- Research
- Open access
- Published:
Stomata variation in the process of polyploidization in Chinese chive (Allium tuberosum)
BMC Plant Biology volume 23, Article number: 595 (2023)
Abstract
Background
Stomatal variation, including guard cell (GC) density, size and chloroplast number, is often used to differentiate polyploids from diploids. However, few works have focused on stomatal variation with respect to polyploidization, especially for consecutively different ploidy levels within a plant species. For example, Allium tuberosum, which is mainly a tetraploid (2n = 4x = 32), is also found at other ploidy levels which have not been widely studied yet.
Results
We recently found cultivars with different ploidy levels, including those that are diploid (2n = 2x = 16), triploid (2n = 3x = 24), pseudopentaploid (2n = 34–42, mostly 40) and pseudohexaploid (2n = 44–50, mostly 48). GCs were evaluated for their density, size (length and width) and chloroplast number. There was no correspondence between ploidy level and stomatal density, in which anisopolyploids (approximately 57 and 53 stomata/mm2 in triploid and pseudopentaploid, respectively) had a higher stomatal density than isopolyploids (approximately 36, 43, and 44 stomata/mm2 in diploid, tetraploid and pseudohexaploid, respectively). There was a positive relationship between ploidy level and GC chloroplast number (approximately 44, 45, 51, 72 and 90 in diploid to pseudohexaploid, respectively). GC length and width also increased with ploidy level. However, the length increased approximately 1.22 times faster than the width during polyploidization.
Conclusions
This study shows that GC size increased with increasing DNA content, but the rate of increase differed between length and width. In the process of polyploidization, plants evolved longer and narrower stomata with more chloroplasts in the GCs.
Background
Stomata have attracted the attention of scientists for a long time due to their significance in plant productivity. A great deal of knowledge related to the morphology, structure, development, and physiology of stomata has been collected [1,2,3]. Nevertheless, there are still many unanswered questions regarding the origin and evolution of stomata in plants [4, 5]. To explore the problems of stomatal origin, some scholars have studied the stomata of plant fossil materials [6]. However, the available fossil material is limited and can only explore the divergence of bryophytes and tracheophytes [7]. For the evolution of stomata in plants, some findings have shown that the appearance of stomata is a special structure formed by the pressure of changing environment [8, 9]. Some scholars believe that stomata are ancient structures that had diversified by the Early Devonian [5, 10]. In the process of plant evolution, polyploidization is an important evolutionary feature. Many studies have shown that most green plants, especially flowering plants have one or more events of whole genome duplication in their ancestry [11,12,13]. However, few works have focused on stomatal morphological variation in the process of polyploidization. We believe that research stomatal variation during plant polyploidization has important reference value for the study of stomatal origin and evolution.
At present, stomatal morphological variation studies between diploids and polyploids mainly include the density per unit area of epidermis, GC size and number of chloroplasts in GCs [14,15,16]. Polyploidization is considered an important mechanism of plant adaptation to the changing environment by these studies. Because of these morphological variations many physiological functions of plants were affected in polyploids. For example, polyploids use soil water more efficiently, resulting in higher drought resistance [17, 18]. There are differences in CO2 use efficiency between diploids and polyploids, which is of great significance for how to select better adapted crops in today’s increasing greenhouse effect [19]. Therefore, understanding stomatal changes in polyploids could have broader implications for plant adaptation and evolution.
In many plant species, stomatal density has often been used as a morphological marker for identifying ploidy level [20, 21]. A negative relation was observed between the stomatal density and ploidy level. However, in some species, such as Hibiscus syriacus, stomatal density cannot be used as an indicator to estimate ploidy level [22]. The number of chloroplasts in GCs has also generally been used as a marker for estimating the ploidy level of a given plant. There is a positive relationship between genome size and chloroplast number [23,24,25]. GC size has also been used as a characteristic to estimate the ploidy level of many plants. GC length has been shown to have a positive correlation with genome size [26, 27]. However, little attention has been given to GC width in plants with different ploidy levels [28].
