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。

L-精氨酸在植物中除作为一种重要的氮素贮藏营养物供再利用外，还是生成多胺和一氧化氮（NO）等的前体物质，而多胺和一氧化氮都是植物中重要的信使分子，参与包括生长发育、抗逆性等在内的几乎所有的生理生化过程。精氨酸脱羧酶（ADC）、精氨酸酶和一氧化氮合酶（NOS）是L-精氨酸分解代谢的关键酶，精氨酸可经ADC 或精氨酸酶-鸟氨酸脱羧酶（ODC）途径形成多胺，也可经NOS 途径形成NO，3 个酶活性的相对强弱，决定了精氨酸的代谢方向。根系在越冬期间会积累丰富的精氨酸；精氨酸代谢对于植物感知和适应环境变化有重要意义。

The effect of plant growth substance and fertilizer on root formation was studied in new planted apple tree (Malus pumila Mill / Malus hupenensis Rhed). The results indicated that urea and IBA (Indolebutyric acid) and sheep dung all increased the total number and activity of new roots and changed the ratio of absorbing root to extensive root obviously. Urea increased the number of extensive root and decreased the ratio of root to shoot mostly. IBA lengthened the extensive root and increased the ratio of root to shoot obviously. Sheep dung increased the number of absorbing root and increased the ratio of absorbing root to extensive root, divided new root into mangy branches, increased the fresh weight of root and thicken extensive root. The fresh weight of root increased and the ratio of root to shoot declined after urea added to sheep dung. Both the ratio of absorbing root to extensive root and root fresh weight was increased after IBA added to sheep dung, then the ratio of root to shoot had no change obviously.

促分裂原活化蛋白激酶(mitogen-activated protein kinases, MAPKs) 是一类丝氨酸/ 苏氨酸(Ser/ Thr) 蛋白激酶，人们已在多种植物中发现大量MAPK家族成员。它们同动物和酵母MAPK类似,由MAPKs、MAPKKs (MAPK kinases) 、MAPKKKs (MAPKK kinases)等3 种类型的激酶构成一个MAPK级联途径(MAPK cascade)，在传递激素和环境胁迫等多种信号的过程中起作用。本文着重介绍了MAPK级联途径在植物病原物侵染、机械伤害等逆境信号传递过程中的作用。

Recently, research on Ca2+ transport in plants has been focused on cellular andmolecular level. But the uptake, transport and distribution are also very important for calcium to accomplish its function at whole plant level. There are many cells along the way of transport of Ca2+ from root to shoot, and Ca2+ passes either through the cytoplasm of cells linked by plasmodesmata (the symplast) or through the spaces between cells (the apoplast), which include Ca2+ uptake by root cells, Ca2+ transport from root cortex to and through the xylem, and then out of it into leaves or fruits. Ca2+ channels, Ca2+/H+ antiporter and Ca2+-ATPase play roles in the uptake and transport of Ca2+ in root cells. To be transported fromroot surface to xylem, Ca2+ needs to traverse endodermal cells and xylem parenchyma cells. Endodermal Casparian band, the main barrier for the apoplastic movement of ions into the stele, compels some Ca2+ to enter root symplast through Ca2+ channels in endodermal cells and then reach xylem parenchyma. Ca2+-ATPasemay drive Ca2+ into the stelar apoplast from xylem parenchyma. Some Ca2+ effuses from endodermal cell and then get to xylem through apoplastic pathway. Ca2+ is transported in plant xylem vessel in chelate form and the speed of water flow is the key factor Ca2+ transport via xylem in trunk. There are both apoplastic and symplastic pathways of Ca2+ transport in fruit or leaf tissue too.