Legros S, Mialet-Serra I, Caliman J-P, Siregar F A, Clement-Vidal A, Fabre D, Dingkuhn M
CIRAD, UPR Système de Pérennes, Montpellier cedex 5, France.
Ann Bot. 2009 Nov;104(6):1183-94. doi: 10.1093/aob/mcp216. Epub 2009 Sep 11.
Despite its simple architecture and small phenotypic plasticity, oil palm has complex phenology and source-sink interactions. Phytomers appear in regular succession but their development takes years, involving long lag periods between environmental influences and their effects on sinks. Plant adjustments to resulting source-sink imbalances are poorly understood. This study investigated oil palm adjustments to imbalances caused by severe fruit pruning.
An experiment with two treatments (control and complete fruit pruning) during 22 months in 2006-2008) and six replications per treatment was conducted in Indonesia. Phenology, growth of above-ground vegetative and reproductive organs, leaf morphology, inflorescence sex differentiation, dynamics of non-structural carbohydrate reserves and light-saturated net photosynthesis (A(max)) were monitored.
Artificial sink limitation by complete fruit pruning accelerated development rate, resulting in higher phytomer, leaf and inflorescence numbers. Leaf size and morphology remained unchanged. Complete fruit pruning also suppressed the abortion of male inflorescences, estimated to be triggered at about 16 months before bunch maturity. The number of female inflorescences increased after an estimated lag of 24-26 months, corresponding to time from sex differentiation to bunch maturity. The most important adjustment process was increased assimilate storage in the stem, attaining nearly 50 % of dry weight in the stem top, mainly as starch, whereas glucose, which in controls was the most abundant non-structural carbohydrate stored in oil palm, decreased.
The development rate of oil palm is in part controlled by source-sink relationships. Although increased rate of development and proportion of female inflorescences constituted observed adjustments to sink limitation, the low plasticity of plant architecture (constant leaf size, absence of branching) limited compensatory growth. Non-structural carbohydrate storage was thus the main adjustment process.
尽管油棕的结构简单且表型可塑性较小，但其物候复杂且存在源库相互作用。叶元按规律依次出现，但其发育需数年时间，环境影响与对库的效应之间存在较长的滞后期。植物对由此产生的源库失衡的调节机制尚不清楚。本研究调查了油棕对重度果实修剪导致的失衡的调节情况。
2006 - 2008年在印度尼西亚进行了一项为期22个月的实验，设两个处理（对照和完全果实修剪），每个处理6次重复。监测了物候、地上营养器官和生殖器官的生长、叶片形态、花序性别分化、非结构性碳水化合物储备动态以及光饱和净光合速率（A(max)）。
完全果实修剪造成的人为库限制加速了发育速率，导致叶元、叶片和花序数量增加。叶片大小和形态保持不变。完全果实修剪还抑制了雄花序的败育，据估计雄花序败育在果穗成熟前约16个月触发。雌花序数量在估计24 - 26个月的滞后期后增加，这与从性别分化到果穗成熟的时间相对应。最重要的调节过程是茎中同化物储存增加，茎尖干重中近50%为同化物储存，主要为淀粉，而在对照中作为油棕储存的最丰富非结构性碳水化合物的葡萄糖含量下降。
油棕的发育速率部分受源库关系控制。尽管发育速率增加和雌花序比例增加构成了对库限制的明显调节，但植株结构的低可塑性（叶片大小恒定、无分枝）限制了补偿性生长。因此，非结构性碳水化合物储存是主要的调节过程。
