2021 Vol. 39 No. 4
2021, 39(4): 335-348.
DOI: 10.11913/PSJ.2095-0837.2021.40335
Abstract:
Sporogenesis is a key process during asexual reproduction in pteridophytes. However, the formation of sporocyte and spore coats during sporogenesis and the origin of the lamellar layer and inner exospore are less understood. In the present investigation, we examined the process of sporogenesis in Ophioglossum vulgatum L. using transmission electron microscopy. Results showed that the sporocyte coat enclosed the spore mother cells, which underwent meiosis, with the coat then digested after the second meiotic division. A new spore coat was then formed to enclose each tetrad spore. Within the spore coat, the lamellar layer and inner exospore were formed, indicating that both were derived from spore cytoplasmic material. The spore coat was finally digested, after which the plasmodium directly enclosed each spore and the orbicules in the plasmodium were deposited on the lamellar layer to form the outer exospore. Simultaneously, the endospore was formed under the inner exospore. Lastly, the outermost perispore, which was composed of deeply stained material and membranous structures, was formed to cover the exospore. Our results indicated that the so-called surface coat actually consists of two coats, i.e., the sporocyte coat and the tetrad spore coat, which form individually and show no inheritance relationship. The lamellar layer and inner exospore are formed by spore cytoplasm material. The current study elucidated the formation of the sporocyte and spore coats during meiosis and the origin of exospore material in O. vulgatum, and thus should help improve our understanding of sporogenesis in pteridophytes.
Sporogenesis is a key process during asexual reproduction in pteridophytes. However, the formation of sporocyte and spore coats during sporogenesis and the origin of the lamellar layer and inner exospore are less understood. In the present investigation, we examined the process of sporogenesis in Ophioglossum vulgatum L. using transmission electron microscopy. Results showed that the sporocyte coat enclosed the spore mother cells, which underwent meiosis, with the coat then digested after the second meiotic division. A new spore coat was then formed to enclose each tetrad spore. Within the spore coat, the lamellar layer and inner exospore were formed, indicating that both were derived from spore cytoplasmic material. The spore coat was finally digested, after which the plasmodium directly enclosed each spore and the orbicules in the plasmodium were deposited on the lamellar layer to form the outer exospore. Simultaneously, the endospore was formed under the inner exospore. Lastly, the outermost perispore, which was composed of deeply stained material and membranous structures, was formed to cover the exospore. Our results indicated that the so-called surface coat actually consists of two coats, i.e., the sporocyte coat and the tetrad spore coat, which form individually and show no inheritance relationship. The lamellar layer and inner exospore are formed by spore cytoplasm material. The current study elucidated the formation of the sporocyte and spore coats during meiosis and the origin of exospore material in O. vulgatum, and thus should help improve our understanding of sporogenesis in pteridophytes.
2021, 39(4): 349-357.
DOI: 10.11913/PSJ.2095-0837.2021.40349
Abstract:
We combined morphological characters and molecular markers (ITS and RPB2) to study the phylogeny of Cryptocarya species in China, and briefly discussed the causes of species diversity. Results showed that both morphological and molecular evidence supported the division of Cryptocarya species in China into two groups according to their leaf venation characters:i.e., triplinerved leaf group and pinninerved leaf group. Furthermore, Hainan, Yunnan, Guangxi, and Guangdong may be the "cradles" of species differentiation, with more than 90% of Chinese Cryptocarya species distributed in these areas. The morphological characters of most Cryptocarya species in China were very similar, and there were no significant differences in their molecular sequences. This may be due to recent rapid radiation of the species.
We combined morphological characters and molecular markers (ITS and RPB2) to study the phylogeny of Cryptocarya species in China, and briefly discussed the causes of species diversity. Results showed that both morphological and molecular evidence supported the division of Cryptocarya species in China into two groups according to their leaf venation characters:i.e., triplinerved leaf group and pinninerved leaf group. Furthermore, Hainan, Yunnan, Guangxi, and Guangdong may be the "cradles" of species differentiation, with more than 90% of Chinese Cryptocarya species distributed in these areas. The morphological characters of most Cryptocarya species in China were very similar, and there were no significant differences in their molecular sequences. This may be due to recent rapid radiation of the species.
