不同光质对桑树幼苗生长和光合特性的影响

光质可影响植物光合特性、形态以及生理过程。本试验研究了不同光质(白光W、红光R、红蓝混合光RB、蓝光B)对桑树植株生长、形态和光合作用的影响。结果表明:与白光对照相比,红光、蓝光和红蓝混合光处理下植株的生长、干物质积累受到抑制;红光处理下植株的株高、叶面积显著高于白光、红蓝混合光、蓝光处理;而白光、红蓝混合光、蓝光处理下植株的LMA、叶绿素a/b比值、可溶性蛋白含量、蔗糖、淀粉含量和叶片总N含量显著高于红光处理;红蓝混合光处理下植株的Pn、Gs、ΦPSⅡ与白光处理相近,红光、蓝光处理下植株的Pn、ΦPSⅡ低于白光、红蓝混合光处理,同时红光、红蓝混合光、蓝光处理下植株的抗氧化酶活性高于白光处理,而MDA含量低于白光处理;红光处理下植株的叶片厚度、栅栏组织和海绵组织厚度显著小于白光处理。因此,一定比例的红蓝混合光可以使桑树植株的生长、光合特性、生理特征和叶片解剖结构与白光下生长植株相近,并减少单质红光、单质蓝光对植株生长发育的不利影响。     

LED光质对非洲菊组培苗增殖及生理特性的影响

为提高非洲菊增殖培养的效率并降低生产能耗,通过发光二极管(LED)设置不同比例的红蓝光组合,研究光质对非洲菊离体培养增殖阶段的影响,通过对丛生苗形态指标和生理生化指标的测定,筛选出最适LED光质条件,并初步探讨其生理机制。结果显示:(1)不同LED光质条件下,非洲菊组培苗的增殖系数差异显著,其中RB4(红蓝光比例为4∶1)处理显著高于其他处理。(2)丛生苗的株高在复合光处理下显著低于R(单一红光)和B(单一蓝光)处理;鲜重和干重在红蓝复合光RB2、RB4、RB8(红蓝光比例分别为2∶1、4∶1和8∶1)处理下均显著高于R、B和对照处理。(3)RB4处理下丛生苗的可溶性糖含量显著高于其他处理,比对照提高了89.62%。(4)LED复合光处理下丛生苗的丙二醛含量显著低于对照,并呈现随红光比例增加而不断降低的趋势;RB2、RB4和RB8处理的超氧化物歧化酶活性显著低于其他处理;除R处理外,其他LED光质处理的丛生苗过氧化氢酶活性均显著高于对照,并以RB4处理丛生苗过氧化氢酶活性最强。研究表明,RB2、RB4和RB8处理有助于提高非洲菊组培苗的增殖系数和干鲜重,并能够促进可溶性糖含量的增加,增强植株自身对活性氧的解毒能力,减轻植株的膜脂过氧化作用,且以RB4处理表现最优,其非洲菊丛生苗的增殖系数和可溶性糖含量显著高于其他处理,干鲜重和过氧化氢酶活性均为最高,丙二醛含量显著低于除单一红光外的其他处理。     

光质对紫背天葵生长、次生代谢和抗氧化胁迫的影响

以紫背天葵为供试材料,采用LED灯精量调控光质和光强,研究相同光照强度(350±5 μmol·m^-2·s^-1)下,白光(W)、红光(R)、蓝光(B)、黄光(Y)、红蓝混合光(RB)、红蓝黄混合光(RBY)对紫背天葵生长、次生代谢和氧化胁迫抗性的影响.结果表明:与白光(W)相比,红光(R)能够显著促进紫背天葵植株的生长以及干物质和可溶性糖含量的积累;而蓝光(B)则抑制紫背天葵的生长;叶绿素含量在有色光处理下均显著降低;虽然红蓝黄混合光(RBY)未能显著提升紫背天葵的干物质含量,但总酚、类黄酮和花青素含量显著提升,这些还原态物质的积累有利于提高紫背天葵的抗氧化能力,在增强自身抗逆性的同时提升营养价值.本研究为光质调控紫背天葵的多样化生产提供了理论依据.     

