The early-response of roots to water loss and the signal transduction of water loss to abscisic acid (ABA) biosynthesis were studied by polyethylene glycol (PEG 6000) treatments to apple rootstock (Malus hupenensis Reld) seedlings. The results show that the ABA content, the H2O2 production rate, the lipoxygenase (LOX) activity and the protein kinase (PK) activity all increase during water loss (30% PEG treatment) in apple roots. H2O2 content reaches a peak at 30～40 min, then drops and rises again at 180 min following treatment. Increase of H2O2 is the earliest and of ABA content is the latest among these events. The absorbance of H2O2 and inhibition of LOX reduce the ABA accumulation during water loss. Both exogenous H2O2 and soybean LOX are able to increase ABA content. The Ca2+ chelater (EGTA) and the inhibitor of PK and LOX all reduce the increment of ABA after water loss. The activity of LOX and PK increases after treatment by 1 mmol/L H2O2 in intact roots and a PK inhibitor reduces the increase of LOX activity by PEG and H2O2. The PEG treatment-induced increases of H2O2 content, PK and LOX activity all decrease after EGTA pretreatment. It suggests that the Ca2+, protein phosphorylation, active oxygen species and LOX are all involved in the ABA biosynthesis induced by water loss; the change of cytosol Ca2+ and H2O2 is the earliest event and LOX may be a key enzyme in some conditions. The pathway of the signaling cascade associated with water loss and ABA may be: PEG treatment → loss of cell water → loss of cell turgor → mechanical process → Ca2+ → H2O2 → PK → LOX → ABA accumulation.

以5年生盆栽苹果(Malus domestica Borkh/ Malus hupenensis Rhed) 为试材，研究了断根和剪枝等处理对叶片净光合速率(Pn) 、蒸腾速率(Tr) 、气孔导度(Gs) 、水分利用效率(WUE) 的影响及引起WUE变化的原因。结果表明，断根明显提高了WUE，处理后第2～42 天逐渐升高。同时, 断根后Tr、Gs 明显下降，而Pn 和羧化效率(CE) 迅速恢复, 并在第7 天以后明显高于对照; 新根总数及叶片玉米素核苷(ZR)浓度则于第28 天后恢复至对照水平。剪枝使Pn、CE、Tr、Gs 及叶片ZR 浓度升高，但 WUE 只在 28d 后稍高于对照。断根结合剪枝后第2 天，Pn、CE、Tr 及Gs 下降；21d 后Pn 和CE 高于对照，而 Tr 及 Gs 与对照相近，WUE 在后期稍有升高。分析认为，断根通过降低气孔导度极显著地提高了叶片WUE，剪枝则通过提高CE 而使WUE 升高。

本文综述了多胺与果树萌发、座果、果实发育、根系形成、花芽分化、果榭衰老的关系，以及多胺胁迫、多胺与激紊的关系和多胺的吸收运转特性。

The effects of abscisic acid (ABA) on pollen germination and tube growth were studied in pomegranate (Punica granatum L.). Results showed that ABA inhibited pollen germination and tube growth at higher concentrations, over 50 mM, while low ABA concentrations, 0.05～5 mM, showed lower inhibition. The percentage of pollen germination did not change, but both tube growth and the effects of ABA on tube growth were inhibited by 10 mg·L-1 cycloheximide treatment. The inhibitors of ABA biosynthesis, NDGA (nordihydroguaiaretic acid) and fluridone, inhibited pollen germination and tube growth evidently. The degree of inhibition increased gradually along with the increases in ABA concentrations from 20 to 100 mM, and the inhibitory response to tube growth was more significant. ABA (1 mM) could abate the inhibition degree of NDGA and fluridone to tube growth, but could not influence the germination. The result indicated that low ABA concentration was necessary for normal pollen growth.

外源多胺(精胺、亚精胺、腐胺)可增加苹果幼苗新根数量，但效果不及IBA；IBA能够促进多胺与核酸的积累，有效期20-27天;多胺亦可增加RNA，DNA的含量；处理和对照内源多胺与核酸含量均同步变化。