2021, 39(4): 358-366.
DOI: 10.11913/PSJ.2095-0837.2021.40358
Abstract:
Encalypta asiatica J. C. Zhao & L. Li, an endemic species of China, was first discovered in Hebei Province in 2006 and has not been reported since then. From 2012 to 2020, the bryophytes in Tibet have been investigated and collected by our research group and several specimens of E. asiatica were identified. In this paper, the morphological characteristics of E. asiatica were observed in detail. Transverse section of calyptra and capsule stoma were described for the first time:transverse section of calyptra is composed of 1-2 layers of thick-walled cells and 1-2 layers of transparent parenchymal cells; capsule surface is densely covered by stoma from top to bottom. MaxEnt model was used for analyzing the potential distribution of E. asiatica in Tibet under the current climate scenario. Results show that E. asiatica has a potential distribution area of 2.84×105 km2, is mainly distributed in the high-altitude Nagqu and Qamdo, and the annual maximum NDVI (Normalized difference vegetation index) and precipitation of the driest quarter are the most important environment factors to determine its distribution.
Encalypta asiatica J. C. Zhao & L. Li, an endemic species of China, was first discovered in Hebei Province in 2006 and has not been reported since then. From 2012 to 2020, the bryophytes in Tibet have been investigated and collected by our research group and several specimens of E. asiatica were identified. In this paper, the morphological characteristics of E. asiatica were observed in detail. Transverse section of calyptra and capsule stoma were described for the first time:transverse section of calyptra is composed of 1-2 layers of thick-walled cells and 1-2 layers of transparent parenchymal cells; capsule surface is densely covered by stoma from top to bottom. MaxEnt model was used for analyzing the potential distribution of E. asiatica in Tibet under the current climate scenario. Results show that E. asiatica has a potential distribution area of 2.84×105 km2, is mainly distributed in the high-altitude Nagqu and Qamdo, and the annual maximum NDVI (Normalized difference vegetation index) and precipitation of the driest quarter are the most important environment factors to determine its distribution.
2021, 39(4): 367-378.
DOI: 10.11913/PSJ.2095-0837.2021.40367
Abstract:
Morphology and ultra-structure of anther cap in nine Dendrobium species from China were investigated using microscopy and scanning electron microscopy (SEM). Results showed that color, size, shape, and ultra-structure of anther cap varied from species to species. There were three kinds of anther caps:yellow, white, and purple, which were corresponding with those of sepals and petals in each species. Anther cap shapes could be classified into prolate-type and hemisphere-type based on the ratio of the polar to the equatorial axis. SEM revealed four types of ornamental decoration on the outer wall of anther cap, namely, flat-smooth, flat-striated, papillae-striated and papillae-smooth. Morphological and ultra-structural characteristics of anther cap were significantly different in the nine investigated species. Some relationships were supported by comparative anther morphology. (1) Sect. Dendrobium was both paraphyletic and polyphyletic. (2) D. thyrsiflorum Rchb., was closely related to D. densiflorum Lindl. ex Wall. (3) D. gratiosissimum Rchb. F and D. wardinaum Warner were part of the same sister group, which formed a main clade (G4,Pendulum group) with D. lituiflorum Lindl. in Sect. Dendrobium.
Morphology and ultra-structure of anther cap in nine Dendrobium species from China were investigated using microscopy and scanning electron microscopy (SEM). Results showed that color, size, shape, and ultra-structure of anther cap varied from species to species. There were three kinds of anther caps:yellow, white, and purple, which were corresponding with those of sepals and petals in each species. Anther cap shapes could be classified into prolate-type and hemisphere-type based on the ratio of the polar to the equatorial axis. SEM revealed four types of ornamental decoration on the outer wall of anther cap, namely, flat-smooth, flat-striated, papillae-striated and papillae-smooth. Morphological and ultra-structural characteristics of anther cap were significantly different in the nine investigated species. Some relationships were supported by comparative anther morphology. (1) Sect. Dendrobium was both paraphyletic and polyphyletic. (2) D. thyrsiflorum Rchb., was closely related to D. densiflorum Lindl. ex Wall. (3) D. gratiosissimum Rchb. F and D. wardinaum Warner were part of the same sister group, which formed a main clade (G4,Pendulum group) with D. lituiflorum Lindl. in Sect. Dendrobium.
