1Research Institute of Insect Resources, Chinese Academy of Forestry, Bailongsi, Panlong District, Kunming 650233, ChinaFind articles by
1Research Institute of Insect Resources, Chinese Academy of Forestry, Bailongsi, Panlong District, Kunming 650233, ChinaFind articles by
3Key Laboratory of Biodiversity and Biogeography, Kunming Institute of Botany, Chinese Academy of Sciences, No. 132, Lanhei Road, Panlong District, Kunming 650201, ChinaFind articles by
1Research Institute of Insect Resources, Chinese Academy of Forestry, Bailongsi, Panlong District, Kunming 650233, ChinaFind articles by
Breeding system characteristics of woody bamboo species are still little known although this knowledge is important for research on genetic improvement and conservation of bamboo forests. The present study is the first report on variation in breeding system from mass and sporadically flowering bamboo populations. The results demonstrate that two Dendrocalamus species have a mixed mating system with self-compatibility, predominant outcrossing, and no agamospermy. Pollen limitation and scarcity of wild pollinators influence sexual reproduction in sporadically flowering populations of both species.
An understanding of the breeding systems and pollination of agriculturally important plants is critical to germplasm improvement. Breeding system characteristics greatly influence the amount and spatial distribution of genetic variation within and amongst populations and influence the rarity and extinction vulnerability of plant species. Many woody bamboos have a long vegetative period (20–150 years) followed by gregarious monocarpy. Relatively, little is known about their pollination and breeding systems. We studied these characteristics in wild Dendrocalamus membranaceus populations and cultivated Dendrocalamus sinicus populations distributed in the Yunnan Province of China. Floral morphology, flower visitors and breeding system were studied from 2013 to 2015. Both bamboos were protogynous, but flowering periods of florets overlapped providing opportunities for self-pollination amongst florets, especially in D. membranaceus. There was no agamospermy in either species. Seed set of D. sinicus was low (0.42 ± 0.42 %) under natural pollination but higher (8.89 ± 2.55 %) after artificial xenogamy. Seed set of D. membranaceus was higher (7.49 ± 0.82 %) in mass flowering populations and 2.14 ± 0.25 % in sporadically flowering populations. The Asian honeybee Apis cerana could provide cross-pollination of D. membranaceus and D. sinicus, and flower visitation peaked at 1000–1200 h. Pollination limitation due to lack of pollinators or pollen was detected in the cultivated populations of D. sinicus and sporadically flowering populations of D. membranaceus. Pollination limitation was not obvious within mass flowering populations. Hand pollination could significantly increase seed set of these two bamboo species. Dendrocalamus membranaceus and D. sinicus were self-compatible and have a mixed-mating system with outcrossing being pre-dominant. Their seed production was limited by the quantity of pollen and pollinator activity. Honeybees were observed as effective pollinators.
The breeding system is a key component of plant sexual reproduction. Many studies have suggested that the health and maintenance of plant populations is strongly affected by breeding characteristics, such as flower phenology, self-compatibility and the breeding system (Nair et al. 2004; Gan et al. 2013). Understanding the reproductive biology of agriculturally important crops is crucial for developing genetic improvement strategies and establishing appropriate conservation measures (Nair et al. 2004; Rodríguez-Pérez 2005).
We examined the breeding system and pollination of D. membranaceus and D. sinicus, by studying floral characters, flower visitors, and the mating systems found in mass and sporadically flowering populations. Our goals were to determine the breeding system of two woody bamboos and document aspects of the reproductive biology that may be useful for research on genetic improvement and conservation of Dendrocalamus bamboo forests.
Pollinating Bamboo Palm Plants A Guide to Boosting Fruit Production
Having a fruitful bamboo palm plant requires proper pollination. As someone who enjoys growing bamboo palms, I’ve learned the ins and outs of pollinating these tropical beauties over the years. Proper pollination techniques can significantly increase the yield of your bamboo palm. In this comprehensive guide, I’ll walk you through everything you need to know about pollinating bamboo palm plants and maximizing their fruit production.