Allium tuberosum is a perennial herbaceous plant species belonging to the Liliaceae family. This species is commonly called Chinese chive and is cultivated on a large scale in China, Japan, Korea, Vietnam and India [29]. It is used as a vegetable as well as a spice. It is also used as a cure for hypertension due to its antimicrobial and carminative properties [30]. Almost all Chinese chive varieties and landraces are autotetraploids with a chromosome number of 2n = 4x = 32 [13] and display a high degree of diplosporous apomixis with pseudogamous seed development [31]. Except in the case of tetraploids, different ploidy levels of Chinese chive, such as diploidy [29] and hexaploidy [32], have been discovered. These findings suggested that the reproduction of Chinese chives may vary, addition to parthenogenesis. At present, few works have focused on exploring the different ploidy levels of Chinese chives, and no further development and utilization of these materials has been conducted.
In this study, 420 cultivars were used as materials to screen individuals with different ploidy levels. Flow cytometry combined with chromosome counting was used to determine the ploidy level. Stomal characteristics, including the density, size (length and width) and chloroplast number in the GCs, were observed and measured. Stomatal variation in the evolutionary process of polyploidization was explored and discussed.
Results
Estimation of ploidy levels of each cultivar by flow cytometry
Ploidy levels were inferred by flow cytometry analyses, as shown in Fig. 1. The results showed that 10 individuals of one cultivar that were chosen randomly had the same ploidy level. Among them, one diploid (as the internal reference, Fig. 1a-d), two triploid (Fig. 1a), one pentaploid (Fig. 1c), one hexaploid (Fig. 1d) and 415 tetraploid cultivars were screened (Fig. 1b). Compared with the cultivars with the other ploidy levels, the pentaploid and hexaploid cultivars exhibited a wider and lower peak according to the data.
Determination of ploidy level by chromosome counting
Chromosome counts showed that the diploid chromosome number was 2n = 2x = 16 (Fig. 2a), the triploid chromosome number was 2n = 3x = 24 (Fig. 2b), and the tetraploid chromosome number was 2n = 4x = 32 (Fig. 2c). The pentaploids had 34–42 chromosomes, most of which had 40 chromosomes (Fig. 2d-f). The hexaploids had 44–50 chromosomes, and most had 48 chromosomes (Fig. 2g-i). Given these facts, we named the pentaploids and hexaploids pseudopentaploids and pseudohexaploids, respectively. The chromosome counting results corresponded to the flow cytometry detection results.
The Chinese chive diploid is characterized by a harder, erect and twisted leaf blade (Fig. 3a). In our study, two triploids, which had wide and long leaf characteristics, were screened (Fig. 3b). Indeed, tetraploids have abundant external characteristics, but most are similar to those shown in Fig. 3c. In this study, we mainly chose cultivar 791 as the representative tetraploid, which is planted largely in China. Compared with the cultivars with other ploidy levels, the pseudopentaploids and pseudohexaploids seem to have thicker leaves (Fig. 3d and e). For these cultivars, except for the diploids, the cultivars with different ploidy levels cannot be distinguished from each other by morphological characteristics alone (Fig. 3f).
Comparison of stomatal density among different ploidy levels of Chinese chive
The stomata of the Chinese chive consisted of two similarly sized cells that were shaped like the kidneys (Fig. 4a-e, Fig. 5a). The average number of stomata per unit area of the diploid (36.16 ± 8.09 stomata/mm2) was lower than that of the others (Fig. 4a), while the triploids had the highest density of stomata (57.00 ± 8.11 stomata/mm2) (Fig. 4b). The results showed that anisopolyploid plants, such as triploid and pseudopentaploid plants (53.11 ± 5.99 stomata/mm2), had a higher density than isopolyploid plants, such as diploid (36.16 ± 8.09 stomata/mm2), tetraploid (43.49 ± 5.13 stomata/mm2) and pseudohexaploid (44.08 ± 6.83 stomata/mm2) plants (Fig. 4f). Comparison analysis suggested that the density of GCs differed markedly among different ploidy levels of Chinese chives (p = 0.000). Multiple comparison analysis suggested that there was no significant difference between tetraploids and pseudohexaploids in stomatal number per area, which differed markedly from those of the other cultivars with different ploidy levels.
