Pullman Gerald S, Johnson Shannon
School of Biology, Georgia Institute of Technology, Atlanta, GA 30332-0620, USA.
Tree Physiol. 2009 Jun;29(6):829-36. doi: 10.1093/treephys/tpp020. Epub 2009 Apr 8.
Stage-specific measurements of female gametophyte (FG) and embryo pH (hydrogen ion concentration) were made through the sequence of loblolly pine (Pinus taeda L.) seed development. The FG tissue from two open-pollinated trees showed similar pH profiles starting at 5.5 shortly after fertilization, increasing to about 6.1 at stage 7, levelling off at 6.3-6.5 towards the end of development and dropping to 6.0 just before cone opening. Measurements of the chalazal end were 0.05-0.2 pH units less than the micropylar end through early-to-mid-development. In contrast, embryo pH maintained a nearly constant value near 7.0 through development. Profiles of pH through seed development were similar whether portrayed by date or stage of embryo present in the seed. The pH profiles assisted in the development of improved embryogenic tissue initiation techniques. When post-autoclaving maturation medium pH was raised from about 5.3 in control medium to 5.7 or 5.5-5.7 with 2(n-morpholino)ethanesulphonic acid, cotyledonary embryo yields increased.
通过火炬松（Pinus taeda L.）种子发育过程，对雌配子体（FG）和胚的pH值（氢离子浓度）进行了特定阶段的测量。来自两棵开放授粉树的FG组织显示出相似的pH值变化曲线，受精后不久pH值从5.5开始，在第7阶段增加到约6.1，发育末期稳定在6.3 - 6.5，球果开裂前降至6.0。在发育早期到中期，合点端的测量值比珠孔端低0.05 - 0.2个pH单位。相比之下，胚的pH值在整个发育过程中保持在接近7.0的恒定值。无论以种子中胚的日期还是阶段来描述，种子发育过程中的pH值变化曲线都是相似的。pH值变化曲线有助于改进胚性组织起始技术的发展。当用2 -（N - 吗啉代）乙磺酸将高压灭菌后的成熟培养基pH值从对照培养基中的约5.3提高到5.7或5.5 - 5.7时，子叶胚产量增加。
