The balance between growth and defense in response to nearby or canopy shading in heliotropic plants has been deeply understood. However, the adaptive traits developed by shade-tolerant plants through long-term evolution remain unclear. In this study, the typical shade-tolerant medicinal plant Anoectochilus roxburghii was used as the experimental material.(1) Different planting densities were set, including 8 cm(row spacing) × 8 cm(plant spacing), 6 cm × 6 cm, 4 cm × 4 cm, and 2 cm × 2 cm, to monitor the individual plant responses to nearby shading.(2) Different light environments, including blue light∶red light=3∶2(B3R2), blue light∶red light∶far-red light=3∶2∶1(B3R2FR1), blue light∶red light∶far-red light=3∶2∶2(B3R2FR2), and blue light∶red light∶far-red light=3∶2∶4(B3R2FR4), were set to monitor the morphological and physiological changes in plants in response to actual shading conditions. The results showed that:(1) Moderate increases in planting density helped optimize morphological traits such as stem diameter and leaf area. This not only slightly increased biomass but also significantly improved SOD activity in both leaves and stems, as well as lignin content in stems, thereby enhancing the plant's defense capabilities.(2) Increasing the far-red light in the light environment negatively regulated the plant height of A. roxburghii, which was contrary to the typical shade-avoidance response observed in heliotropic plants. However, it significantly enhanced SOD and POD activity in both stems and leaves, as well as lignin content in stems. Furthermore, it reduced the incidence and disease index of stalk rot, effectively defending against biotic stress. Therefore, the shade-tolerant plant A. roxburghii has specific adaptive strategies for shading conditions. Reasonable dense planting or light environment modulation can synergistically improve yield, medicinal quality, and resistance of A. roxburghii. This study provides a theoretical foundation and technical support for optimizing the regional deployment and cultivation strategies of ecological planting for Chinese medicinal materials.
Orchidaceae/genetics* ; Light ; Plant Leaves/physiology* ; Sunlight ; Adaptation, Physiological/radiation effects* ; Plant Proteins/genetics*

Chlorophyll content,leaf mass to per area,net photosynthetic rate and bioactive ingredients of Asarum heterotropoides var. mandshuricum,a skiophyte grown in four levels of solar irradiance were measured and analyzed in order to investigate the response of photosynthetic capability to light irradiance and other environmental factors. It suggested that the leaf mass to per area of plant was greatest value of four kinds of light irradiance and decreasing intensity of solar irradiance resulted in the decrease of leaf mass to per area at every phenological stage. At expanding leaf stage,the rate of Chla and Chlb was 3. 11 when A. heterotropoides var. mandshuricum grew in full light irradiance which is similar to the rate of heliophytes,however,the rate of Chla and Chlb was below to 3. 0 when they grew in shading environment. The content of Chla,Chlb and Chl( a+b) was the greatest value of four kinds of light irradiance and decreasing intensity of solar irradiance resulted in its decreasing remarkably( P<0. 05). The rate of Chla and Chlb decreased but the content of Chla,Chlb and Chl( a+b) increased gradually with continued shading. The maximum value of photosynthetically active radiation appeared at 10: 00-12: 00 am in a day. The maximum value of net photosynthetic rate appeared at 8: 30-9: 00 am and the minimum value appeared at 14: 00-14: 30 pm at each phenological stage if plants grew in full sunlight. However,when plants grew in shading,the maximum value of net photosynthetic rate appeared at about 10: 30 am and the minimum value appeared at 12: 20-12: 50 pm at each phenological stage. At expanding leaf stage and flowering stage,the average of net photosynthetic rate of leaves in full sunlight was remarkably higher than those in shading and it decreased greatly with decreasing of irradiance gradually( P < 0. 05). However,at fruiting stage,the average of net photosynthetic rate of leaves in full sunlight was lower than those in 50% and 28% full sunlight but higher than those in 12% full sunlight. All photosynthetic diurnal variation parameters of plants measured in four kinds of different irradiance at three stages were used in correlation analysis. The results suggested that no significant correlation was observed between net photosynthetic rate and photosynthetically active radiation,and significant negative correlation was observed between net photosynthetic rate and environmental temperature as well as vapor pressure deficit expect for 12% full sunlight. Positive correlation was observed between net photosynthestic rate and relative humidity expect for 12% full sunlight. Significant positive correlation was observed between net photosynthetic rate and stomatal conductance in the four light treatments. Only,in 12% full sunlight,the net photosynthetic rate was significantly related to photosynthetically active radiation rather than related to environmental temperature,vapor pressure deficit and relative humidity. In each light treatment,a significant positive correlation was observed between environmental temperature and vapor pressure deficit,relative humidity as well as stomatal conductance. Volatile oil content was 1. 46%,2. 16%,1. 56%,1. 30% respectively. ethanol extracts was 23. 44%,22. 45%,22. 18%,21. 12% respectively. Asarinin content was 0. 281%,0. 291%,0. 279% and 0. 252% respectively. The characteristic components of Asarum volatile oil of plant in different light treatments did not change significantly among different groups.
Asarum ; physiology ; radiation effects ; Chlorophyll ; analysis ; Photosynthesis ; Plant Leaves ; radiation effects ; Sunlight