Understanding Bamboo Palm Pollination
Bamboo palms are dioecious plants meaning they have separate male and female flowers on different plants. For the female plant to produce fruits and seeds its flowers must receive pollen from a male plant. Without cross-pollination from a male plant, the female flowers will simply fall off without yielding any fruits.
Identifying Male and Female Plants
The first step is identifying whether your bamboo palm is male or female. Female bamboo palm flowers are larger and rounded, emerging near the base of the leaves. Male flowers are smaller and slender, growing closer to the top of the leaves.
If your plant hasn’t flowered yet, look for signs of fruit growth to determine its sex. Only pollinated female plants will develop small black berry-like fruits.
Transferring Pollen
Once you’ve identified male and female plants, pollination can begin. I recommend using a clean small brush, cotton swab, or Q-tip to collect pollen from the male flowers. Gently brush this pollen onto the female flowers, focusing on the sticky stigma in the center.
For best results, pollinate in the early morning when flowers are open and most receptive. Repeat every other day during peak flowering. Avoid excessive pollination, as too much competition for nutrients can decrease yields.
Optimal Conditions for High Yields
Along with proper pollination, bamboo palms need adequate care for prolific fruit production. Here are some key tips:
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Bright, indirect light is essential. Rotate the plant if needed.
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Water 1-2 times per week, allowing soil to dry between waterings.
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Apply balanced liquid fertilizer every 2-3 months during spring and summer.
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Maintain warm temperatures between 65°F-80°F.
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Prune out dead leaves and spent flowers to encourage new growth.
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Repot in fresh soil every 2-3 years as needed.
Troubleshooting Common Problems
Yellowing leaves – Overwatering or insufficient drainage
Leaf scorch – Too much sunlight or accumulated salts
Webbing – Spider mites; wipe leaves and apply insecticidal soap
Stunted growth – Underwatering, overwatering, or insufficient light
Few/no fruits – Lack of pollination or only one gender of plant present
By providing proper pollination, care, and growing conditions, your bamboo palm will reward you with a bountiful crop of berries. Pay close attention and intervene early to prevent potential problems. With a little effort, you can reap a prolific harvest from these exotic tropical plants.
Propagating Bamboo Palms
Once your bamboo palm is fruiting, you can harvest the seeds and propagate new plants. Here are some key propagation tips:
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Collect ripe black fruits, remove pulp, and extract seeds
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Plant seeds 1⁄4 inch deep in well-draining potting mix. Maintain warmth and moisture.
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Germination may take 1-12 months due to hard seed coat. Be patient.
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Transplant seedlings when they have 3-4 leaves. Grow on in bright, indirect light.
You can also propagate by dividing existing plants. Cut off offshoots with their own root systems and repot separately. This method is faster than seed propagation.
Choosing the Best Variety
With over 100 species available, there are many excellent bamboo palms to choose from. Here are some of my top recommendations:
Bamboo Palm (Chamaedorea seifrizii) – Hardy, multi-stemmed palm growing 8-10 feet tall. Great screening plant.
Parlor Palm (Chamaedorea elegans) – Compact palm popular as a houseplant. Grows 5-8 feet tall indoors.
Pacaya Palm (Chamaedorea tepejilote) – Giant bamboo palm reaching 10-20 feet tall. Fast growing.
Cat Palm (Chamaedorea cataractarum) – Clumping palm with tropical appeal. Grows 6-8 feet tall.
Hardy Bamboo Palm (Chamaedorea microspadix) – Tolerates cooler temperatures. Silvery green leaves.
Match the variety to your climate, space, and needs. With proper pollination, any of these handsome bamboo palms can become a fruitful addition to your indoor or outdoor space.
Pollinating your bamboo palm correctly is the key to getting it to produce an abundant harvest. Identify male and female plants, manually transfer pollen from male to female flowers, and provide optimal growing conditions. Prevent problems through attentive care and early intervention. Propagate new plants from seeds or divisions. With this guide’s tips in mind, you’ll gain the satisfaction of growing a lush, fruitful bamboo palm.