Comparison of length and width of GCs among Chinese chives of different ploidy levels
The stomatal length and width data are shown in Fig. 5a. The results showed that GCs of different sizes were present within a cultivar. In general, the GC length and width of different cultivars showed a positive correlation with ploidy level (Fig. 5b and c), suggesting the possibility of using this method to distinguish ploidy levels in Chinese chives. Stomatal length and width increased as the ploidy level increased, although there were some overlaps of their values among the different ploidy levels. The increasing trend was more obvious for the length than for the width (Fig. 5b and c). The increase in length was approximately 1.22 times faster than that of the width in the process of polyploidization (Fig. 5d).
In these cultivars, the shortest GC length was 36.223 μm in the diploids, and the longest was 74.727 μm in the pseudohexaploids. The average GC lengths from small to large were 44.799 ± 3.293 μm (diploid), 49.319 ± 3.000 μm (triploid), 52.151 ± 3.476 μm (tetraploid), 56.193 ± 3.947 μm (pseudopentaploid) and 60.325 ± 4.706 μm (pseudohexaploid). The results of our comparative analysis suggested that the length of the stomata differed markedly among Chinese chive cultivars with different ploidy levels.
The variation trend of the GC width was the same as that of the length. The shortest occurred for the diploids (36.935 ± 2.369 μm), and the longest occurred for the pseudohexaploids (43.281 ± 2.756 μm), followed by the triploids (37.929 ± 2.090 μm), tetraploids (39.213 ± 1.813 μm) and pseudopentaploids (42.742 ± 2.699 μm) between the diploids and pseudohexaploids. The results of our comparison analysis suggested that the width of stomatal GCs differed markedly among different ploidy levels of Chinese chive.
Comparison of GC chloroplast numbers among different ploidy levels of Chinese chive
The GC chloroplast number in Chinese chives with different ploidy levels is shown in Fig. 6. The results showed that the average chloroplast number increased as the ploidy level increased, in which diploids had the fewest chloroplasts (44.64 ± 6.42). The pseudohaxaploids had the most chloroplasts in their GCs (90.23 ± 14.04).
Comparison analysis suggested that the chloroplast number of GCs differed markedly among different ploidy levels of Chinese chives (p = 0.000). Multiple comparison analysis suggested that there was no significant difference between diploids and triploids in terms of chloroplast number, which differed markedly from the results of the other cultivars with different ploidy levels (Table 1).
However, the average number of chloroplasts per unit area of GCs did not increase as the ploidy level increased, in which pseudohaxaploids had the maximum number of chloroplasts in their GCs (0.041 ± 0.006/μm2). Multiple comparison analysis suggested that there was no significant difference between triploids and tetraploids in chloroplast number in the unit area of GCs, which differed markedly from those of the other cultivars (Table 2).
Discussion
In many plant species, stomatal density has often been used as a morphological marker for identifying ploidy level. A negative relation has been observed between stomatal density and ploidy level in some plant species [20, 21, 29]. Lattier et al. [22] reported that measurements of stomatal density revealed a sharp decline in average density from the 4 × cytotype to the 5 × cytotype but no significant difference among the 5x, 6x, and 8 × cytotypes. In our study, anisopolyploids (3 × and 5x) had a higher stomatal density than isopolyploids (2x, 4 × and 6x). In addition, diploids had the lowest rather than the greatest stomatal density, suggesting that stomatal density has no negative relation with ploidy level in Chinese chives.
