Characteristics of cones and seeds of Pinus sibirica Du Tour at tree line in the Central Altai

Abstract

We studied the cones of Siberian stone pine (Pinus sibirica Du Tour) at its treeline in the forest tundra ecotone in the Severo-Chuisky Range, the Altai Mountains, Russia. We have registered length, diameter and form of apophysis, the number of sterile and fertile scales in the cones, the number of ovules and the number of seeds, including developed and underdeveloped seeds, and the developed seeds/ovules ratio. The cones and seeds are produced below 2350 m a. s. l under arid conditions (east-south-eastern slope) and below 2390 m a. s. l. under more humid conditions (west-north-western slope). These altitudes are reproductive line of Siberian stone pine. The predominant forms of the cones near this line are cone-like, spherical and cylindrical. Apophyses are mostly tuberous, hook-like and flat. The most (50%) of the sampled cones have the cylindrical form. The number of ovules varied from 84.6 to 102.4 per cone, the number of seeds were from 76.7 to 98.9 per cone, and the developed seeds were 74.5 to 95.7 per cone. The lowest proportion of developed seeds was registered for cones sampled on arid east-south-eastern slope in 2011. The cones with tuberous apophysis have the highest number of seeds (up to 103.6–110 per cone under more humid and 87.3–104.4 per cone under more arid conditions). Cones gathered at 2235–2390 m a. s. l. have low presence of underdeveloped seeds (1.0 to 3.2 %) and high developed seeds/ovules ratio (87.2 to 93.7 %).

Keywords

• Siberian stone pine
• cones
• seeds
• Severo-Chuisky range
• Altai