Floret morphology and development
We considered each bamboo clump as a probable genet and the culms within as ramets of a clone according to McClure (1966). During the full blooming stage of D. membranaceus and D. sinicus, 30 intact fresh florets were selected and measured from every clump surveyed. Floret morphological characters were observed using a ×10 hand lens. Glumes, lemmas, paleas, filaments, anthers and styles of the floret were measured for length and median width (max-width) using vernier calipers. To reveal details of floral development, such as the floral development sequence, 10 pseudospikelets from each flowering culm were observed.
To assess the effects of pollen source on seed set of D. membranaceus and D. sinicus, various pollination experiments were performed in situ during the spring of 2014 and 2015. Because the flowering bamboo clumps will die within one year, we had only one chance to apply the experimental treatments to each flowering bamboo clump. For each clump, at least five flowering culms were selected to study the breeding system. Pollination treatments, performed according to Dafni (1992) and Gan et al. (2013) were conducted as follow: natural control, no emasculation and no bagging; autonomous self-pollination, no emasculation and bagging to test whether pollinators were needed; assisted geitonogamy, emasculation and bagging to test whether geitonogamy was limited; assisted xenogamy, emasculation and bagging to test fertility of outcrossing; natural cross-pollination, emasculation and no bagging to test whether pollen transfer was limited; parthenogenesis test, emasculation, bagging and no pollination by hand to test whether agamospermy may have occurred.
Hand pollination experiments were carried out according to Zych and Stpiczyńska (2012). Pollen was collected from non-dehisced ripe anthers of either the same individual flower (self-pollination) or another flower from three unmarked clumps of the same species that was growing at a distance of at least 5 m (cross-pollination). Pollen was stored in 1.5 mL Eppendorf tubes. All pollen was applied within 4 h to ensure viability. When stigmas were visible, pollen was applied to florets using one sterile brush for each species. Three replicates of 20 pseudospikelets were marked for each treatment. For D. membranaceus, because only the floret at the top of a pseudospikelet was pollinated and eventually developed into a seed, we used only the topmost floret for pollination studies. In D. sinicus, the topmost floret of each pseudospikelet was sterile and most of pseudospikelets only bear one seed from the second floret so we only used the second floret in the hand pollination experiments. Seed set was estimated with the following formula: seed set (%) = total number of seeds/total number of pseudospikelets × 100 %.
The pollen limitation index (L; Larson and Barrett 2000) was used to quantify pollen limitation within a population for each species. The index was calculated as L = 1 – (PN/PS), where PN is the percentage of naturally pollinated seeds and PS is the percentage seed set by supplement cross-pollen. No pollen limitation is indicated in the population if L = 0 (Larson and Barrett 2000).
Flower visitor activities were observed in the field at the peak of flowering in late March of 2014 and 2015, respectively. Observations were conducted simultaneously at three sites for D. membranaceus and D. sinicus from 0800 h to 1600 h on 7 sunny days. For each observation we selected 10 flowering branches each having at least ten blooming pseudospikelets. Representative flower visitors were captured for identification using trap nets. It was recorded if visitors carried D. membranaceus and D. sinicus pollen. Pollinator frequency was expressed as number of visits to florets per hour.
Seed set of the hand pollination experiments was compared by a one-way ANOVA using PROC GLM. When significant differences were found, means were separated by Student–Newman–Keuls (SNK) multiple comparison analysis at P = 0.01 and P = 0.05, respectively. All statistical analyses were performed with SAS (Version 9.2, SAS Institute Inc., Cary, NC).
The statistical significance of pollen limitation was evaluated by Students t test (independent samples) in Excel 2010 (Microsoft Corp., Seattle, WA). Differences were considered to be statistically significant when P ≤ 0.05 and highly significant when P ≤ 0.01.
