紧凑型梨解剖结构及内源激素变化

Study on the changes of anatomical structure and endogenous hormones in the pear trees of compact type

以两类不同株型梨品种(系)为试材,研究了紧凑型与普通型梨一年生嫁接苗的形态特征、生长发育特点、内源激素含量变化及15 a生树新梢的解剖结构。结果表明,与普通型相比,紧凑型嫩梢中脱落酸(ABA)和赤霉素(GA3)含量显著较少,细胞分裂素(ZR及Z+ZR)含量显著较多,生长素(IAA)含量稍高于普通型但差异不显著。紧凑型新梢顶端木薄壁细胞显著增加,导管、木质纤维和可溶性糖显著减少。首次提出确定梨紧凑型基本指标为新梢顶端木质部中木质纤维密度低于1 300个.mm-2,木薄壁细胞密度高于1 700个.mm-2,导管密度低于270个.mm-2;紧凑型梨树节间变短可能是赤霉素(GA3)含量减少引起的,顶端的膨大生长等现象则可能是细胞分裂素积累引起的。

Two types of pear trees were studied on morphological characteristics,growth and development characteristics,changes in endogenous hormones in one-year old grafted plantlets and anatomical structure in new shoots of 15-year-old pear tree.The results showed that the shoot tips of compact type contained significantly lower level of ABA,GA3 and higher level of cytokinins（ZR and Z＋ZR）than those of common type,only was the level of IAA slightly higher but no significant dif-ference compared with common type existed.In the apex of the new shoots of compact type,there were significantly more wood parenchymatous cells,less vessels and lower level of lignocelluloses and soluble sugar.Two conclusions are firstly put forward： the first is that when the density of lignocelluloses is lower than 1300 ind.mm-2,the density of wood parenchymatous cell is higher than 1700 ind.mm-2,the density of vessels is lower than 270 ind.mm-2 in the xylem of the shoot apex,it can be preliminary identified as compact type.The second is that the short internodes of compact type may be caused by the reduc-tion of gibberellins,and the swelling of shoot apex may be induced by the accumulation of cytokinins.