Some research results have shown that reduced stomatal density results in increased water-use efficiency and drought tolerance [33, 34]. Some researchers have even suggested using genetic manipulation of stomatal density to protect future crop yields [35]. Using the stomatal density to estimate the drought tolerance of plants may be a reliable method. Plants with higher ploidy levels should have a higher drought tolerance if there is a negative relation between stomatal density and ploidy level. This has been confirmed by many plant polyploids having numerous advantages over their diploid relatives, including a greater tolerance for poor soils and drought conditions [36, 37]. For Chinese chives, more work should be done to estimate the environmental tolerance for different ploidy levels. In our study, diploid plants had the lowest density of GCs, which may have resulted in stronger drought resistance. However, this trait is less widely distributed in nature. There may be many reasons for this result, as we have seen the diploid external of Chinese chive (Fig. 3a). These plants may contain more fiber due to the hard leaf blade, which influences the taste, resulting in few people growing it. With respect to Chinese chive, tetraploids are the most widespread in nature. The relatively low density of GCs may have played a part in the process of polyploidization. Chinese chives are cultivated vegetables that are mainly influenced by human activity. Therefore, taste and yield are the main influencing factors considered.
Unlike those of many monocots, the stomata of Chinese chives are formed in defined rows or files along the adaxial and abaxial epidermis, with each stoma consisting of two kidney-shaped GCs. For one species, a higher ploidy level is expected to result in a larger cell size, since it has a higher DNA content. Many studies have shown positive associations between ploidy level and stomatal length [22, 26, 27]. This relationship was also verified in our study. There is some overlap among the different ploidy levels of Chinese chives. There were no significant differences among diploids (21.529 μm), triploids (21.050 μm) and tetraploids (21.589 μm) in the range of variation in the length of GCs (Table 3). However, compared with the other types, pseudopentaploids (25.371 μm) and pseudohexaploids (30.079 μm) showed a greater range of variation in the length of GCs (Table 3). This phenomenon may be associated with the unstable DNA content of pseudopentaploids and pseudohexaploids. For GC width, pseudopentaploids (17.180 μm) and pseudohexaploids (18.970 μm) also had a larger range of variation, while tetraploids had the smallest range (Table 4).
One study showed that not only the length but also the width increased as the ploidy level increased. However, the relationship between length and width is still unclear. In this research, we found that the stomatal length displayed a larger increase than the width as the ploidy level increased, suggesting that the GCs did not increase in equal proportion as the ploidy level increased. Therefore, throughout evolution, stomata do not increase equally in terms of length and width in the process of polyploidization (Fig. 7a). During this process, the length increases more than the width, which results in long and narrow stomata at higher ploidy levels (Fig. 7b). Polyploidy is a major driver of evolution in plants. In their evolutionary history, angiosperms have undergone several polyploidization events [11, 38]. In the process of polyploidization events, GCs become larger but have an elongated structural appearance; this could make stomatal closure and opening efficient, resulting in a higher rate of gas exchange in polyploids. At the same time, this longer and narrow pore structure could effectively prevent the entrance of many foreign materials, such as dust and microorganisms.
Epidermal cells cannot photosynthesize because chloroplasts are not present, but in most plant species, GCs contain photosynthetically active chloroplasts [39,40,41,42]. Further studies suggested that the main function of GC chloroplasts is the storage of starch instead of photosynthesis, which influences the balance of the sugar solution for opening GCs [3]. Therefore, the number of GC chloroplasts directly affects the efficiency of the opening and closing of stomata. In our study, the average number of chloroplasts per unit area of GCs did not increase as the ploidy level increased, although the size of GCs increased in this process. It is necessary to pay attention to the efficiency of stomata among these cultivars in a future study. The GC chloroplast number could be used for the detection of hybrids and estimation of ploidy level [43]. Many studies of approximately 80 species, variants and hybrids have revealed that the average GC chloroplast number in leaves or cotyledons ranges from 2.8 to 40.0 for diploids and 5.0 to 73.5 for tetraploids [23, 43]. Furthermore, whole-genome duplication in plants has caused an approximately 1.7-fold increase in GC chloroplast number [24]. In our study, approximately 44.6 and 51.6 chloroplasts were present in the GCs of diploid and tetraploid Chinese chives, respectively (Table 2), suggesting that in Chinese chives, tetraploids could not have originated from the direct duplication of diploids.