2021, 39(4): 379-388.
DOI: 10.11913/PSJ.2095-0837.2021.40379
Abstract:
We examined the geographical distribution ranges and floral traits of Oreocharis and used nuclear ITS1,ITS2 and chloroplast trnL-trnF sequences of 58 Oreocharis species to construct a phylogenetic tree. We then analyzed the adaptation and evolution of floral traits based on the above data. Results showed the Oreocharis could be separated into two clades. Clade A was mainly distributed in Southwest China and predominantly showed yellow corollas with four stamens; Clade B was mainly distributed in South and Southeast China and predominantly showed purple corollas, with several species evolving two stamens. Corolla evolution from zygomorphy to actinomorphy was also detected. All four Hainan-endemic Oreocharis taxa originated from a common ancestor with bright yellow and radial corollas, later evolving orange and bilateral corollas. Geographical isolation, soil heterogeneity, and divergent selection on diverse bee pollinators were identified as key factors in the evolution and diversity of floral traits in Oreocharis.
We examined the geographical distribution ranges and floral traits of Oreocharis and used nuclear ITS1,ITS2 and chloroplast trnL-trnF sequences of 58 Oreocharis species to construct a phylogenetic tree. We then analyzed the adaptation and evolution of floral traits based on the above data. Results showed the Oreocharis could be separated into two clades. Clade A was mainly distributed in Southwest China and predominantly showed yellow corollas with four stamens; Clade B was mainly distributed in South and Southeast China and predominantly showed purple corollas, with several species evolving two stamens. Corolla evolution from zygomorphy to actinomorphy was also detected. All four Hainan-endemic Oreocharis taxa originated from a common ancestor with bright yellow and radial corollas, later evolving orange and bilateral corollas. Geographical isolation, soil heterogeneity, and divergent selection on diverse bee pollinators were identified as key factors in the evolution and diversity of floral traits in Oreocharis.
2021, 39(4): 389-397.
DOI: 10.11913/PSJ.2095-0837.2021.40389
Abstract:
Amygdalus tangutica (Batal.) Korsh. is a native shrub species with high ecological and economic value found in the arid valley area of Southwest China. Here, we surveyed arid valley sites along the Minjiang River from the Maoxian to Songpan counties. We recorded 47 survey points where A. tangutica was abundant. Among these points, five plots were established to investigate community structure. Six shrub quadrats and 12 herb quadrats were investigated in each plot. To examine vegetative and reproductive characteristics, four sites were selected, with 20 shrubs randomly selected at each site. Variables of shrub and ramet growth (e.g., age, height, basal diameter, canopy area, branch number) and reproduction (e.g., number of fruits and fresh weight of fruit) were determined. Results showed that:(1) A. tangutica formed communities with high species richness (43-55 species/24 m2) and was widely distributed in the arid valley sites along the Minjiang River. (2) An average of 8.83 ±2.25 fruits were found on each shrub. (3) An average of 7.38 ±0.46 sprouts were found on each shrub, with 25.68% of sprouts within the age range of 5-10 years. The ratio of fruit weight to vegetative organ weight was only (0.69 ±0.16)%, indicating weak sexual reproduction capacity. (4) Growth and fruiting parameters were significantly correlated, and fruit number was significantly affected by age and height. Our results suggest that A. tangutica has adapted to the arid valley environment by producing sprouts. However, resource conservation is urgently needed.
Amygdalus tangutica (Batal.) Korsh. is a native shrub species with high ecological and economic value found in the arid valley area of Southwest China. Here, we surveyed arid valley sites along the Minjiang River from the Maoxian to Songpan counties. We recorded 47 survey points where A. tangutica was abundant. Among these points, five plots were established to investigate community structure. Six shrub quadrats and 12 herb quadrats were investigated in each plot. To examine vegetative and reproductive characteristics, four sites were selected, with 20 shrubs randomly selected at each site. Variables of shrub and ramet growth (e.g., age, height, basal diameter, canopy area, branch number) and reproduction (e.g., number of fruits and fresh weight of fruit) were determined. Results showed that:(1) A. tangutica formed communities with high species richness (43-55 species/24 m2) and was widely distributed in the arid valley sites along the Minjiang River. (2) An average of 8.83 ±2.25 fruits were found on each shrub. (3) An average of 7.38 ±0.46 sprouts were found on each shrub, with 25.68% of sprouts within the age range of 5-10 years. The ratio of fruit weight to vegetative organ weight was only (0.69 ±0.16)%, indicating weak sexual reproduction capacity. (4) Growth and fruiting parameters were significantly correlated, and fruit number was significantly affected by age and height. Our results suggest that A. tangutica has adapted to the arid valley environment by producing sprouts. However, resource conservation is urgently needed.
