Table I.

Developmental stage of pollen extracted from male cones

Harvest Date (Months after Cone Primordia Appear)Morphological DescriptionStage
  3/23/94 (3.75)Archesporial tissue not differentiated* A2 (Archesporial)
  4/12/94 (4.5)Sporogenous and parietal cells differentiated* SP (Sporogenous parietal)
  4/25/94 (4.75)Meiocytes at late interphaseMe-i (Meiocyte, interphase)
  5/5/94 (5)Meiocytes at late interphase, some early prophaseMe-iep (Meiocytes, interphase early prophase I)
  5/26/94 (5.75)Meiocytes at prophase IMe-p (Meiocytes, prophase I)
  6/6/94 (6.25)Meiocytes at late anaphase I, early telophase IMe-at (Meiocytes, anaphase I telophase I)
  6/29/94 (7)TetradsT1 (Tetrads)
  7/15/94 (7.5)Microspore sacci partially inflatedMi (Microspores)
  3/17/95 (3.5)Archesporial tissue not differentiated* A1 (Archesporial)
  7/3/95 (7)Meiocytes at anaphase IMe-a (Meiocytes, anaphase I)
  7/7/95 (7.25)Meiocytes at anaphase IMe-a′ (Meiocytes, anaphase I)
  8/11/95 (8.25)Microspore sacci inflatedMi-si (Microspores, sacci inflated)
  9/1/95 (9)Mature pollen (two prothallial cells, a generative cell and a tube nucleus)Mp (Mature pollen)
  7/4/96 (7)Meiocytes at telophase I and prophase IIMe-tIpII (Telophase I and prophase II)
  7/16/96 (7.5)TetradsT2 (Tetrads)

The harvest dates (mm/dd/yy) of P. radiata cones used in this study are shown. The approximate time that male cone primordia become visible is based on data collected in previous years (Wang, 1995). Morphological descriptions were determined by microscopic analysis, except the earliest stages, which are marked by asterisks and are based on data collected in previous years by Wang (1995). The abbreviations are based on the description of B. napusanther development (Scott et al., 1991). Numbers are used to distinguish samples at the same stage from different years. The last two samples were used for in situ analysis only. Note that there were clear differences in the rate of development over the 2 years sampled, since the Me-a stage was reached almost 1 month later in 1995 (7/3/95) than in 1994 (6/6/94).