Conclusions
The results of the present study highlight that plants have evolved longer and narrower stomata with more chloroplasts in GCs in the process of polyploidization. This study will provide a reference for the study of stomatal morphological changes during plant evolution. It can also be helpful for the study of the adaptability mechanism of plant polyploids to the environment and the utilization of polyploids.
Materials and methods
Materials
A total of 420 cultivars were used in this study, and 10 individuals were chosen randomly for every cultivar. Most cultivars were collected from different regions of China by breeders. All sample collection was permitted by the related department. After years of planting and selecting many collected germplasms, cultivars were formed by division and vegetative propagation. All the materials were located in the resource nursery of the Institute of Agricultural Sciences of Pingdingshan city, Henan Province, China.
Ploidy analysis by flow cytometry
Every cultivar was derived from the same female parent, and we were confident that the present flow cytometry measurements are reliable and that parthenogenesis was the main method of reproduction.
The ploidy level measurements were conducted using a CyFlow Ploidy Analyzer (Partec, Germany) flow cytometer. 4ˊ,6-Diamidino-2-phenylindole (DAPI) was used as the nuclear dye. A fragment of a young healthy leaf (approximately 20 mg) was chopped using a sharp razor blade. Internal standardization (diploid Chinese chive, 2n = 2x = 16) was chopped together with the detection leaf blades in 800 μL of nuclear extraction solution (45 mM MgCl2, 30 mM sodium citrate, 20 mM 4-morpholinepropane sulfonate, 0.1% (v/v) Triton X-100 (pH 7.0) and then filtered through 40 μm nylon mesh after being incubated at room temperature for 3 min. The suspension of released nuclei was stained with 200 μL of DAPI.
Chromosome counts
The ploidy level of the plantlets was further confirmed by root tip chromosome counting. Excised root tips were incubated in a saturated solution of para-dichlorobenzene for 4 h at 17 °C and then fixed for 24 h in Carnoy’s solution (V100% ethanol:Vglacial acetic acid = 3:1) at 4 °C. Fixed root tips were hydrolyzed in 1 N HCl for 15 min at 60 °C, rinsed three times with distilled water, stained in carbol fuchsin for 3 min and ultimately crushed under a micro cover glass. At least 20 well-spread metaphase plates per root tip were sampled for chromosome counting.
Stomatal parameter measurement
Based on the flow cytometry measurements and chromosome counting of different ploidy levels, we further attempted to find differences in stomata. The width and length of the stomata were measured according to the methods of Šmarda et al. [29]. Length of the GCs measured in longitudinal stoma axis, and the width measured as the largest distance between outer GC walls perpendicularly to the longitudinal stoma axis.
In summer 2020 and 2021, different ploidy level cultivars were grown in the same environment in flower pots. Robust mature leaves for each plant were selected to acquire the lower epidermis peel, which could be removed directly from fresh leaves using blade and tweezers. Abaxial and adaxial epidermal tissues were removed simultaneously due to the narrow leaf bleed of the Chinese chive. The removed epidermis peel was unfolded completely using distilled water on microscope slides. Each slide represented a random leaf sample and was treated as a replicate for further analysis.