2021, 39(4): 398-406.
DOI: 10.11913/PSJ.2095-0837.2021.40398
Abstract:
Robinia pseudoacacia L. and Hippophae rhamnoides L. are two main tree species used in the artificial afforestation of the Loess Plateau. In the present study, the decomposition of the foliar litter of these two species was examined under different nitrogen (N) deposition. Specifically, a six-month indoor litter decomposition experiment was carried out under control and simulated N deposition (5, 10, and 20 gN ·m-2·yr-1) to detect the effects on litter decomposition and nutrient release. Results showed that:(1) 5 and 10 g·m-2·yr-1 N deposition (LN and MN) significantly accelerated the decomposition of R. pseudoacacia litter, with the MN treatment being more significant. All N deposition treatments significantly inhibited the decomposition of H. rhamnoides litter, and 20 g·m-2·yr-1 N deposition (HM) exhibited a more significant inhibitory effect on the first half of decomposition. (2) The LN and HN treatments significantly inhibited the release of N from R. pseudoacacia litter, while the LN and MN treatments inhibited the release of phosphorus (P); MN accelerated the release of N from H. rhamnoides litter, while HN treatment induced significant inhibition. All N deposition treatments markedly reduced the release of P from H. rhamnoides litter. In general, high-intensity N deposition exhibited stronger inhibitory effects on litter nutrient release. (3) Differences in the litter substrate quality (i.e., carbon (C), N, P, and condensed tannin contents and lignin to N ratio) and the intensity of N deposition were key factors affecting the decomposition of litter and the release of N and P, and there were significant interactions between these two factors.
Robinia pseudoacacia L. and Hippophae rhamnoides L. are two main tree species used in the artificial afforestation of the Loess Plateau. In the present study, the decomposition of the foliar litter of these two species was examined under different nitrogen (N) deposition. Specifically, a six-month indoor litter decomposition experiment was carried out under control and simulated N deposition (5, 10, and 20 gN ·m-2·yr-1) to detect the effects on litter decomposition and nutrient release. Results showed that:(1) 5 and 10 g·m-2·yr-1 N deposition (LN and MN) significantly accelerated the decomposition of R. pseudoacacia litter, with the MN treatment being more significant. All N deposition treatments significantly inhibited the decomposition of H. rhamnoides litter, and 20 g·m-2·yr-1 N deposition (HM) exhibited a more significant inhibitory effect on the first half of decomposition. (2) The LN and HN treatments significantly inhibited the release of N from R. pseudoacacia litter, while the LN and MN treatments inhibited the release of phosphorus (P); MN accelerated the release of N from H. rhamnoides litter, while HN treatment induced significant inhibition. All N deposition treatments markedly reduced the release of P from H. rhamnoides litter. In general, high-intensity N deposition exhibited stronger inhibitory effects on litter nutrient release. (3) Differences in the litter substrate quality (i.e., carbon (C), N, P, and condensed tannin contents and lignin to N ratio) and the intensity of N deposition were key factors affecting the decomposition of litter and the release of N and P, and there were significant interactions between these two factors.
2021, 39(4): 407-414.