Both D. membranaceus and D. sinicus bear large-scaled panicles on leafless flower branches ( ), but they differed in floral morphology. In D. membranaceus, 30–70 (minimum and maximum) pseudospikelets form a dense, spiky globose mass at the nodes of flowering branches and this was 2.5–3.5 cm in diameter. Pseudospikelets are flat, ovoid, 10–12 mm long, 2–4 mm wide, yellow green when fresh and straw yellow when withered. Each pseudospikelet comprises 2–4 florets. The floret bears two ovate, apically acute glumes. Lemma is 8–9 mm long, 5–8 mm wide. Palea is membranous, 7–8 mm long, 3–6 mm wide, with two ciliate keels. Stamens protruded from a floret when mature. Filaments are milky white, 10–15 mm long. Anthers are purple, 5–8 mm long. Ovary is ovoid and hairy, and ciliate style is 10–15 mm long with one purple and plumose stigma.
In D. sinicus, 1–6 pseudospikelets form a sparse cluster at each node of flowering branches. Pseudospikelets are flat, narrowly ovoid, 30–45 mm long, 5–8 mm wide, purple when fresh and also straw yellow when withered. Each pseudospikelet contains 6–7 florets. Floret bears two ovate and apically acute glumes. Lemma is 10–25 mm long and 10–15 mm wide. Palea is 12–18 mm long and 6–12 mm wide, membranous, two-keeled, with a two-fid apex. Six stamens protruded from the floret when it matured. Filaments are milky white, 20–35 mm long. Anthers are 8–15 mm long, yellow, with mucronate apices. Ovary is ovoid and hairy, and ciliate style is 20–35 mm long with only one purple and plumose stigma.
March 2013–December 2015 observations revealed that D. membranaceus and D. sinicus bloom at any time of the day but mostly occurred from 8000 h to 1200 h. Both species were protogynous but the maturation of pistils and stamens of different florets can overlap ( ). Typically, extrusion of the stigma from the lemma occurs 4 h earlier than the stamens. In D. sinicus, the flowering duration of a single pseudospikelet (from protrusion of the stigma of the uppermost fertile floret to withering of the stigma of the last maturing floret) lasts up to 30 h, which was 10 h longer than that of D. membranaceus.
Florets in the same pseudospikelet matured at different times. In D. membranaceus, the topmost floret matured first, but the basal florets often degenerated. In D. sinicus, the topmost floret was vestigial, and florets matured sequentially from the second floret downwards, i.e. in a basipetal manner ( ).
Seeds were produced after the geitonogamy and xenogamy fertilization treatments ( ), indicating that D. membranaceus and D. sinicus are self-compatible and outcrossing fertile. However, results from a one-way ANOVA indicated that a highly significant difference of seed set (F17, 36 = 60.43, P < 0.0001) existed between the assisted geitonogamy and assisted xenogamy in five study sites (sites A–E). These sites included mass flowering populations and sporadically flowering populations of D. membranaceus as well as sporadically flowering populations of D. sinicus. This suggests that these two species are pre-dominantly outcrossing (P < 0.01). Seed set from assisted geitonogamy was significantly higher (P < 0.05) than seed set from autonomous self-pollination, and there was no significant difference between natural pollination and autonomous self-pollination and natural cross-pollination ( ), suggesting pollination limitation in those populations. No seeds were obtained with emasculation and bagging, suggesting absence of agamospermy in two bamboo species.
Seed set in D. sinicus was 0.42 ± 0.42 % under natural pollination in sites D and E. After artificial xenogamy, seed set increased 20-fold to 8.89 ± 2.55 %. Seed set of D. membranaceus was relatively higher. Results from a second ANOVA revealed that there was a significant difference between mass flowering (7.49 ± 0.82 %) and sporadically flowering (2.14 ± 0.25 %) populations with natural pollination (F11, 24 = 63.86, P < 0.0001; ). There was also a significant difference in seed set from assisted xenogamy and natural cross-pollination (P < 0.01) between flowering populations of D. membranaceus (F11, 24 = 63.86, P < 0.0001; ), but no significant differences in seed set from autonomous self-pollination and assisted geitonogamy.
