Viikki Plant Science Centre (ViPS), Organismal and Evolutionary Biology (OEB), Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Finland.
IFEVA, Facultad de Agronomía, Universidad de Buenos Aires and CONICET, Av. San Martín 4453,1417 Buenos Aires, Argentina; and Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires-CONICET,1405 Buenos Aires, Argentina.
Funct Plant Biol. 2020 Feb;47(3):226-238. doi: 10.1071/FP19053.
The UV-A/blue photoreceptors phototropins and cryptochromes are both known to contribute to stomatal opening (Δgs) in blue light. However, their relative contributions to the maintenance of gs in blue light through the whole photoperiod remain unknown. To elucidate this question, Arabidopsis phot1 phot2 and cry1 cry2 mutants (MTs) and their respective wild types (WTs) were irradiated with 200 μmolm-2s-1 of blue-, green- or red-light (BL, GL or RL) throughout a 11-h photoperiod. Stomatal conductance (gs) was higher under BL than under RL or GL. Under RL, gs was not affected by either of the photoreceptor mutations, but under GL gs was slightly lower in cry1 cry2 than its WT. Under BL, the presence of phototropins was essential for rapid stomatal opening at the beginning of the photoperiod, and maximal stomatal opening beyond 3 h of irradiation required both phototropins and cryptochromes. Time courses of whole-plant net carbon assimilation rate (Anet) and the effective quantum yield of PSII photochemistry (ΦPSII) were consistent with an Anet-independent contribution of BL on gs both in phot1 phot2 and cry1 cry2 mutants. The changing roles of phototropins and cryptochromes through the day may allow more flexible coordination between gs and Anet.
UV-A/蓝光光受体光敏色素和隐花色素都被认为有助于蓝光下的气孔开放（Δgs）。然而，它们在整个光周期内通过蓝光维持 gs 的相对贡献仍然未知。为了阐明这个问题，用 200 μmolm-2s-1 的蓝光、绿光或红光（BL、GL 或 RL）对拟南芥 phot1 phot2 和 cry1 cry2 突变体（MTs）及其各自的野生型（WTs）进行辐照，整个光周期为 11 小时。在 BL 下，气孔导度（gs）高于 RL 或 GL。在 RL 下，光受体突变对 gs 没有影响，但在 GL 下，cry1 cry2 的 gs 略低于其 WT。在 BL 下，光敏色素对光周期开始时快速的气孔开放是必不可少的，而超过 3 小时的辐照需要光敏色素和隐花色素才能达到最大的气孔开度。整株植物净碳同化率（Anet）和 PSII 光化学有效量子产量（ΦPSII）的时间过程与 BL 在 phot1 phot2 和 cry1 cry2 突变体中的 gs 上的 Anet 独立贡献一致。光敏色素和隐花色素在一天中的作用变化可能允许 gs 和 Anet 之间更灵活的协调。