Statistics and data analysis
All preparations were viewed using a confocal laser scanning microscope (LSM; Carl Zeiss 880, Germany). Stomatal density was observed by the z-stack scan technique using 405 nm excitation light. Images were captured randomly and processed using image analysis software (ZEN 3.1 Blue Edition, Zeiss, Germany). More than 20 epidermal peels were obtained from every selected material. A minimum of 1000 stomata for every material were measured for GC length and width. A total of 150 GCs were chosen randomly for area measurement for every cultivar. All data were measured via digital image control (DIC) with an LSM. The size (length and width) and area of GCs were measured using distance and contour measurement tools respectively (ZEN 3.1 Blue Edition, Zeiss). Chloroplast GC pairs were also observed by the z-stack scan technique using excitation at 514 nm.
A comparison of the data, including stomatal density and GC length and width, was compared by the Student Newman Keuls Test (S–N-K) method among different ploidy levels. The statistical data were analyzed using IBM SPSS Statistics 19 (IBM, Armonk, NY, USA). GC length and width were also compared, as shown in boxplots using Origin 2019 (OriginLab, Northampton, Massachusetts, USA).
Availability of data and materials
All the data are available in the submitted manuscript.
Abbreviations
- GC:
-
Guard cell
References
Bergmann DC, Sack FD. Stomatal development. Ann Rev Plant Biol. 2007;58:163–81.
Berry JA, Beerling DJ, Franks PJ. Stomata: key players in the earth system, past and present. Curr Opin Plant Biol. 2010;13(3):232–9.
Lim SL, Flütsch S, Liu J, Distefano L, Santelia D, Lim BL. Arabidopsis guard cell chloroplasts import cytosolic ATP for starch turnover and stomatal opening. Nat Commun. 2022;13(1):1–13.
Nunes TD, Zhang D, Raissig MT. Form, development and function of grass stomata. Plant J. 2020;101(4):780–99.
Clark JW, Harris BJ, Hetherington AJ, Hurtado-Castano N, Brench RA, Casson S, Williams TA, Gray JE, Hetherington AM. The origin and evolution of stomata. Curr Biol. 2022;32(11):R539–53.
Masterson J. Stomatal size in fossil plants: evidence for polyploidy in majority of angiosperms. Science. 1994;264(5157):421–4.
Harris BJ, Harrison CJ, Hetherington AM, Williams TA. Phylogenomic evidence for the monophyly of bryophytes and the reductive evolution of stomata. Curr Biol. 2020;30(11):2001–12.
Raven JA. Selection pressures on stomatal evolution. New Phytol. 2002;153(3):371–86.
Isner JC, Olteanu VA, Hetherington AJ, Coupel-Ledru A, Sun P, et al. Short-and long-term effects of UVA on Arabidopsis are mediated by a novel cGMP phosphodiesterase. Curr Biol. 2019;29(15):2580–5.
Chater CC, Caine RS, Fleming AJ, Gray JE. Origins and evolution of stomatal development. Plant Physiol. 2017;174(2):624–38.
Van de Peer Y, Mizrachi E, Marchal K. The evolutionary significance of polyploidy. Nat Rev Genet. 2017;18:411–24.
Chanderbali AS, Jin L, Xu Q, Zhang Y, Zhang J, et al. Buxus and Tetracentron genomes help resolve eudicot genome history. Nat Commun. 2022;13:643.
Heslop-Harrison JS, Schwarzacher T, Liu Q. Polyploidy: its consequences and enabling role in plant diversification and evolution. Ann Bot. 2023;131(1):1–10.
Borges VP, Silveira DG, Costa MADC, Santos-Serejo JAD, Silva SDO. Ploidy estimation and pre-selection of banana autotetraploids after in vitro polyploidy induction. Rev Caatinga. 2023;36:494–501.
Bhadra S, Leitch IJ, Onstein RE. From genome size to trait evolution during angiosperm radiation. Trends Genet. 2023;39:728–35.
Castañeda-Nava JJ, Santacruz-Ruvalcaba F, Barba-González R, González JDJS, De la Cruz Larios L. Evaluation the correlation of ploidy level, leaf size, stomata characteristics and tuber weight in Dioscorea spp. populations from Jalisco, México. Trop Subtrop Agroecosyst. 2023;26(2):1–11.
