Optimization of In Vitro Germination, Viability Tests and Storage of Paeonia ostii Pollen

Abstract

Paeonia ostii is an important woody oil crop mainly cross-pollinated. However, the low yield has become an important factor restricting the industrial development of P. ostii. Cross-pollination has become one of the important measures to increase the seed yield. Therefore, conservation of pollen with high vitality is crucial to ensure successful pollination of P. ostii. In this study, we found an effective methodological system to assess the viability, ability to germinate, and optimal storage conditions of P. ostii pollen grains. The optimal medium in vitro was 50 g/L sucrose, 100 mg/L boric acid, 50 g/L PEG6000, 100 mg/L potassium nitrate, 300 mg/L calcium nitrate, and 200 mg/L magnesium sulfate at pH 5.4. Optimal germination condition in vitro was achieved at 25 °C for 120 min, allowing easy observation of the germination percentage and length of the pollen tubes. In addition, the viability of pollen grains was assessed by comparing nine staining methods. Among them, MTT, TTC, benzidine-H2O2, and FDA were effective to distinguish between viable and non-viable pollen, and the results of the FDA staining method were similar to the pollen germination percentage in vitro. After evaluation of pollen storage, thawing and rehydration experiments showed that thawing at 4 °C for 30 min and rehydration at 25 °C for 30 min increased the germination percentage of pollen grains stored at low temperatures. The low-temperature storage experiments showed that 4 °C was suitable for short-term storage of P. ostii pollen grains, while −80 °C was suitable for long-term storage. This is the first report on the in vitro germination, viability tests, and storage of P. ostii pollen grains, which will provide useful information for P. ostii germplasm conservation and artificial pollination.

Simple cryopreservation protocol for Luffa pollen: enhancing breeding efficiency

“…Staining tests are widely used for determining pollen viability because they are quick and easy ( Huang et al., 2004 ; Li et al., 2023 ). The assessment of pollen viability by staining tests (KI and AC) in the present study revealed that >95% pollen viability was observed in all species, with an overestimation of 6%–10% in AC staining and 7%–10% in KI staining in comparison to in vitro pollen germination ( Figure 4 ).…”

Biological characteristics of flowers and examination of pollen viability at different developmental stages of Epimedium sagittatum( Sieb. et Zucc. )Maxim

“…Studies have found that the size of pollen viability directly affects the pollination and fertilization processes of plants, which is closely related to the yield and quality of plant seeds (Bai et al,2023). Testing the viability of Epimedium sagittatum pollen at different owering stages before pollination can understand the viability, development and physiological characteristics of Epimedium sagittatum pollen, and grasp the morphology of sterile pollen, providing a theoretical basis for arti cial breeding (Li et al,2023;Xu et al,2012). Therefore, researching the viability and germination characteristics of Epimedium sagittatum pollen is very necessary to improve pollination breeding e ciency and reasonably carry out breeding to increase seed germination rate and obtain high-quality Epimedium sagittatum seeds.…”