DOI: 10.11913/PSJ.2095-0837.2021.40407
Abstract:
Rosa chinensis ‘Viridiflora’ is a valued Chinese garden rose cultivar and represents an important rose germplasm resource, in which the petals, stamens, and pistils are converted into sepal-like organs (i.e., sepalody). Expression of the RcAG gene in flower tissues of the R. chinensis ‘Viridiflora’ and ‘Old Blush’ varieties was analyzed by real-time quantitative polymerase chain reaction (PCR). Results showed that the expression level of RcAG was down-regulated in R. chinensis ‘Viridiflora’. To explore the reason for its down-regulation, the promoter sequences of RcAG were cloned in ‘Viridiflora’ and ‘Old Blush’, respectively. Results showed that the two promoter sequences contained TATA-box, TATC-box, and MBS cis-elements. Notably, MRE and Circadian were specifically found in the RcAG promoter in ‘Viridiflora’, while the TCT motif was only found in ‘Old Blush’. Furthermore, double sulfite sequencing technology was used to analyze promoter methylation. Results showed that all four CpG sites in the promoter region of ‘Viridiflora’ were methylated, and the degree of methylation was much higher than that of ‘Old Blush’. Our findings suggest that the down-regulation of the RcAG gene in ‘Viridiflora’ may be related to its promoter cis-elements and methylation.
Rosa chinensis ‘Viridiflora’ is a valued Chinese garden rose cultivar and represents an important rose germplasm resource, in which the petals, stamens, and pistils are converted into sepal-like organs (i.e., sepalody). Expression of the RcAG gene in flower tissues of the R. chinensis ‘Viridiflora’ and ‘Old Blush’ varieties was analyzed by real-time quantitative polymerase chain reaction (PCR). Results showed that the expression level of RcAG was down-regulated in R. chinensis ‘Viridiflora’. To explore the reason for its down-regulation, the promoter sequences of RcAG were cloned in ‘Viridiflora’ and ‘Old Blush’, respectively. Results showed that the two promoter sequences contained TATA-box, TATC-box, and MBS cis-elements. Notably, MRE and Circadian were specifically found in the RcAG promoter in ‘Viridiflora’, while the TCT motif was only found in ‘Old Blush’. Furthermore, double sulfite sequencing technology was used to analyze promoter methylation. Results showed that all four CpG sites in the promoter region of ‘Viridiflora’ were methylated, and the degree of methylation was much higher than that of ‘Old Blush’. Our findings suggest that the down-regulation of the RcAG gene in ‘Viridiflora’ may be related to its promoter cis-elements and methylation.
2021, 39(4): 415-423.
DOI: 10.11913/PSJ.2095-0837.2021.40415
Abstract:
Genetic diversity and genetic structure of Semiliquidambar cathayensis Hung T. Chang were analyzed using 15 EST-SSR primers. Results revealed that its genetic diversity was high (He=0.816), and that genetic variation mainly existed within populations (76.63%), although the genetic differentiation coefficient among different regions was slightly high (Fst=0.176). The 17 populations could be divided into seven gene banks. We found that the genetic background was complex and the gene heterozygosity was high. However, the genetic structure of the populations were unstable, and four populations (40%) experienced bottleneck events. We showed that S. cathayensis maintained relatively rich genetic variation and had high evolutionary potential. Habitat fragmentation and its endangerment caused by breeding system and human disturbance might be the main causes for the formation of the current geographical distribution pattern and population genetic structure.
Genetic diversity and genetic structure of Semiliquidambar cathayensis Hung T. Chang were analyzed using 15 EST-SSR primers. Results revealed that its genetic diversity was high (He=0.816), and that genetic variation mainly existed within populations (76.63%), although the genetic differentiation coefficient among different regions was slightly high (Fst=0.176). The 17 populations could be divided into seven gene banks. We found that the genetic background was complex and the gene heterozygosity was high. However, the genetic structure of the populations were unstable, and four populations (40%) experienced bottleneck events. We showed that S. cathayensis maintained relatively rich genetic variation and had high evolutionary potential. Habitat fragmentation and its endangerment caused by breeding system and human disturbance might be the main causes for the formation of the current geographical distribution pattern and population genetic structure.
2021, 39(4): 424-432.
