红将军苹果离体叶片高频再生体系研究

以中熟红富士品种红将军组培苗的叶片为试材,研究了离体叶片诱导再生不定芽过程中不同激素种类与组合、暗处理时间、取叶部位等因素对再生率的影响。结果表明,试管苗继代培养3～4代,当代培养25～30d,取顶部嫩叶3～4枚,剪除叶片边缘,将剪切的叶片中部以近轴面接触在最佳诱导分化培养基上:MS+TDZ1.0mg/L+IAA0.5mg/L+蔗糖30g/L,培养基pH值5.8,黑暗培养10d后,转入光照培养条件下,再生频率达100%,再生芽数平均4.6个。叶片再生不定芽分化后15～20d转接到苹果继代培养基MS+BA0.5mg/L+IBA0.1mg/L上,当不定芽长度约2cm时再转接到1/2MS+IBA0.5mg/L+NAA0.5mg/L+Ac0.5g/L+蔗糖2%的生根培养基上,光培养15d后,生根率可达86.0%。     

激发子物质处理富士苹果果实后抗轮纹病病菌侵染的研究

富士苹果果实经硝普钠(SNP)、茉莉酸甲酯(MeJA)、水杨酸(SA)和氯化钙处理后再接种轮纹病菌,各个处理均能不同程度地防止轮纹病菌的侵染和扩展,其中MeJA和SNP处理效果最明显,烂果率和烂果面积分别比对照减少26.7%、26.7%和41.6%、36.2%。另外,还对各处理果实的PAL、SOD、POD和PPO活性变化进行了分析,结果表明,接种轮纹病菌的72h内,4个处理的PAL和PPO活性均表现出先升后降的趋势,而SOD和POD活性变化除SA处理一直保持平稳波动上升外,其余3个处理也表现为先升后降趋势;各处理的PAL和POD峰值出现的时间均早于SOD和PPO。PAL、POD和PPO活性峰值和平均值均以MeJA处理最高,SOD活性峰值和平均值SNP处理最高。     

Reduction of apple tree height (Malus domestica Borkh) cv. Ultra Red Gala/MM111 does not decrease fruit yield and quality

In Chile, like in other countries, a high percentage of apple (Malus domestica Borkh) orchards are grafted on vigorous or semi-vigorous rootstocks. The need to decrease the amount of labor involved and increase efficiency has motivated this study on the effect of reducing the height of cv. Ultra Red Gala/MM111 trees in a commercial orchard in the Maule Region of Chile. Apple trees were planted in 2003, and their tree heights were adjusted to 2.5, 3.0 and 3.6 m prior to blooming in 2006. The reduction of plant height from 3.6 m to 2.5 m determined a significant reduction in canopy volume (26% and 29% in 2007/2008 and 2008/2009, respectively), but no differences were detected in leaf area index (LAI) and the photosynthetic active radiation (PAR) transmitted through the canopy. However, a higher proportion of the canopies of the shorter trees had over 30% of incident PAR, the threshold for the production of good fruit quality and flower-bud differentiation. There were no differences in fruit production among plant heights, accumulating 131 tonnes ha⁻¹ in the three growing seasons. Over the three seasons, the shortest plants (2.5 m) required 19, 57 and 42% less labor time at harvest, respectively, than the plants maintained at a height of 3.6 m. There were no evident differences in fruit quality among the treatments; flesh firmness varied between 73.0 and 74.0 N, soluble solids between 11.6 and 12.6°Brix, mean weight between 180 and 200 g, and the percentage of red coloring exceeded 59% of the Premium fruit in the three growing seasons. Our results suggest that it is possible to manage plants with reduced height on semi-vigorous rootstocks and thus reduce the time necessary for harvesting, without affecting fruit yield and quality.