本文采用单克隆抗体酶联免疫吸附分析法测定了UV-B诱导DNA产生的CPD和6-4PP。经0.5mW/cm2UV-B处理15min的小牛胸腺和鲱鱼精DNA，CPD和6-4PP含量显著增加，而未经UV-B处理的对照DNA则没有二聚体形成。

含钙培养液（对照）和位用IAA处理的原生质体的体积和45Ca2+放射性强度均无变化。IAA处理含钙培养液中的原生质体。5min后45Ca2+积累明显增多，体积开始膨大。处理30min时45Ca2+积累最多，此时原生质体的膨大效应最好，随后45Ca2+积累和膨大效应逐渐下降。K+、2n2+、Ba2+、Mg2+等也可在一定程度上代替Ca2+使原生质体体积膨大。原生质体的吸水在膨大中起着一定作用。EGTA、LaCl3和verapamil均抑制IAA诱导的原生质体45Ca2+积累和体积膨大。说明Ca2+可能在6BA诱导原生质体嘭大的过程中起着重要作用。

Protoplasts isolated from red-light-grown maize (Zea mays L.) coleoptiles shrank transiently upon brief exposure (e.g. 30 s) to blue light under background irradiation with red light. The maximal volume reduction (about 4% at a saturating fluence) occurred about 5 min after blue-light stimulation. The response was prevented by the anion-channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoic acid. Red light and far-red light did not induce any comparable response. Protoplasts of different sizes and those isolated from different coleoptile positions showed similar responses. After treatment with a saturating blue-light pulse, the protoplasts became responsive to a second pulse and gained full responsiveness within 5 min, suggesting that the photoreceptor system involves a dark-reversible component. The response to continuous blue light was also found to be transient. The protoplast volume was reduced during about 6 to 9 min of irradiation and returned within the next 30 min to the control level. The response to continuous blue light was saturated at 30 pmol m-2s-1. However, when the fluence rate was enhanced 10-fold after a period of irradiation at 30 pmol m-2s-1, the protoplasts showed another shrinking response. These and other kinetic results indicate that the photoreceptor system undergoes a photosensory adaptation. Crowth in different zones of the coleoptile was inhibited by blue light transiently after pulse stimulation, as well as during continuous stimulation. It was concluded that the observed protoplast shrinking is related to the blue-light-induced inhibition of coleoptile growth.

This paper studied on the role of calcium in 6-BA-induced swelling of protoplasts isolated from hypocotyl in etiolated mung bean(Phaseolus radiatus L.) seedlig. Protoplasts incubated in CaCl2-bearing medium without hormone maintained a constant volume. To treat with 6-BA, they began to swell after 15 minutes, and continually swelled to the maximum volume 30 minutes later when they were treated with 10-1 mol/L 6-BA(Fig.2). However, the protoplasts could not swell when 6-BA was added into the medium without CaCl2(Fig.1). It was suggested that Ca2+ was necessary for 6-BA to induce protoplast swelling. 6-BA enabled the protoplasts to swell in less extent when K-. Zn2+, Ba2+or Mg2-instedad of Ca2-(Fig.3). Radioisotope experiments showed that K+influx incrased when Ca2+ as replaced by K+(Fig.4). Ca2+ accumulation in protoplasis treated by 6-BA was munch higher than that of control, and the time course of Ca2+ accumu-lation was similar to protoplasts swelling (Fig5). 45Ca2+level and the swelling of protoplasis were sharply declined when EGTA, verapamil or LaCcl3 was added into the medium(Table 1,2and3). These results indiated that Ca2+ may play an important role in 6-BA-induced swelling.

Protoplasts isolated from red-light-adapted Arabidopsis hypocotyls and incubated under red light exhibited rapid and transient shrinking within a period of 20 min in response to a blue-light pulse and following the onset of continuous blue light. Long-persisting shrinkage was also observed during continuous stimulation. Protoplasts from a hy4 mutant and the phytochrome-deficient phyA/phyB double mutant of Arabidopsis showed little response, whereas those from phyA and phyB mutants showed a partial response. It is concluded that the shrinking response itself is mediated by the HY4 gene product, cryptochrome 1, whereas the blue-light responsiveness is strictly controlled by phytochromes A and B, with a greater contribution by phytochrome B. It is shown further that the far-redabsorbing form of phytochrome (Pfr) was not required during or after, but was required before blue-light perception. Furthermore, a component that directly determines the blue-light responsiveness was generated by Pfr after a lag of 15 min over a 15-min period and decayed with similar kinetics after removal of Pfr by far-red light. The anion-channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoic acid prevented the shrinking response. This result, together with those in the literature and the kinetic features of shrinking, suggests that anion channels are activated first, and outward-rectifying cation channels are subsequently activated, resulting in continued net effluxes of Cl2 and K1. The postshrinking volume recovery is achieved by K1 and Cl2 influxes, with contribution by the proton motive force. External Ca21 has no role in shrinking and the recovery. The gradual swelling of protoplasts that prevails under background red light is shown to be a phytochrome-mediated response in which phytochrome A contributes more than phytochrome B.