不同比例红蓝光对番茄幼苗生长和光合作用的影响

为了探索番茄幼苗生长发育对红蓝组合光的响应机制,本试验采用发光二极管(LED)精量调制光源,以番茄品种‘SV0313TG’为试材,设红光(R)、蓝光(B)和红蓝组合光(9R1B、6R1B、3R1B、1R1B、1R3B)7个处理,以白光为对照,研究不同比例红蓝光质对番茄幼苗生长、光合色素含量、光合特性、叶绿素荧光参数及根系活力的影响.结果表明:不同比例红蓝光质处理对番茄幼苗生长的影响具有明显差异.红光显著促进幼苗株高增加,比叶面积增大,胞间CO₂浓度提高,但PSⅡ最大光化学效率(F_v/F_m)、PSⅡ实际光化学效率(Ф_PSⅡ)降低,根系生长受阻,根系活力下降,壮苗指数降低;蓝光下幼苗生长受到明显抑制,叶绿素含量降低,但叶绿素a/b 值升高;红蓝组合光有利于番茄幼苗的生长发育,3R1B处理下植株干物质量、叶绿素含量和光合性能均显著提高,幼苗生长健壮,壮苗指数最大.综上,红蓝组合光能够增加番茄幼苗叶片光合色素含量,提高光合效率,促进植株生长,尤以3R1B处理最佳.     

不同光质对烟草组培苗生长及生理特性的影响

以‘云烟87号’生根组培苗为试材,以荧光灯为对照(CK),采用LED光源发射的单色光谱红光(R)、蓝光(B)、绿光(G)等不同光质配比组合光照处理,研究光质对烟草组培苗生长和生理特性的影响。结果显示:(1)与CK相比,红蓝绿(RBG)和红蓝白(RBW)组合光质使烟草组培苗植株株高、叶长、叶宽、叶面积、茎粗、根数、根长和干重显著增加,植株叶绿素含量也有提高但差异不显著。(2)RBW组合光质照射的植株可溶性糖含量和C/N比值显著高于其他光质处理,RBG组合光质处理植株的游离氨基酸含量显著高于其他光质处理,且各光质及其组合处理的烟草叶片可溶性蛋白含量显著高于对照,红蓝配光(1RB)使植株可溶性淀粉含量较对照显著提高。(3)各光质及其组合处理的烟草膜脂过氧化物MDA含量较对照均显著降低,而其SOD、POD和CAT活性较对照均显著提高;其中红光处理的植株膜脂过氧化物MDA含量最低,CAT活性最高。研究表明,LED光源不同光质及其组合光照均能够显著降低烟草组培苗的MDA含量,降低膜脂过氧化的伤害,促进烟草组培苗的生长,其主要通过调节抗氧化物酶活性的合成代谢来应对光氧化胁迫;LED光源的RBG和RBW组合光质可作为烟草组培苗生根阶段的最适光质。     

不同光质LED弱光对樱桃番茄植株形态和光合性能的影响

基于新型LED光源研究了不同光质弱光对樱桃番茄植株形态和光合性能的影响.结果显示:(1)红蓝光(RB)的基础上添加不同的光色处理,对植株的形态没有显著影响,但对植株生物量有显著影响,能调节生物量的分配.除红蓝黄绿紫复合光处理(Z)外,其他复合光处理的单株总生物量都大于RB处理,添加绿光、黄光、紫光和黄紫光有利于植株地上部的生长,而添加绿光和紫光却抑制植株地下部的生长.(2)除红蓝黄紫复合光(RBYP)和红蓝紫复合光(RBP)处理外,所有处理的光合色素含量都比RB处理高,并以Z处理光合色素含量最高.(3)叶片的光补偿点和表观量子效率以及净光合速率受光质的调控.RBYP处理的最大净光合速率和表观量子效率显著大于其他处理,光补偿点在红蓝绿复合光(RBG)和红蓝黄复合光(RBY)下较大,而在白光(CK)和Z处理下较小.(4)各处理光系统Ⅱ的光能分配存在差异,RB处理光化学淬灭系数较其他处理小,而Z和RBP的非光化学淬灭系数较小,各处理间最大光化学效率及电子传递速率无显著差异.研究发现,复合光质的光色间对植株生长发育的影响是相互协同、相互制约的关系;红蓝黄紫复合光处理植株光合潜能较大,能够在一定程度上缓解红蓝弱光胁迫,促进植株幼苗生长;在红蓝光基础上添加其他光色有利于植株光合色素的积累并促进光合,同时可提高植株光化学效率.     

不同品种菠菜叶肉及叶柄中硝态氮累积与硝酸还原酶活性的关系

盆栽试验条件下,菠菜体内的硝态氮含量及硝酸还原酶（NR）活性因品种和部位而异。硝态氮含量以短缩茎中最高,叶和叶柄中次之,根中最低,且根,冠比越大的品种,其整体植株中的硝态氮含量越低;根尤其是侧根NR活性较高;叶肉和叶柄中硝态氮含量均与根中以内、外源硝酸盐为底物的NR活性呈一定的负相关。     

菠菜叶片中硝态氮还原与叶柄中硝态氮累积的关系

测定了不同生长期在不同施氮水平下3个菠菜品种各器官的硝态氮含量、叶片的硝酸还原酶活性、叶片细胞硝态氮的贮存库和代谢库大小.结果表明:叶柄中硝态氮含量远高于其它器官,其含量与叶片内源/外源硝酸还原酶活性的比值呈负相关;叶片细胞中硝态氮代谢库的大小与叶柄中硝态氮含量之间没有确定的关系.     

