以'博辣红帅'辣椒(Capsicum annuum L.)为材料,探究了幼苗期不同光质补光对其生长、光合特性、碳水化合物积累、丛枝菌根真菌(AMF)定殖以及磷吸收的影响.结果表明:与对照白光(WL)相比,补充红光(R)和蓝光(B)均能显著增加辣椒幼苗生物量和壮苗指数;与补充蓝光相比,补充红光对叶片光饱和光合速率、光合色素积累、根系中总糖含量、蔗糖比重以及独脚金内酯(SL)含量的促进效果更为明显.同时,幼苗期补充红光和蓝光均能显著促进后续白光和缺磷条件下AMF的定殖和辣椒干物质积累,并提高根系SL含量、PT4、PT5基因表达以及植株磷含量,以补充红光效果更为明显.以上结果表明,辣椒幼苗期补充红光有利于幼苗生长以及碳水化合物、SL在根部的积累,进而对后续缺磷条件下AMF的定殖以及幼苗对磷的吸收具有明显的促进作用.

[目的]研究补照适量远红光(FR)对辣椒幼苗生长发育和非生物胁迫抗性的调控作用,旨在为实际生产过程中利用精确的光环境调控手段培育壮苗提供理论依据.[方法]以辣椒'博辣红帅'品种为研究材料,将苗龄7 d的辣椒幼苗置于LED光源对照光谱(NL;红R/蓝B=3/1,光量子通量密度PPFD为150 μmol·m-2·s-1)及在此基础上分别补充10 μmol.m-2·s-1远红光(6％FR)、20 μmol·m-2·s-1远红光(13％FR)和30 μmol·m-2·s-1远红光(20％FR)的处理组光谱环境条件下培养,并于苗龄21 d时进行低温和干旱处理.通过测定生物量、抗性相关基因表达、抗氧化酶活性、激素含量、叶绿素荧光参数以及叶片相对电导率等,探究补充6％FR对辣椒幼苗生长和非生物胁迫抗性的影响.[结果]与对照光谱相比,补充6％FR显著提高了辣椒幼苗株高、茎粗、干鲜重以及壮苗指数(P＜0.05).低温胁迫下,相比于对照光谱组,补充6％FR显著提高了辣椒叶片冷响应基因CBF1和抗氧化酶相关基因Cu/Zn-SOD、GR、APX、CAT,DHAR的表达水平,超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、脱氢抗坏血酸还原酶(DHAR)、过氧化氢酶(CAT)、谷胱甘肽还原酶(GR)活性比对照分别增加25.2％、53.6％、55.8％、72.7％和33.4％,抗逆相关激素脱落酸(ABA)的含量提高69.5％.同时,低温胁迫下补充6％FR后辣椒叶片PSII最大光化学效率(Fv/Fm)较对照光谱组显著升高,而相对电导率(REL)显著降低,表明补充6％FR缓解了低温下PSII光抑制和叶片细胞的损伤,提高了辣椒幼苗的耐冷性.此外,干旱胁迫下,相比于对照光谱组,补充6％FR使辣椒幼苗的抗氧化酶SOD、GR、APX、CAT、DHAR活性分别增加13.7％、38.0％.37.2％、27.6％和23.7％,ABA含量和PSII实际光化学效率(ΦPSⅡ)也显著升高,而REL则明显降低,表明补充6％FR减轻了干旱胁迫引起的PSII光抑制和膜脂过氧化,提高了辣椒幼苗的耐旱性.[结论]补充6％FR不仅可促使辣椒壮苗的形成,还可通过增加抗氧化酶活性和ABA含量提高辣椒幼苗对低温胁迫和干旱胁迫的抗性.

Taking pepper ‘Bola Hongshuai’, cucumber ‘Jinyan No. 4’ and lettuce ‘Batavia’ as experimental materials, the combinations of three groups of photosynthetic photon flux density (PPFD) [160, 200 and 240 μmol/(m2•s)] and three groups of photoperiod (12, 15, 18 h/d) were set up to form eight groups of different daily light integral (DLI) treatments to study the effects of DLIs of light emitting diode (LED) on the growth of their seedlings. The results showed that the optimal light conditions were PPFD of 160 μmol/(m2•s) with photoperiod of 15 h/d [DLI of 8.6 mol/(m2•d)] for ‘Bola Hongshuai’ pepper seedlings, PPFD of 200 μmol/(m2•s) with photoperiod of 15 h/d [DLI of 10.8 mol/(m2•d)] for ‘Jinyan No. 4’ cucumber seedlings, and PPFD of 200 μmol/(m2•s) with photoperiod of 18 h/d [DLI of 13.0 mol/(m2•d)] for ‘Batavia’ lettuce seedlings. The results provide optimized LED light environment parameters for vegetable seedling production.

The ability to interpret daily and seasonal fluctuations, latitudinal and vegetation canopy variations in light and temperature signals is essential for plant survival. However, the precise molecular mechanisms transducing the signals from light and temperature perception to maintain plant growth and adaptation remain elusive. We show that far-red light induces PHYTOCHROME-INTERACTING TRANSCRIPTION 4 (SlPIF4) accumulation under low-temperature conditions via phytochrome A in Solanum lycopersicum (tomato). Reverse genetic approaches revealed that knocking out SlPIF4 increases cold susceptibility, while overexpressing SlPIF4 enhances cold tolerance in tomato plants. SlPIF4 not only directly binds to the promoters of the C-REPEAT BINDING FACTOR (SlCBF) genes and activates their expression but also regulates plant hormone biosynthesis and signals, including abscisic acid, jasmonate and gibberellin (GA), in response to low temperature. Moreover, SlPIF4 directly activates the SlDELLA gene (GA-INSENSITIVE 4, SlGAI4) under cold stress, and SlGAI4 positively regulates cold tolerance. Additionally, SlGAI4 represses accumulation of the SlPIF4 protein, thus forming multiple coherent feed-forward loops. Our results reveal that plants integrate light and temperature signals to better adapt to cold stress through shared hormone pathways and transcriptional regulators, which may provide a comprehensive understanding of plant growth and survival in a changing environment.