Pollen limitation (based on comparison of natural pollination with supplemental pollination) occurred in sporadically flowering natural populations of D. membranaceus as well as in the cultivated stand of D. sinicus. The pollen limitation index (L) values were 0.895 and 0.961, respectively ( ), and the difference was highly significant (P < 0.01) in D. sinicus, which had higher mean seed set with supplemental pollination (10.67 ± 0.82) compared with open pollination (0.42 ± 0.42). In the mass flowering D. membranaceus population there was no significant pollen limitation although seed set under natural population (7.49 ± 0.82) was significantly increased seed set (31.17 ± 0.63) in the supplemented treatment.
| Species | Flowering type | Seed set in the natural pollination (%) | Seed set in the supplemental cross-pollen (%) | Pollen limitation index (L) | Significance test (t test) |
|---|---|---|---|---|---|
| D. membranaceus | Mass | 7.49 ± 0.82 | 31.17 ± 0.63 | 0.760 | – |
| D. membranaceus | Sporadic | 2.14 ± 0.25 | 20.39 ± 1.00 | 0.895 | * |
| D. sinicus | Sporadic | 0.42 ± 0.42 | 10.67 ± 0.82 | 0.961 | ** |
Although both D. membranaceus and D. sinicus were expected to be wind pollinated, insect flower visitors were observed at five study sites. We observed a total of 48 and 82 insect visits to D. membranaceus and D. sinicus flowers, respectively. The Asian honeybee Apis cerana was the most common insect visitor ( ). On sunny days, the mean visitation frequency of A. cerana was 11.5 and 19.5 times per hour for D. membranaceus and D. sinicus, respectively. Visitation frequency peaked from 1000 h to 1200 h for both bamboo species. Thereafter, the number of visiting bees rapidly declined. Cloudy or rainy days also reduced visitation frequency ( ).
Honeybees were often observed visiting more than one flower per clump, and generally had short flight ranges. Most visitors grasped anthers and gathered pollen grains with their forelegs, then transferred grains to their hindlegs and abdomen. At the same time, masses of grains were dispersed into the air, accentuated when more bees visited flowers.
Dendrocalamus membranaceus and D. sinicus are self-compatible but pre-dominantly outcrossing, and no apomixis occurs. The results are consistent with the findings of Venkatesh (1984) and Kitamura and Takayuki (2011) who reported that bamboo species such as Bambusa arundinacea and Sasa cernua, were self-compatible because seed set was observed even with imposed (bagged) isolation and without emasculation. In this study, the seed set from xenogamy and the control was greater than those from autogamy, suggesting that outcrossing is pre-dominant in the breeding system of D. membranaceus and D. sinicus and similar to other bamboos such as those reported by Gan et al. (2013). Higher seed set in the two species from assisted geitonogamy compared with autonomous self-pollination implied that self-fertilization may depend on pollen vectors. The seed set from autonomous self-pollination and assisted geitonogamy were similar in mass and sporadic flowering populations of D. membranaceus, suggesting stable self-fertility. But in D. sinicus, the self-compatibility may be dependent on pollen vectors such as honeybees because bagging experiments confirmed the absence of auto-fertility. These results are similar with those of Johnson et al. (2006) and Blambert et al. (2016). In natural populations of D. membranaceus and D. sinicus, the higher seed set rates in assisted xenogamy treatments reflected a strong tendency for xenogamy and indicated either a lack of pollinators or low pollination efficiency. Self-compatibility may be the evolutionary consequence of lack of pollinators or inadequate pollination (Barrett 1998; Jacquemyn et al. 2005; Blambert et al. 2016).
