exposure to promote normal photosynthesis in the seedlings.
   • Use breathable sealing membranes to improve ventilation and prevent excessive moisture buildup.
   • Adjust the concentration of agar and reasonably control the hardness of the medium to prevent vitrification caused by excess moisture.

2. Root-Knot Nematode Disease
   Symptoms: Galls form on roots, impairing absorption, slowing plant growth, causing yellowing and wilting of leaves.
   Control measures:

   • Immediately remove and burn affected seedlings to prevent the spread of disease.
   • Treat infected soil with solarization or soil fumigation using nematicides like ethoprophos. Drench roots and cover with plastic film to maintain high temperatures (35–40°C) and kill nematodes.
   • Perform root treatment around 20 days after transplantation to prevent disease transmission.

3. Browning
   Symptoms: Browning of plant tissues, affecting normal growth, often caused by improper culture conditions.
   Preventive measures:

   • Optimize culture conditions, including regulating light, temperature, and humidity to ensure a suitable environment.
   • Transfer culture materials promptly to prevent browning due to prolonged exposure to the medium.
   • Regularly subculture varieties prone to browning to maintain the vitality of the culture material.

4. Contamination
   Symptoms: Bacterial or fungal contamination preventing normal growth of tissue-cultured seedlings.
   Control measures:

   • Maintain cleanliness in the culture room and regularly clean and disinfect equipment and tools.
   • Strictly screen base seedlings to ensure healthy, disease-free source materials.
   • Sterilize culture media and inoculation tools thoroughly, and use sterile procedures to avoid cross-contamination during the inoculation process.
   • Replace the pre-filter of the clean bench every six months to ensure air cleanliness in the work environment.

Conclusion:
The occurrence of different diseases is closely related to the culture conditions, transplantation environment, and management practices of tissue-cultured seedlings. Key preventive measures include:

• Optimizing culture conditions: light, temperature, humidity, and composition of the medium.
• Strict aseptic procedures: maintaining cleanliness, thorough tool disinfection, and adhering to operational standards.
• Early monitoring and timely intervention: Regularly check the growth status of seedlings, and take appropriate measures when problems are detected.

Through the above comprehensive management practices, it is possible to effectively reduce the occurrence of diseases and ensure the successful acclimatization and transplantation of tissue-cultured seedlings.