Mbo Nkoulou LF, Ngalle HB, Cros D, Adje CO, Fassinou NV, Bell J, Achigan-Dako EG. Perspective for genomic-enabled prediction against black Sigatoka disease and drought stress in polyploid species. Front Plant Sci. 2022;13:953133.
Perera-Castro AV, Hernández B, Grajal-Martín MJ, González-Rodríguez ÁM. Assessment of drought stress tolerance of Mangifera indica L. autotetraploids. Agronomy. 2023;13(1):277.
Šmarda P, Klem K, Knápek O, Veselá B, Veselá K, et al. Growth, physiology, and stomatal parameters of plant polyploids grown under ice age, present-day, and future CO2 concentrations. New Phytol. 2023;239(1):399–414.
Yuan S, Liu YM, Fang ZY, Yang LM, Zhuang M, Zhang YY, Sun PT. Study on the relationship between the ploidy level of microspore-derived plants and the number of chloroplast in stomatal guard cells in Brassica oleracea. Agric Sci China. 2009;8(8):939–46.
Ye YM, Tong J, Shi XP, Yuan W, Li GR. Morphological and cytological studies of diploid and colchicine-induced tetraploid lines of crape myrtle (Lagerstroemia indica L). Sci Hortic. 2010;124(1):95–101.
Lattier JD, Chen H, Contreras RN. Variation in genome size, ploidy, stomata, and rDNA signals in Althea. J Am Soc Hortic Sci. 2019;144(2):130–40.
Mochizuki A, Sueoka N. Genetic studies on the number of plastid in stomata. Cytologia. 1955;20(4):358–66.
Butterfass T. Control of plastid division by means of nuclear DNA amount. Protoplasma. 1973;76(2):167–95.
Singsit C, Veilleux RE. Chloroplast density in guard cells of leaves of anther-derived potato plants grown in vitro and in vivo. HortScience. 1991;26(5):592–4.
Beaulieu JM, Leitch IJ, Patel S, Pendharkar A, Knight CA. Genome size is a strong predictor of cell size and stomatal density in angiosperms. New Phytol. 2008;179(4):975–86.
da Silva HA, Scapim CA, Vivas JM, do Amaral AT, Pinto RJ, Mourão KS, Rossi RM, Baleroni AG. Effect of ploidy level on guard cell length and use of stomata to discard diploids among putative haploids in maize. Crop Sci. 2020;60(3):1199–209.
Padoan D, Mossad A, Chiancone B, Germana MA, Khan PS. Ploidy levels in Citrus clementine affects leaf morphology, stomatal density and water content. Theor Exp Plant Phys. 2013;25:283–90.
Sharma G, Gohil RN. Origin and cytology of a novel cytotype of Allium tuberosum Rottl. ex Spreng. (2n= 48). Genet Resour Crop Ev. 2013;60(2):503–11.
Pandey A, Pandey R, Negi KS, Radhamani J. Realizing value of genetic resources of Allium in India. Genet Resour Crop Ev. 2008;55(7):985–94.
Yamashita KI, Nakazawa Y, Namai K, Amagai M, Tsukazaki H, Wako T, Kojima A. Modes of inheritance of two apomixis components, diplospory and parthenogenesis, in Chinese chive (Allium ramosum) revealed by analysis of the segregating population generated by back-crossing between amphimictic and apomictic diploids. Breed Sci. 2012;62(2):160–9.
Kojima A, Nagato Y. Discovery of highly apomictic and highly amphimictic dihaploids in Allium tuberosum. Sex Plant Reprod. 1997;10(1):8–12.