Pollination of seed plants is an essential step in their sexual reproduction (Memmott et al. 2007). Dendrocalamusmembranaceus and D. sinicus are wind pollinated, as in most woody bamboos such as Phyllostachys pubescens (Cheung et al. 1985), Dendrocalamus strictus (Nadgauda et al. 1993) and Arundinaria gigantea (Gagnon and Platt 2008). However, pollinators such as Apis mellifera, have been observed visiting the flowers of some bamboos (Venkatesh 1984; Nadgauda et al. 1993). Their role in the pollination of bamboos was overlooked because they only seemed to gather pollen in the male phase of flowering and neglected the female phase. As such, they were only considered to be vectors of pollen (Nadgauda et al. 1993). In our study, honeybees at a site visited flowers sequentially and carried pollen away on their hindlegs, increasing the likelihood of transferring pollen from flowers of the same or nearby flowering bamboo clumps. Honeybees may be good pollinators for D. membranaceus and D. sinicus. These two bamboo species may have evolved to release pollen that is available for bee pollination. The time of pollen release may coincide with the peak of their flower visitation activity. Masses of pollen grains were released into the air when bees visited flowers and this would increase the chances for geitonogamy pollination. Our observations suggest that honeybee pollination could augment wind-pollination in D. membranaceus and D. sinicus, similar to study on Phyllostachys nidularia by Huang et al. (2002).
Natural vs. artificial population variation in breeding system
Given the rapid decline of D. membranaceus and D. sinicus populations (Gu et al. 2012; Xie et al. 2016), immediate conservation efforts should be considered to protect their germplasm. The genetic diversity of the species would be at risk of further decline, so both in situ and ex situ conservation measures may be necessary for these species. For D. membranaceus, management of the species could involve enlarging or retaining populations with genetically less-related individuals, i.e. ‘genetic rescue’ (Holmes et al. 2008). Meanwhile, closing the land for reforestation and prohibiting human intrusion would help natural recovery processes in the mass-flowering populations (Xie et al. 2016). Attention should be directed toward the conservation of D. sinicus due to its limited distribution and unsupervised collection of culms (Hui 2004). One practical conservation solution would be to establish more ex situ cultivated stands to meet commercial demands. We should also make a special effort to collect seeds of D. membranaceus and D. sinicus for study. More research is needed to determine whether inbreeding depression is occurring in their flowering populations, especially in the sporadic flowering populations.
This is the first report on variation in breeding system from mass and sporadically flowering bamboo populations. Our results demonstrate that both Dendrocalamus species have a mixed mating system with self-compatibility, pre-dominant outcrossing and no agamospermy. The selfing component may be dependent on a pollen vector for seed setting, particularly in D. sinicus. Reproductive limitations were revealed in the sporadically flowering populations of D. sinicus. Pollen limitation and scarcity of wild pollinators influenced the sexual reproduction of D. membranaceus and D. sinicus. Honeybees may effectively augment wind pollination in sporadically flowering populations of both species.
The research was supported by the Fundamental Research Funds of the Chinese Academy of Forestry (CAFYBB2017ZX001-8), the National Natural Science Foundation of China (31270662), Department of Sciences and Technology of Yunnan Province (2014HB041, 2008OC001).
How to Make Plants Grow FASTER | creative_explained
FAQ
Can you split a bamboo palm?
Does bamboo need to be pollinated?
What is the best fertilizer for bamboo palms?
How often should you water a bamboo palm?
How to grow bamboo palm in pots?
Here is a care guide to help you successfully grow Bamboo Palm in pots: Pot selection: Choose a pot that is slightly larger than the current root ball of the plant. Ensure the pot has drainage holes at the bottom to prevent waterlogging. Soil requirements: Use a well-draining potting mix that is rich in organic matter.
How do you repot a bamboo palm?
Make sure you have a sharp garden knife, potting soil, and a correct-size pot. Water both the existing palm and the new pot with soil. Remove the existing bamboo palm from its pot and carefully cut off an offshoot section, including several stems and their roots. Repot both the original plant and the cutting immediately.
Are bamboo palms easy to grow?
Bamboo palms are stunning, graceful plants that can add a touch of nature to any room or outdoor setting. Not only do they look great, but they’re also easy to grow and care for, making them an ideal plant for both beginner and experienced gardeners.
What kind of soil do bamboo palms need?
Bamboo palms thrive in well-draining soil that is rich in organic matter. In general, a potting mix that contains peat moss, perlite, and/or vermiculite works well for indoor plants, while a soil mix that contains sand and mulch is suitable for outdoor plants.