To explore the effects of shading and the expression of key enzyme genes on the synthesis and accumulation of Panax japonicus var. major saponins, different shading treatments (0%, 30%,50%) of potted P. japonicus var. major were used as test materials, the expression of three key enzyme genes(CAS,DS,-AS) of leaves and rhizomes in different growth periods of P. japonicus var. major was determined by real-time quantitative PCR, the content of total saponins was determined by ultraviolet spectrophotometry. The results indicated that, in flowering stage, CAS,DS,-AS were highly expressed in the aerial parts of P. japonicus var. major, 30% shading treatment significantly inhibited the expression of CAS in leaves and promoted the expression of DS and -AS in stems, leaves and flowers, it was speculated that the main part of saponin synthesis was leaf in this stage. Both the expression levels of DS and -AS and changes in the content of total saponins in leaves showed a tendency of low-high-low throughout the growth cycle, correlation coefficient analysis showed that there was a positive correlation between them. Compared with control, the expression levels of DS and -AS and the content of total saponins were greatly enhanced under shading treatment, 30% shading treatment significantly promoted the accumulation of total saponins. Therefore, it is suggested that 30% shading treatment should be applied to the artificial cultivation of P. japonicus var. major, which is beneficial to the accumulation and quality improvement of saponins.
Gene Expression Regulation, Plant ; Light ; Panax ; enzymology ; genetics ; radiation effects ; Plant Leaves ; enzymology ; genetics ; Rhizome ; enzymology ; genetics ; Saponins ; analysis

Under different red (R):blue (B) photon flux ratios, the growth performance of rapeseed (Brassica napus L.) is significantly different. Rapeseed under high R ratios shows shade response, while under high B ratios it shows sun-type morphology. Rapeseed under monochromatic red or blue light is seriously stressed. Transcriptomic and proteomic methods were used to analyze the metabolic pathway change of rapeseed (cv. "Zhongshuang 11") leaves under different R:B photon flux ratios (including 100R:0B%, 75R:25B%, 25R:75B%, and 0R:100B%), based on digital gene expression (DGE) and two-dimensional gel electrophoresis (2-DE). For DGE analysis, 2054 differentially expressed transcripts (|log₂(fold change)|≥1, q<0.005) were detected among the treatments. High R ratios (100R:0B% and 75R:25B%) enhanced the expression of cellular structural components, mainly the cell wall and cell membrane. These components participated in plant epidermis development and anatomical structure morphogenesis. This might be related to the shade response induced by red light. High B ratios (25R:75B% and 0R:100B%) promoted the expression of chloroplast-related components, which might be involved in the formation of sun-type chloroplast induced by blue light. For 2-DE analysis, 37 protein spots showed more than a 2-fold difference in expression among the treatments. Monochromatic light (ML; 100R:0B% and 0R:100B%) stimulated accumulation of proteins associated with antioxidation, photosystem II (PSII), DNA and ribosome repairs, while compound light (CL; 75R:25B% and 25R:75B%) accelerated accumulation of proteins associated with carbohydrate, nucleic acid, amino acid, vitamin, and xanthophyll metabolisms. These findings can be useful in understanding the response mechanisms of rapeseed leaves to different R:B photon flux ratios.
Brassica napus/radiation effects* ; Brassica rapa/radiation effects* ; Carbon/chemistry* ; Chloroplasts/radiation effects* ; Computational Biology ; Electrophoresis, Gel, Two-Dimensional ; Gene Expression Regulation, Plant/radiation effects* ; Image Processing, Computer-Assisted ; Light ; Mass Spectrometry ; Metabolic Networks and Pathways ; Nitrogen/chemistry* ; Photons ; Photosystem II Protein Complex/genetics* ; Plant Leaves/radiation effects* ; Plant Proteins/genetics* ; Proteome ; Ribosomes ; Transcription, Genetic ; Transcriptome

