Kirschbaum M U, Pearcy R W
Department of Botany, University of California, Davis, California 95616.
Plant Physiol. 1988 Aug;87(4):818-21. doi: 10.1104/pp.87.4.818.
When leaves of Alocasia macrorrhiza that had been preconditioned in 10 micromoles photons per square meter per second for at least 2 hours were suddenly exposed to 500 micromoles photons per square meter per second, there was an almost instantaneous increase in assimilation rate. After this initial increase, there was a secondary increase over the next minute. This secondary increase was more pronounced in high CO(2) (1400 microbars), where assimilation rate was assumed to be limited by the rate of regeneration of ribulose 1,5-bisphosphate (RuBP). It was absent in low CO(2) (75 microbars), where RuBP carboxylase/oxygenase (Rubisco) was assumed to be limiting. It was therefore concluded that it represented an increase in the capacity to regenerate RuBP. This fast-inducing component not only gained full induction rapidly, but also lost it rapidly in low photon flux density (PFD) with a half time of 150 to 200 seconds. It was concluded that in environments with fluctuating PFD, this fast-inducing component is an important factor in determining a leaf's potential for photosynthetic carbon gain. It is especially important during brief periods (<30 seconds) of high PFD that follow moderately long periods (1 to 10 minutes) of low PFD.
将预先在每秒每平方米10微摩尔光子条件下处理至少2小时的海芋叶片突然暴露于每秒每平方米500微摩尔光子时，同化率几乎立即增加。在这一初始增加之后，在接下来的一分钟内出现了二次增加。这种二次增加在高二氧化碳（1400微巴）条件下更为明显，在这种情况下，同化率被认为受1,5-二磷酸核酮糖（RuBP）再生速率的限制。在低二氧化碳（75微巴）条件下则不存在这种二次增加，在这种情况下，核酮糖-1,5-二磷酸羧化酶/加氧酶（Rubisco）被认为是限制因素。因此得出结论，它代表了RuBP再生能力的增加。这种快速诱导成分不仅能迅速获得完全诱导，而且在低光子通量密度（PFD）下也能迅速失去诱导，半衰期为150至200秒。得出的结论是，在PFD波动的环境中，这种快速诱导成分是决定叶片光合碳同化潜力的一个重要因素。在低PFD持续较长时间（1至10分钟）后紧接着的短暂高PFD时期（<30秒），它尤为重要。
