Non-structural carbohydrate (NSC) dynamics in different bamboo types underlie the different management practices of bamboo plantations. The changes in moisture, soluble sugars, and starch content in response to phenological variations in different types of bamboo were measured to reveal the NSC dynamics in different bamboo forests for high yield. It was reported for the first time that new leaves of monopodial bamboo started sprouting after the completion of branching, while sympodial bamboo extended new leaves and branches simultaneously. NSC accumulation for shooting lasted about eight months for monopodial bamboo but only a short interval of two to three months for sympodial bamboo. The moisture content in different types of bamboo showed a similar trend of increasing from March to July and then decreasing until the coming January. From March to May, particularly in March, irrigation was required for the shooting of monopodial bamboo, whereas the shoot buds in sympodial bamboo showed sprouting, branching, and leafing. Total NSCs in different bamboo types remained relatively high in March, gradually decreased to the lowest in July, and then increased continuously until the coming January. Average soluble sugar and starch contents showed the same trend as the total NSCs in different types of bamboo. During the period from March to July, large amount of photoassimilates were required for shooting and height growth and then for branching and leafing in monopodial bamboo. Abundant photoassimilates were also required for branching, leafing, and shoot bud differentiation, as well as for subsequent shoot germination in sympodial bamboo. Thus, fertilizer application to both monopodial and sympodial bamboo plantations should be scheduled in early May and late July. Given the moisture, soluble sugar, starch, and total NSC content, January was the best season for harvesting monopodial bamboo for high production and future growth, whereas for sympodial bamboo, November was the best season.
Reasonable management could produce the good growth of bamboo plants. There are few studies in bamboo that integrate phenology and ecophysiological traits; in this case, water relations, photosynthetic rates and carbohydrate content in different organs of Neosinocalamus affinis were determined. The moisture content was easily affected by the local precipitation and showed a similar trend in leaves and branches, with the highest values in July and August, but did not vary significantly between vegetative phenological stages in culms. The emergence and growth of shoots caused an apparent decrease in the moisture content of 1-year culms. NSC content showed a similar trend in culms and branches in classes of different ages and decreased progressively from March through November and then increased in the following months. Net photosynthetic rate and transpiration pull showed the highest values in July and then decreased constantly, which implied that a great deal of water was consumed for photoassimilate synthesis. The net photosynthetic rates of leaves were significantly affected by the water status of culms in the dry season, but correlated significantly only with the leaf water content in the wet season for the sufficient water supply. The transpiration pulls, water potential and sap flow rates revealed the water status of culms better than the water content of culms. The shoot germination and growth of N. affinis were more dependent on the photoassimilate accumulation in the early stage from May to July. There was no real dormancy period for N. affinis due to its apparent photoassimilate accumulation and water flow in January. This suggested that proper irrigation was essential during leaf and branch extension during the dry season.
The moisture, ash, and silicon content, as well as the phytolith morphotype and concentration in the tissue-cultured, seed-cultured, and grafted seedling leaves of Dendrocalamus brandisii were determined to investigate the differences in silicon uptake and phytolith morphology in the leaves from different rearing methods. The results showed that ash, silicon content, and phytolith concentration were higher in the mature leaves. Tissue-cultured seedlings had a significantly higher moisture content than grafted seedlings. Ash and silicon demonstrated the same order of grafted seedlings > tissue-cultured seedlings > seed-cultured seedlings. The highest phytolith concentration was found in tissue-cultured seedlings. The phytolith morphotypes in D. brandisii seedling leaves raised by different methods were identical and grouped into eight morphotypes. The phytolith assemblage was characterized by a high frequency of bilobate and saddle, accounting for more than 60%, whereas the morphotypes of elongate, blocky, flabellate, and circular phytoliths accounted for the smallest proportion, normally all below 4.5%. The phytolith size demonstrated an increasing trend in the maturing leaves. The sizes of bilobate, saddle, and acute phytoliths expanded the fastest in tissue-cultured seedling leaves, implying rapid growth of the cell in tissue-cultured seedlings. Accordingly, the tissue-cultured seedlings contained more silicon and phytoliths of larger sizes, which could be a better choice of stock supply for establishing large-scale plantations. If the stock of the seed-cultured and grafted seedlings is to be used, silicon fertilizer application is an optimal option to boost seedling growth.
Silicon plays a positive role in plant growth and physiological activities; however, silicon fertilizer application in bamboo remains limited. This study explored the silicon accumulation and photosynthetic capacity of Dendrocalamus brandisii in response to sodium silicate (SS) foliar application across vegetative phenological stages. The results showed that August (shooting stage) and May (branching and leafing stage) were the critical periods for silicon accumulation. SS significantly enhanced the net photosynthetic rate (Pn), chlorophyll content, and photosystem activity (Fv/Fm, Fv′/Fm′), particularly in August and May. Correlation analysis revealed that silicon content was significantly positively correlated with photosynthetic parameters (Pn, chlorophyll a/b) and photoassimilate accumulation (soluble sugar, starch), confirming that silicon optimized leaf light capture and carbon assimilation capacity by promoting phytolith formation. This research provides a theoretical foundation for the application of silicon fertilizers in bamboo forest cultivation.
This study investigated the effects of the foliar application of sodium silicate (SS) on phytolith formations in Dendrocalamus brandisii (Munro) Kurz. leaves by analyzing the phytolith concentration, morphological parameters, and assemblage compositions across leaves of varying ages and different phenological stages. The results showed that SS significantly increased the phytolith concentration in D. brandisii leaves, showing a trend of old leaves > mature leaves > young leaves. The concentration of phytoliths was the highest at the late shooting stage (November) and the lowest at the dormancy stage (January). August (shooting stage) and May (branching and leafing stage) were the critical periods for phytolith formation and the size and morphological variation. Sodium silicate significantly increased the proportion of saddle, bilobate, and stomatal phytoliths, which might help optimize the silicified structure of leaf epidermal cells and enhance the leaf resistance and light energy utilization efficiency. The results help clarify the mechanism of phytolith formation in different phenological periods of D. brandisii and provide a theoretical basis for the efficient use of silicon fertilizers in bamboo cultivation.
Bamboo propagation and seed collection are severely limited by a protracted and unpredictable flowering cycle. Dendrocalamus hamiltonii Nees et Arn. ex Munro was renowned for its delectable, bitter-free bamboo shoots, making it an exceptional choice for culinary purposes, which has significant economic value in China. To date, no fruit has been collected, and there are currently no comprehensive studies available on the floral morphology and embryology of D. hamiltonii. The morphological and anatomical characteristics of floral organs were described, and the developmental process of male and female gametophytes was elucidated, through anatomical observation. It was found that the floret of D. hamiltonii was composed of one lemma, palea, pistil, and six stamens, but lacked lodicules. The single ovule, possessing a parietal placenta, was anatropous and featured a double integument. The floral organs showed normal in external morphology, whereas male and female gametophyte development was abnormal, such as pollen grain shrinkage, hollow anther chambers, and underdeveloped ovules, which might be the important factors of its low seed setting rate. This study provided important information on the developmental stages of D. hamiltonii flowers and offered a theoretical basis for understanding the low seed setting rate of bamboo.