Gradual defoliation (lower leaves yellow and fall) ... Overwatering (root damage), underwatering (not enough water to support full foliage), lack of sufficient light, or lack of fertilizer.

• 逐渐落叶（下端叶子变黄脱落）...浇水过多（伤根），浇水不足（没有足够的水供所有的叶子），缺光，缺肥。