不同LED光质对金线莲生长的影响

以福建产金线莲（Anoectochilus roxburghii）为材料,研究不同LED光质（红光、黄光、蓝光）对金线莲生长指标以及叶绿素、气孔的影响。结果表明,红光与黄光有利于金线莲株高增长,与对照相比分别提高18.74%、21.47%,但二者处理的植株较为瘦弱,且红光和黄光处理下的植株叶绿素a和叶绿素b含量较低。蓝光处理下金线莲生长情况较好,叶面积与对照相比增长明显,且叶绿素含量相对较高。不同LED光质处理下的植株气孔频度、长度、宽度与对照相比都有一定增长。     

大豆植株发育过程中不同部位的硝态氮含量和硝酸还原酶活力的变化

同一时期的大豆品种长农5号植株中硝态氮含量是,主茎大于叶柄大于叶片,前二者中硝态氮含量随着生育进程逐渐减少,生育前期由基部向上逐渐增加,鼓粒期以后各节位间无明显变化。营养生长期间,叶片中硝态氮含量较高,不同生殖生长期间或同一时期的不同节位变化不明显。硝酸还原酶活力是成熟叶片中低,幼嫩叶片中高,且随着生育进程逐渐降低。     

Growth of Tsuru-rindo (Tripterospermum japonicum) culturedin vitro under various sources of light-emitting diode (LED) irradiation

We studied the effects of light generated by LEDs on the growth of Tsururindo (Tripterospermum japonicum) shoots. Apical shoots (2–3 cm long) were cultured on MS basal media supplemented with 3% sucrose, and were maintained for four weeks under five different light qualities: F (fluorescent lamp), red LED (R), 70% red + 30% blue LED (R7B3), 50% red + 50% blue (R5B5), or blue LED (B). Rooting was promoted by red light (100%) but was inhibited by blue light. Plant growth, as defined by root number, fresh weight, and chlorophyll content, was generally healthier for cultures irradiated with mixed LEDs, and was the best under R7B3. Ventilation resulted in more rapid apical shoot growth and rooting compared with control plants, when both were treated with the R7B3 system. We demonstrated here that plant growth can be controlled by using LEDs to adjust for the most effective irradiation conditions, compared with the performance observed when conventional fluorescent lamps are utilized.     

Effects of different LED sources on the growth and nitrogen metabolism of lettuce

Using a light-emitting diode (LED) as the light source, the effects of eight different light treatments [white light (control, W), purple light (P), blue light (B), red light (R), green light (G), yellow light (Y), red–blue light in a 9:1 ratio (9R/1B), and red–blue light in a 4:1 ratio (4R/1B)] on the growth, quality and nitrogen metabolism of lettuce were studied. The results showed that compared with the white light, the purple light, blue light, red light, and the red-blue light combination could all increase the biomass of the aboveground part of lettuce to various degrees, while green light and yellow light inhibited lettuce growth. Under blue light, the contents of soluble protein and flavonoid in lettuce were the highest; under red light, the soluble sugar content was the highest, while the contents of soluble protein, free amino acids, and vitamin C (VC) were relatively higher under the 4R/1B light condition. Compared with white light, the sources of purple, blue, and red lights as well as the red–blue light combination all significantly reduced nitrate accumulation in lettuce, and the activities of the nitrogen (N) metabolism-related enzymes such as nitrate reductase, nitrite reductase, glutamine synthetase, glutamate synthase, and glutamate dehydrogenase were increased to varying degrees. In contrast, the contents of nitrate and ammonium N were significantly accumulated in lettuce under green light, and the activities of relative enzymes were significantly reduced. Therefore, the purple light, blue light, and red–blue combination light sources could promote N assimilation and improve the aboveground biomass accumulation in lettuce by improving the activity of the N metabolism-related enzymes in lettuce. Particularly under the 4R/1B light source, the biomass, soluble protein, VC, and total amino acid content were rather high in lettuce, which indicated that the 4R/1B light source could better effectively improve the nutritional quality and promote the growth of lettuce, while yellow light and green light are not suitable to serve as direct sources in a plant factory. These results provide a certain theoretical basis for the regulation of the light environment in cultivation facilities.     