Caine RS, Yin X, Sloan J, Harrison EL, Mohammed U, Fulton T, Biswal AK, Dionora J, Chater CC, Coe RA, Bandyopadhyay A. Rice with reduced stomatal density conserves water and has improved drought tolerance under future climate conditions. New Phytol. 2019;221(1):371–84.
Dunn J, Hunt L, Afsharinafar M, Meselmani MA, Mitchell A, Howells R, Wallington E, Fleming AJ, Gray JE. Reduced stomatal density in bread wheat leads to increased water-use efficiency. J Exp Bot. 2019;70(18):4737–48.
Buckley CR, Caine RS, Gray JE. Pores for thought: can genetic manipulation of stomatal density protect future rice yields? Front Plant Sci. 2020;10:1783.
Rao S, Tian Y, Xia X, Li Y, Chen J. Chromosome doubling mediates superior drought tolerance in Lycium ruthenicum via abscisic acid signaling. Hortic Res. 2020;7:1–18.
Sarr MS, Seiler JR, Sullivan J, Diallo AM, Strahm BD. Drought resistance and gum yield performances in a Senegalia senegal (L.) Britton progeny trial in Senegal. New Forests. 2021;52(6):943–57.
Hörandl E, Oberprieler C, Marhold K, Wagner ND. Evolution and biodiversity of wild polyploids. Front Plant Sci. 2021;1465. https://doi.org/10.3389/fpls.2021.723439.
Outlaw WH Jr, Mayne BC, Zenger VE, Manchester J. Presence of both photosystems in guard cells of Vicia faba L: implications for environmental signal processing. Plant Physiol. 1981;67(1):12–6.
Zemel E, Gepstein S. Immunological evidence for the presence of ribulose bisphosphate carboxylase in guard cell chloroplasts. Plant Physiol. 1985;78(3):586–90.
Gotow K, Taylor S, Zeiger E. Photosynthetic carbon fixation in guard cell protoplasts of Vicia faba L. Evidence from radiolabel experiments. Plant Physiol. 1988;86(3):700–5.
Lawson T, Oxborough K, Morison JI, Baker NR. The responses of guard and mesophyll cell photosynthesis to CO2, O2, light, and water stress in a range of species are similar. J Exp Bot. 2003;54(388):1743–52.
Fujiwara MT, Sanjaya A, Itoh RD. Arabidopsis thaliana leaf epidermal guard cells: a model for studying chloroplast proliferation and partitioning in plants. Front Plant Sci. 2019;10:1403.
Acknowledgements
We are very grateful to the editors and reviewers for their critical evaluation of the manuscript and for providing constructive comments on its improvements.
Funding
This work was financially supported by the Scientific and Technology Project in Henan Province, China (212102110040).
Author information
Authors and Affiliations
Contributions
Peng-qiang Yao: designed research, conducted experiments. Jian-hua Chen: organized tables and pictures. Pei-fang Ma, Li-Hua Xie: conducted experiments. Shi-ping Cheng: designed research, reviewed the paper. All authors have read and agreed to the published version of the manuscript.
Corresponding author
Ethics declarations
Ethics approval and consent to participate
All experimental research on plants including the collection of plant material, complied with relevant institutional, national, and international guidelines and legislation.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Additional information
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary Information
Additional file 1.
Chloroplast number of guard cells in different ploidy levels of Chinese chives.
Additional file 2.
Stomatal number in the area of 850.2μm × 850.2μm of epidermal layer in different ploidy levels of Chinese chives.
Additional file 3.
Stomatal length of different ploidy levels of Chinese chives.
Additional file 4.
Stomatal width of different ploidy levels of Chinese chives.
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.
About this article
Cite this article
Yao, PQ., Chen, JH., Ma, PF. et al. Stomata variation in the process of polyploidization in Chinese chive (Allium tuberosum). BMC Plant Biol 23, 595 (2023). https://doi.org/10.1186/s12870-023-04615-y
Received:
Accepted:
Published:
DOI: https://doi.org/10.1186/s12870-023-04615-y