Webber Joe, Ott Peter, Owens John, Binder Wolfgang
British Columbia Ministry of Forests, Research Branch, P.O. Box 9536, Station Provincial Government, Victoria, BC V8W 9C4, Canada.
Tree Physiol. 2005 Oct;25(10):1219-27. doi: 10.1093/treephys/25.10.1219.
Two temperature regimes were applied during reproductive development of seed and pollen cones of interior spruce (Picea glauca (Moench) Voss and Picea engelmannii (Parry) complex) to determine temperature effects on the adaptive traits of progeny. In Experiment 1, identical crosses were made on potted interior spruce using untreated pollen followed by exposure to a day/night temperature of 22/8 or 14/8 degrees C with a 12-h photoperiod during the stages of reproductive development from post-pollination to early embryo development. Frost hardiness and growth of progeny from seed produced in the two temperature treatments were measured over a 4-year period. Elevated temperature significantly affected both seed-cone development and the adaptive properties of the progeny. Seed cones exposed to the 22/8 degrees C treatment reached the early embryo stage in 53 days versus 92 days in the 14/8 degrees C treatment. Seed yields, cotyledon emergence and percent germination were also significantly enhanced by the 22/8 degrees C treatment. Progeny from seed produced in the higher temperature treatment showed significantly reduced spring and fall frost hardiness, but the elevated temperature treatment had no significant effects on time of bud burst, growth patterns or final heights. In Experiment 2, single ramets of the same clone were subjected to a day/night temperature of 20/8 or 10/8 degrees C during pollen cone development, starting from meiosis and ending at pollen shedding. The two populations of pollen were then crossed with untreated seed cones. Compared with pollen cones exposed to the 10/8 degrees C treatment, pollen cones exposed to the 20/8 degrees C treatment during development reached the shedding stage 2-4 weeks earlier, whereas pollen yields, in vitro viability and fertility (seed set) were significantly lower; however, the resulting progeny displayed no treatment differences in frost hardiness or growth after 1 year. Results suggest that seed orchard after-effects could be caused by temperature differences between orchard site and parent tree origin and that this effect acts on maternal development. Gametophytic (pollen or megagametophyte or both) and early embryo (sporophytic) selection are possible mechanisms that may explain the observed results. Although the effects are biologically significant, they are relatively small and do not justify changes in current deployment strategies for seed orchard seed.
在云杉（白云杉（Moench）Voss和恩氏云杉（Parry）复合体）种子球果和花粉球果的生殖发育过程中，应用了两种温度模式，以确定温度对后代适应性状的影响。在实验1中，对盆栽的内陆云杉进行相同的杂交，使用未处理的花粉，然后在从授粉后到早期胚胎发育的生殖发育阶段，使其暴露于22/8或14/8摄氏度的日/夜温度下，光周期为12小时。在4年的时间里，测量了两种温度处理下产生的种子后代的抗冻性和生长情况。温度升高显著影响了球果发育和后代的适应特性。暴露于22/8摄氏度处理的球果在53天内达到早期胚胎阶段，而在14/8摄氏度处理下则为92天。22/8摄氏度的处理也显著提高了种子产量、子叶出土率和发芽率。高温处理产生的种子后代在春季和秋季的抗冻性显著降低，但高温处理对芽萌发时间、生长模式或最终高度没有显著影响。在实验2中，从减数分裂开始到花粉散落，对同一克隆的单株分株在花粉球果发育期间进行20/8或10/8摄氏度的日/夜温度处理。然后将这两个花粉群体与未处理的种子球果杂交。与暴露于10/8摄氏度处理的花粉球果相比，发育期间暴露于20/8摄氏度处理的花粉球果提前2 - 4周达到散落阶段，而花粉产量、体外活力和育性（结实率）显著较低；然而，所产生的后代在1年后的抗冻性或生长方面没有表现出处理差异。结果表明，种子园的后续效应可能是由种子园地点与母树起源地之间的温度差异引起的，并且这种效应作用于母体发育。配子体（花粉或大配子体或两者）和早期胚胎（孢子体）选择可能是解释观察结果的机制。尽管这些效应在生物学上具有重要意义，但它们相对较小，并不足以证明改变当前种子园种子的部署策略是合理的。