Modified light spectral conditions prior to cryopreservation alter growth characteristics and cryopreservation success of potato (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.) shoot tips in vitro

Light is one of the most important factors affecting growth and morphogenesis of plants. Light intensity, photoperiod and spectral composition greatly affect morphogenetic responses of in vitro plants. Modification of light spectra during recovery after cryopreservation improves survival and regeneration, but the effect of modified light conditions prior to cryopreservation are not known. Therefore, the aim of the present study was to follow the photomorphogenetic response of potato plants (Solanum tuberosum L.) under different light qualities i.e. cool white fluorescent (CW) used as control, warm white (HQI), white LEDs (W), blue LEDs (B), red LEDs (R) and a combination of red with 10?% of blue LEDs (RB) prior to cryopreservation, affecting recovery of cultivars Agrie Dzeltenie, Bintje, Maret, Anti and Désirée in vitro. Light spectral quality had a significant effect on growth characteristics of potato plants in vitro. Red light (R) promoted elongation growth but biomass accumulation remained low under monochromatic light treatments. Some of the pre-cryopreservation light treatments significantly affected post-cryopreservation success. Under blue LEDs, high early recovery was observed for all cultivars tested, whereas under red (R) or (HQI), lowest survival percentages were obtained 2–4 weeks after thawing. Specifically, during early recovery, blue light increased survival from 26 to 66?%, 4 to 31?% and 16 to 48?% for cultivars Agrie Dzeltenie, Anti, and Désirée, compared to illumination by red LEDs. Therefore, light spectral quality prior to cryopreservation can significantly affect the cryopreservation success of potato shoot tips.     

Impact of light-emitting diode irradiation on photosynthesis,phytochemical composition and mineral element content of lettuce cv. Grizzly

Light-emitting diodes (LEDs) are a promising technology with a potential to improve the irradiance efficiency, light quality, and the light spectrum for increasing plant yield and quality. In this experiment, we investigated the impacts of various LED light qualities, including 100% red, 100% blue, 70% red + 30% blue, and 100% white, on the growth and photosynthesis, phytochemical contents, and mineral element concentrations in lettuce (Lactuca sativa L. cv. ‘Grizzly’) in comparison to normal greenhouse conditions. Photon flux of 300 µmol m^?2 s^?1 was provided for 14 h by 120 LEDs set on a 60 cm × 60 cm sheet of aluminum platform in the growth chambers, where plants were grown for 60 d. Fresh mass per plant was significantly higher when grown under 100% blue and 70% red + 30% blue LEDs compared to the other environments including greenhouse conditions. Phytochemical concentrations and a nutritive value of lettuce were also significantly affected by the light treatments. Chlorophyll and carotenoid concentrations increased in the plants grown under 70% red + 30% blue LEDs compared to those grown in the greenhouse. Vitamin C content was 2.25-fold higher in the plants grown under 100% blue LEDs compared to those grown in the greenhouse. Higher photosynthesis and maximal quantum yield of PSII photochemistry were also observed in the plants treated with LED lights. The application of LED light led to the elevated concentrations of macro-and micronutrients in lettuce possibly because of the direct effect of LED light and lower stress conditions in the growth chambers compared to the greenhouse. Although the mechanism of the changes in lettuce grown under LED is not well understood, the results of this study demonstrated that LED light could be used to enhance the growth and nutritional value of lettuce in indoor plant production facilities.     

Effects of light quality on growth and development of protocorm-like bodies of <Emphasis Type="Italic">Dendrobium officinale</Emphasis> in vitro

The effect of light quality on protocorm-like bodies (PLBs) of Dendrobium officinale was investigated. PLBs of D. officinale were incubated under a number of different light conditions in vitro, namely: dark conditions; fluorescent white light (Fw); red light-emitting diodes (LEDs); blue LEDs; half red plus half blue [RB (1:1)] LEDs; 67% red plus 33% blue [RB (2:1)] LEDs; and 33% red plus 67% blue [RB (1:2)] LEDs. Growth parameters, number of shoots produced per PLB, chlorophyll concentration and carotenoid concentration were measured after 90 days culture. The percentage of PLBs producing shoots was 85% under blue LEDs. In contrast, the percentage of PLBs producing shoots was less than 60% under dark conditions, fluorescent white light and red LEDs. The number of shoots produced per PLB was more than 1.5 times greater under blue LEDs, RB (1:1) LEDs and RB (1:2) LEDs than those cultured under other light treatments [dark, Fw, red LEDs and RB (2:1)]. Chlorophyll and carotenoid concentrations were significantly higher under blue LEDs and different red plus blue LED ratios, compared to other light treatments (dark, Fw and red LEDs). Blue LEDs, Fw, and RB (1:2) LEDs produced higher dry matter accumulations of PLBs and shoots. This study suggests that blue LEDs or RB (1:2) LEDs could significantly promote the production of shoots by protocorm-like bodies of D. officinale and increase the dry matter of PLBs and the accumulation of shoot dry matter in vitro.     

