Ultrastructural changes of pistachio (Pistacia vera L.) mature seeds and pollen in relation to desiccation

作者：Bahramabadi Elaheh Zamani^*; Jonoubi Parisa; Rezanejad Farkhondeh

来源：Trees - Structure and Function, 2018, 32(1): 29-39.

DOI：10.1007/s00468-017-1606-7

• Orthodox
• Pistachio
• Pollen
• Recalcitrant
• Seed
• Ultrastructure

Pistachio seeds and pollen have desiccation tolerance and desiccation sensitivity ultrastructural characters at maturation, respectively. Seed cells filled with storage matter remain integrated, whereas some pollen show cell rupture.
Maturation drying is a common trait of seeds and pollen. Orthodox seeds and pollen become tolerant to desiccation at maturation and remain their germinability in an inactive dry state for a period of time, whereas recalcitrant ones remain sensitive and must germinate immediately after maturation. This study investigated the moisture content, germinability and ultrastructure of pistachio (Pistacia vera L.) mature seeds and pollen in fresh and 24 h-desiccated states using microscopy methods. Seeds lost 90.5% water and remained 100% germinable demonstrating their orthodoxy. Fresh and desiccated cells of both cotyledon and ground meristem of root tip, mostly contained lipid and protein reserves. Large autophagic vacuoles in fresh cells contained autophagic bodies digesting organelles related to active metabolism and became converted to protein storage vacuoles at desiccated state. In ground meristem of root tip, most lipid bodies were tiered adjacent to plasma membrane probably with a secretory function and the cell walls were waved at desiccated state. Pollen lost 46.7% water along with 93% germinability by desiccation demonstrating its recalcitrance. After desiccation, 1.8% of pollen grains displayed intine degeneration, vegetative cell plasmolysis and detachment from intine, lobed vegetative cell nucleus, great vacuolation along with organelles destruction in both vegetative and generative cells and finally cell rupture. However, most pollen displayed normal structure indicating the recalcitrance behavior of pistachio pollen is not mainly related to cell structural damages but, lack of germinability through molecular damages that should be studied in details.

• 出版日期2018-2