Measuring the content of soluble reducing sugar, total sugar, soluble protein, guanosine, alkaloids, and succinic acid of Pinellia ternata tuber were measured by anthrone-sulfuric acid colorimetric method, Coomassie brilliant blue method, RP-HPLC, reverse potentiometric titration, acid dye colorimetry, respectively. The result showed that yellow light could promote the growth and development of P. ternata and increase the content of soluble reducing sugar, total sugar, alkaloids, and succinic acid. Under blue light could promote the content of soluble protein and guanosine. Red and yellow light increased the content of chlorophyll a and chlorophyll b, contrastively blue light reduced the content of chlorophyll a and chlorophyll b. White film through the most uniform spectrum was most conducive to the synthesis of chlorophyll a. As single film, blue film, yellow film were more conducive to the synthesis of chlorophyll a, green film and red film had been relatively beneficial to the synthesis of chlorophyll b. Bulbil formed the largest number and the biggest propagation coefficient of P. ternata under red light showed that it could increase the production of P. ternata under red light.
Carbohydrate Metabolism ; radiation effects ; Chlorophyll ; metabolism ; Light ; Pinellia ; growth & development ; metabolism ; radiation effects ; Plant Leaves ; growth & development ; radiation effects ; Plant Proteins ; chemistry ; metabolism ; Quality Control ; Solubility

OBJECTIVEThe aim of this study was to compare the plant morphological characteristics and photosynthetic physiological characteristics of Paeonia Radix Rubra and Paeonia Radix Alba, and find evidence of whether there are intraspecific variations of Paeonia lactiflora.

METHODWith wild and cultivated P. lactiflora of the roots as asexual reproduction materials for cultivation experiment, morphological index, photosynthetic parameters and photosynthetic pigment content were measured.

RESULTIn the 9 of morphological characteristics between wild and cultivated P. lactiflora, the number of leaf, blade length, the width of leaf and the length of top leaf showed a significant difference. The variances within wild P. lactiflora group were big than those within cultivated P. lactiflora in 8 of morphological characteristics. In photosynthetic physiological characteristics, wild P. lactiflora were significantly higher than cultivated P. lactiflora in Max. net photosynthetic rate (P(max)), light compensation point (LCP), light saturation point(LSP), CO2 saturation point (CSP) and CO2 saturated P(n) (P(m)). And significantly lower than cultivated P. lactiflora in maximum net photosynthetic rate (P(max)), light compensation point (LCP), light in apparent quantum yield (AQY), CO2 compensation point (CCP), carboxylation efficiency (CE) and photosynthetic pigment content.

CONCLUSIONWild and cultivated P. lactiflora have significant difference in morphological characteristics of leaf and photosynthetic physiological characteristics.

Carbon Dioxide ; metabolism ; Light ; Paeonia ; anatomy & histology ; growth & development ; metabolism ; radiation effects ; Photosynthesis ; radiation effects ; Plant Leaves ; anatomy & histology ; growth & development ; metabolism ; radiation effects

OBJECTIVETo study the influences of enhanced UV-B radiation and drought stress on the biomass accumulation and allocation of Fagopyrum dibotrys, and so as to provide a theoretical basis for the cultivation, the protection and use of F. dibotrys.

METHODBy experiment of potted plant, the biomass accumulation and allocation of F. dibotrys were measured under different drought stresses and UV-B radiations.

RESULTIn conditions of adequate water, enhanced UV-B radiation significantly reduced biomass accumulation to root, biomass accumulation to leaves, total biomass accumulation and biomass allocation to root in F. dibotrys, while it could increase biomass allocation to stem. In conditions of moderate drought stress, enhanced UV-B radiation increased biomass accumulation to root, biomass accumulation to stem and biomass accumulation to root. In the conditions of severe drought stress, enhanced UV-B radiation increased biomass accumulation to root, it also could lead in a certain increase to biomass accumulation to stem. Biomass allocation to root, stem and leaves was not sensitive to enhanced UV-B radiation.

CONCLUSIONThe influences of enhanced UV-B radiation in simulation and drought stress on the biomass accumulation and allocation of F. dibotrys were determined by water conditions and different apparatus. Overall, we verified that enhanced UV-B radiation would reduce the influences of biomass accumulation of F. dibotrys by drought.