Growth responses of marigold and salvia bedding plants as affected by monochromic or mixture radiation provided by a Light-Emitting Diode (LED)

The effects of light generated by monochromic blue, red or mixed radiation from a fluorescent lamp (FL) with light emitting diodes (LEDs) (blue, red, or far-red) on growth and morphogenesis of marigold and salvia seedlings were investigated and the responses compared with those of plantlets grown under a broad spectrum conventional fluorescent lamp (a 16 h photoperiod per day). Dry weight of marigold seedlings was significantly increased in monochromic red light (R), fluorescent light plus red LED (FLR) or fluorescent light (FL) but reduced when monochromic blue light (B) was used, whereas in salvia dry weight was significantly greater under fluorescent light plus blue LED (FLB), fluorescent light plus red LED (FLR) and fluorescent light plus far-red LED (FLFr) as compared to other treatments. Stem length in marigold was greatest in monochromic blue light, being three times greater than in FLR or FL treatments. In salvia, FLFr increased stem length but this was significantly decreased by R as compared to other treatments. The number of visible flower buds in marigold was much higher in FLR as well as in the control (FL), and it was about five times greater than in B or R. However, the number of open flowers in salvia varied slightly in all the treatments. Different light qualities also influenced the duration of the blooming period in both the species. No flower buds were formed when monochromic B or R was used in salvia and FLFr inhibited flower bud formation in marigold. In comparison with monochromic blue or red light, the number of stomata was greater in mixed radiation of FL with LEDs in both the plants. Our study demonstrates the effectiveness of a LED system for plantlet growth and morphogenesis in space-based plant research chambers.     

Combination of Red and Blue Lights Improved the Growth and Development of Eggplant (Solanum melongena L.) Seedlings by Regulating Photosynthesis

The photosynthesis, photomorphogenesis, and photoperiod processes in plants are regulated according to light intensity and quality. The aim of this study was to investigate the effects of different light qualities on eggplant seedlings and determine the best light quality for growth. The seedlings of eggplant cultivar ‘Jingqiejingang’ were grown under light-emitting diodes (LEDs): white (W, the control), red (R), blue (B), and different ratios of B/R lights (B/R = 1/1, B/R = 1/3, B/R = 1/6, B/R = 1/9). The growth parameters, leaf morphology, photosynthetic performance, chlorophyll fluorescence, and the carbon and nitrogen metabolism in the leaves of eggplant seedlings under different LED light treatments were studied. The results showed that the plant height, leaf development, and photosynthetic characteristics were inhibited by red light but elevated by blue light compared with the control. Conversely, the contents of chlorophyll a, chlorophyll b, and carotenoids were all increased by red light, while decreased by blue light significantly. In addition, the contents of carbohydrates and the activities of nitrogen assimilation enzymes were not or little changed by the monochromatic blue and red light. The combined light of red and blue were more beneficial for growth than the monochromatic light, especially B/R = 1/3 light. Under B/R = 1/3 light, the parameter values of plant growth, leaf development, photosynthetic pigments and characteristics, and carbon and nitrogen metabolism were all maximum. Taken together, combined application lights of red and blue are good practice for the cultivation of eggplant seedlings, and LED B/R = 1/3 light was optimum.

     

不同光质的LED对蝴蝶兰组织培养增殖及生根的影响

以蝴蝶兰(Phalaenopsis ssp.)栽培种绿熊(Green Bear)和大辣椒(Big Chilli)为培养材料, 研究不同光质的发光二极管(LED)组合对组织培养过程中增殖及生根的影响。结果表明, 红光更有利于蝴蝶兰单芽增殖、干重、鲜重以及株高的增加, 但不利于叶片叶绿素的积累; 蓝光有利于叶片叶绿素的积累, 并能提高根系活力; 远红光则对根长和根系活力的增加作用更显著。增殖扩繁阶段的最适LED为暖白, 2种蝴蝶兰芽增殖系数分别比白色荧光灯(对照)高出53.17%和46.37%。生根诱导阶段的最适LED组合为红:蓝:远红=3:6:1, 根长及根系活力均较对照显著增加。该研究结果为LED光源在蝴蝶兰组织培养中的应用奠定了基础。