马尾松种子萌发与幼苗生长异养转自养生理过程研究

Transition point from heterotrophic to autotrophic in germination and seedling growth of Masson pine

以马尾松成熟种子为研究对象,选取了马尾松种子萌发过程中的5个时期作为观测点,测定了各时期种子生长量的变化,并通过GC-MS技术检测了脂肪酸的差异;用HLPC-MS技术测定种子萌发过程中的蛋白质;利用Li-6400光合测量仪测定了光合作用的起始点。结果显示:在前2个检测时期,马尾松种子的脂肪酸、淀粉含量最高,随着萌发活动的进行转变为小分子物质供给根和芽的生长,在幼苗期含量降至0。由单向电泳可知,在出芽前3个时期的蛋白质条带位置基本不变,仅丰度降低;而在出芽时出现了大分子量的条带,于幼苗期汇聚于52.0 ku的位置。选取成熟期与幼苗期的明显差异蛋白质点进行分析,结果分别表示为贮藏性蛋白——松球蛋白和光合作用关键酶——Rubisco。说明随着贮藏性蛋白质的降解供能,形成了新的功能性蛋白质以调控生长。马尾松因其脂肪含量高,在生长初期主要依靠动员贮藏性脂肪和蛋白质提供能量和原料,尤其是在胚根突破种皮时,物质代谢旺盛。种子萌发过程中进行了由异养到自养的转变,根据G2期出现的Rubisco和CO2补偿点判定此期为转折点。

In this study five periods were chosen as the observation points during germination and the increment change of the seed of Masson pine（ Pinus massoniana） of each period were measured. Meanwhile,The GC-MS,HPLC-MSn and Li-6400 CO2 were used to analyze the contents of fatty acids,the compositions of proteomics and the photosynthesis rate of the seeds respectively during the germination. The results showed that the contents of fatty acid and starch were the highest in the first two periods. During the germination stage,the fat and starch were transformed to small molecular substances to supply the development of root and bud,and the value reduced to 0 at seeding stage. The results of SDS-PAGE showed that the positions of the protein bands were unchanged but only the abundances of the protein were reduced. The high molecular band was emerged during budding,and the molecular weight was reached 52. 0 k Da in seedling stage. Significant difference protein spots in maturity and seedling were analyzed,they were storage protein-cones protein and the key enzyme of photosynthesis-Rubisco,which indicated that the new functional protein was formed to regulate the growth with the storage protein degrading. Because of a high content of fat in Masson pine,the storage fat and protein were mobilized to supply energy and raw material in early growth stage of Masson pine. The material metabolism was very vigorous,especially while the radicle broke through the seed coat. At last,during the germination stage,the Masson pine seed underwent the process from heterotrophic to autotrophic,and this stage was predicated as the turning point according to the appearing of Rubisco and the compensation point of CO2.