Biomass ; Droughts ; Fagopyrum ; metabolism ; radiation effects ; Plant Leaves ; metabolism ; radiation effects ; Plant Roots ; metabolism ; radiation effects ; Stress, Physiological ; Time Factors ; Ultraviolet Rays

OBJECTIVETo investigate the photosynthetic characteristics of wildlife tending Alpinia oxyphylla, and provide a theoretical basis for choosing wildlife tending environment and cultivation management.

METHODThe response parameters of the net photosynthetic rate to light intensity, CO2 concentration and photosynthetic characteristics were measured by Li-6400 portable photosynthesis in blossom bud forming stages under different treated conditions.

RESULTThe maximum net photosynthetic rate (Pmax), daily average photosynthetic rate (Pn), apparent quantum efficiency (AQY), apparent carboxylation efficiency (CE), light using efficiency (LUE), and water use efficiency (WUE) were optimal in the wild tending treatment at the light transmission rate of 17.4%-24.1%, beyond the light transmission rate, the photosynthetic capacity utilization of A. oxyphylla would not have a significant increase or be inhibited. The light compensation point (LCP) and light saturation point (LSP) of A. oxyphylla improved with light intensity enhancing. Wildlife tending could enhance the scope of A. oxyphylla to CO2 adaptation.

CONCLUSIONA. oxyphylla as sciophytes, and the optimum light transmission rate for wild tending and cultivating was at 17.4%-24.1%.

Alpinia ; metabolism ; radiation effects ; Carbon Dioxide ; metabolism ; Light ; Photosynthesis ; radiation effects ; Plant Leaves ; metabolism ; radiation effects

OBJECTIVETo study the growth index and physiological index of Tianquan Bergenia purpurascens under different shade conditions (100%, 80%, 60%, 40%, 20%), and investigate its adaptation mechanism to shade environment so that it can provide theoretical basis for cultivation and production.

METHODThe growth index such as the length, the width and the number of new leaves, and leaf area, fresh weight, dry weight and specific leaf weight of the samples which were collected from the beginning of March to late May under different shade conditions were measured. The physiological index including the contents of photosynthetic pigments, MDA, soluble sugar, soluble protein, proline and the activity of SOD were measured all together.

RESULTThe growth and morphological index under light intensity 100%-60% were higher than those under light intensity 40%-20%. And except specific leaf weight, the growth and morphological index were significantly higher under light intensity 60% than those under the other shade conditions; The contents of Chla, Chlb, Chl (a + b) and Car under light intensity 100%-60% were higher than those under light intensity 40%-20%, while Chla/b was higher under light intensity 40%-20%; The activity of SOD, soluble sugar, soluble protein and proline contents were higher under light intensity 100%-60%, while MDA content was higher under light intensity 40%-20%. Chl(a+b) content, soluble sugar content and activity of SOD were the highest under light intensity 60%, but MDA content was the lowest.

CONCLUSIONSixty percent irradiance treatment was the most favorable to the growth of Tianquan B. purpurascens; 100%-80% irradiance treatments were favorable to its growth; 40%-20% irradiance treatment was negative for its growth.

Chlorophyll ; analysis ; metabolism ; Light ; Photosynthesis ; Plant Extracts ; analysis ; metabolism ; Plant Leaves ; chemistry ; growth & development ; metabolism ; radiation effects ; Saxifragaceae ; chemistry ; growth & development ; metabolism ; radiation effects

OBJECTIVETo study the effect of light intensity on photosynthetic characteristics and seedling growth of Prunella vulgaris under different light intensity.

METHODThe seedling of P. vulgaris was shaded with shading net, and relative parameters were measured. The data was statistically processed.

RESULTWith the reducing light intensity, the young plant stems became slender, the leaf long increased. The plant height and net growth under 42% full light condition were significantly higher than those under the other light intensity, chlorophy II and carotenoid contents increased, as well as Chl a/b decreased under low light. Photosynthetic indicators of P(n), T(r) decreased under low light, but CO2 concentration increased, and G(s) content decreases and then increased under 10% full light intensity.

CONCLUSIONP. vulgaris manifested the different plasticity and adaptability under different light intensities. The 42% light intensity was the best and the proper shading would promote the growth of seedlings.

Adaptation, Physiological ; Chlorophyll ; metabolism ; Light ; Photosynthesis ; radiation effects ; Plant Leaves ; growth & development ; radiation effects ; Plant Stems ; growth & development ; radiation effects ; Prunella ; growth & development ; radiation effects ; Seedlings ; growth & development ; radiation effects