DOI: 10.11913/PSJ.2095-0837.2021.40424
Abstract:
We analyzed the impact of two days of high-temperature treatment on the leaf photosystem properties of potted seedlings of two mangrove species, i.e., cold-tolerant Kandelia obovata Sheue, H. Y. Liu & J. Yong and heat-tolerant Bruguiera gymnorrhiza (L.) Savigny, from two geographical populations in Guangxi, China (lower latitude) and Okinawa, Japan (higher latitude). The xanthophyll cycle components and chlorophyll-a and -b contents were measured. The leaf photosystemⅠ(PSⅠ) and photosystemⅡ(PSⅡ) activities were measured using a Dual-PAM-100 system. Results showed that high temperature significantly reduced the maximum photochemical efficiency (Fv/Fm) of PSⅡ in both species. The Fv/Fm values showed less decrease in the lower latitude populations than in the higher latitude populations, and less decrease in B. gymnorrhiza than in K. obovata seedlings. The P700 oxidation-reduction state (Pm) showed less decrease in the lower than higher latitude populations. The leaf non-photochemical quenching (NPQ) showed a greater increase in the lower latitude populations than in the higher latitude populations. The xanthophyll pool size (V + A + Z) and de-epoxidation ratio (A + Z)/(V + A + Z) increased following heat treatment. A greater increase was observed in the lower latitude populations than in the higher latitude populations. In addition, the (A + Z)/(V + A + Z) ratio was negatively correlated with Fv/Fm, but positively correlated with NPQ. Compared with other hardy habitats, such as savannas and Mediterranean woodlands, mangroves had the largest xanthophyll pool size. On the second day of recovery, Fv/Fm was still at 0.69 in the high-latitude K. obovata seedlings, indicating irreversible photoinhibition of PSⅡ, while all seedlings maintained a higher de-epoxidation ratio and NPQ for photosystem protection. In conclusion, the lower latitude populations showed higher adaptability to heat stress, which was partly due to strong photoprotection through the xanthophyll cycle, and there was a tradeoff between cold- and heat-tolerance between species and populations. This study revealed a novel heat tolerance mechanism in mangrove species, which has implications for their physiological responses to future changing climate.
We analyzed the impact of two days of high-temperature treatment on the leaf photosystem properties of potted seedlings of two mangrove species, i.e., cold-tolerant Kandelia obovata Sheue, H. Y. Liu & J. Yong and heat-tolerant Bruguiera gymnorrhiza (L.) Savigny, from two geographical populations in Guangxi, China (lower latitude) and Okinawa, Japan (higher latitude). The xanthophyll cycle components and chlorophyll-a and -b contents were measured. The leaf photosystemⅠ(PSⅠ) and photosystemⅡ(PSⅡ) activities were measured using a Dual-PAM-100 system. Results showed that high temperature significantly reduced the maximum photochemical efficiency (Fv/Fm) of PSⅡ in both species. The Fv/Fm values showed less decrease in the lower latitude populations than in the higher latitude populations, and less decrease in B. gymnorrhiza than in K. obovata seedlings. The P700 oxidation-reduction state (Pm) showed less decrease in the lower than higher latitude populations. The leaf non-photochemical quenching (NPQ) showed a greater increase in the lower latitude populations than in the higher latitude populations. The xanthophyll pool size (V + A + Z) and de-epoxidation ratio (A + Z)/(V + A + Z) increased following heat treatment. A greater increase was observed in the lower latitude populations than in the higher latitude populations. In addition, the (A + Z)/(V + A + Z) ratio was negatively correlated with Fv/Fm, but positively correlated with NPQ. Compared with other hardy habitats, such as savannas and Mediterranean woodlands, mangroves had the largest xanthophyll pool size. On the second day of recovery, Fv/Fm was still at 0.69 in the high-latitude K. obovata seedlings, indicating irreversible photoinhibition of PSⅡ, while all seedlings maintained a higher de-epoxidation ratio and NPQ for photosystem protection. In conclusion, the lower latitude populations showed higher adaptability to heat stress, which was partly due to strong photoprotection through the xanthophyll cycle, and there was a tradeoff between cold- and heat-tolerance between species and populations. This study revealed a novel heat tolerance mechanism in mangrove species, which has implications for their physiological responses to future changing climate.
2021, 39(4): 433-445.
