Reproductive Ecology of Male and Female Strobili and Mating System in Two Different Populations of Pinus roxburghii

Table 2

Reproductive phenology of Pinus roxburghii.

Observed variables	Lower altitude (900 m asl)				Higher altitude (1900 m asl)
	1998	1999	2000	2001	1998	1999	2000	2001
Date of Pollen cone bud initiation	January 16th	January 13th	January 20th	January 10th	February 2nd	January 30th	February 6th	January 30th
Date of Pollen cone maturation	February 12th	February 10th	February 14th	February 8th	February 27th	February 24th	February 27th	February 26th
Date of Pollen cone blooming	February 23rd	February 18th	February 26th	February 21st	March 13th	March 04th	March 10th	March 6th
Anthesis cycle of pollen cone	3 days	2 days	3 days	2.5 days	7 days	5 days	6 days	6 days
Peak period of anthesis within a day	1200 and 1400 h	1200 and 1400 h	1200 and 1400 h	1200 and 1400 h	1200 and 1400 h	1200 and 1400 h	1200 and 1400 h	1200 and 1400 h
Min.-Max. temperature (°C) within the study period during anthesis	7.3−18.2	8.5–19.3	7.0–18.5	7.6–20.0	7.2–14.3	7.8–17.2	6.6–17.0	7.4–18.0
Min.-Max. R. H. (%) within the study period during anthesis	64–82	62–80	60–80	60–80	70–86	68–84	70–85	65–85
Min.-Max. wind speed (m/s) within the study period during pollen grains in the air were sampled	0.8–3.8	0.6–2.4	0.4–2.8	0.8–3.0	0.8–3.0	0.6–3.5	0.6–3.2	0.8–3.5
Date of ovulate cone initiation	February 22nd	February 18th	February 24th	February 21st	March 10th	March 04th	March 08th	March 05th
Ovulate cone receptivity period	4 days (Feb. 27th–March 2nd)	3 days (Feb. 23rd–Feb. 25th)	3 days (Feb. 27th–Mar. 1st)	3 days (Feb. 26th– Feb. 28th)	5 days (Mar 13th– March 17th)	5 days (Mar. 09th– March 13th)	4 days (Mar. 12th–March 15th)	4 days (Mar. 10th–March 13th)