DOI: 10.11913/PSJ.2095-0837.2021.40433
Abstract:
Three different types of sweet potato (Ipomoea batatas (L.) Lam.) were selected as test materials and five nitrogen ratio treatments were established according to three nitrogen forms. Treatments were carried out at 15, 25, and 35 d after planting seedlings. The nitrogen content in different organs, activity of functional leaf nitrogen metabolism enzymes, and expression of enzyme-regulated genes of I. batatas were determined. Results showed that in the same growth period, nitrogen accumulation in plants under the N4 and N5 treatments was significantly higher than that under other treatments; in the early stage of I. batatas growth and development, nitrogen content in the leaves first decreased and then increased, whereas nitrogen content in the stem, fibrous and enlarged roots, and whole plant increased steadily. Moreover, N4 treatment significantly increased the activities of NR, GS, and GDH, while N3 treatment significantly increased the activity of GOGAT. Furthermore, NR activity increased with the increase in the proportion of nitrate nitrogen in the fertilizer. NR activity-related genes were up-regulated when the proportion of nitrate nitrogen increased in the fertilizer. GS and GOGAT-related genes were up- and down-regulated, respectively, by N4 and N5 treatments. Amide nitrogen had no significant effect on the regulation genes of nitrogen metabolism-related enzymes in the early stage. These results imply that in the early stage of I. batatas growth and development, the combined application of nitrate nitrogen and ammonium nitrogen can significantly increase nitrogen accumulation, metabolic enzyme activity, and regulatory gene expression. The nitrogen:nitrate nitrogen:amide nitrogen ratio of 1:2:0 is the best combined application under the experimental conditions.
Three different types of sweet potato (Ipomoea batatas (L.) Lam.) were selected as test materials and five nitrogen ratio treatments were established according to three nitrogen forms. Treatments were carried out at 15, 25, and 35 d after planting seedlings. The nitrogen content in different organs, activity of functional leaf nitrogen metabolism enzymes, and expression of enzyme-regulated genes of I. batatas were determined. Results showed that in the same growth period, nitrogen accumulation in plants under the N4 and N5 treatments was significantly higher than that under other treatments; in the early stage of I. batatas growth and development, nitrogen content in the leaves first decreased and then increased, whereas nitrogen content in the stem, fibrous and enlarged roots, and whole plant increased steadily. Moreover, N4 treatment significantly increased the activities of NR, GS, and GDH, while N3 treatment significantly increased the activity of GOGAT. Furthermore, NR activity increased with the increase in the proportion of nitrate nitrogen in the fertilizer. NR activity-related genes were up-regulated when the proportion of nitrate nitrogen increased in the fertilizer. GS and GOGAT-related genes were up- and down-regulated, respectively, by N4 and N5 treatments. Amide nitrogen had no significant effect on the regulation genes of nitrogen metabolism-related enzymes in the early stage. These results imply that in the early stage of I. batatas growth and development, the combined application of nitrate nitrogen and ammonium nitrogen can significantly increase nitrogen accumulation, metabolic enzyme activity, and regulatory gene expression. The nitrogen:nitrate nitrogen:amide nitrogen ratio of 1:2:0 is the best combined application under the experimental conditions.
2021, 39(4): 446-456.
DOI: 10.11913/PSJ.2095-0837.2021.40446
Abstract:
Tea (Camellia sinensis (L.) O. Kuntze) is one of the most important non-alcoholic beverages in the world. With the continuous development of genetic transformation technology and strong demand for highly resistant and high-quality C.sinensis varieties, direct improvement of C. sinensis through genetic transformation has attracted increasing attention. In this paper, the characteristics and research status of various genetic transformation methods of C. sinensis are reviewed. The main problems with current genetic transformation technology and the main factors affecting genetic transformation of C. sinensis are discussed. In addition, the prospects of de novo meristem induction from in-vivo technology in the genetic transformation of C. sinensis are also considered.
Tea (Camellia sinensis (L.) O. Kuntze) is one of the most important non-alcoholic beverages in the world. With the continuous development of genetic transformation technology and strong demand for highly resistant and high-quality C.sinensis varieties, direct improvement of C. sinensis through genetic transformation has attracted increasing attention. In this paper, the characteristics and research status of various genetic transformation methods of C. sinensis are reviewed. The main problems with current genetic transformation technology and the main factors affecting genetic transformation of C. sinensis are discussed. In addition, the prospects of de novo meristem induction from in-vivo technology in the genetic transformation of C. sinensis are also considered.