Search Results (3)

Date palm (Phoenix dactylifera L.) production relies on the availability of viable and physiologically active pollen during female flowering, making pollen storage an important strategy to overcome flowering asynchrony and ensure effective artificial pollination. In this study, we systematically reviewed and quantitatively synthesized the effects of pollen storage conditions on pollen physiological quality and reproductive performance in date palm. Following PRISMA guidelines, 22 experimental studies were identified in the qualitative synthesis, and comparable quantitative datasets were used for meta-analysis. Acetocarmine staining, the most commonly used method for assessing pollen stainability across studies, was selected as the standardized indicator of pollen stainability. Multilevel random-effects meta-regression models were applied to evaluate temporal deterioration patterns over storage periods of up to 24 months, while standardized forest plot meta-analyses were used to estimate pooled effects after 12 months of storage. The results revealed a strong temperature-dependent decline in pollen physiological quality. Acetocarmine stainability declined by −6.41, −3.10, −2.62, and −2.24% month⁻¹ under ambient, refrigerated, mild freezing, and moderate freezing conditions, respectively, whereas germination declined by −6.77, −1.86, −3.14, −1.09, and −1.05% month⁻¹ under ambient (23–25 °C), refrigerated (4–5 °C), mild freezing (−5 °C), moderate freezing (−20 °C), and deep freezing (−80 °C) conditions, respectively. After 12 months of storage, stainability, germination, and fruit set were significantly reduced relative to fresh pollen. In contrast, pollen storage had no significant effect on final fruit weight, suggesting that pollen deterioration primarily affects fertilization success rather than subsequent fruit development. The available evidence suggests that low-temperature storage represents the most effective strategy for preserving date palm pollen functionality. Refrigerated storage around 4 °C appears to provide a reliable and accessible option for short- to medium-term pollen preservation, whereas freezing conditions may be advantageous for longer storage periods when moisture control and thawing procedures are properly managed. Full article

Asynchronous flowering between male and female date palms (Phoenix dactylifera L.) makes pollen storage a practical necessity for growers, especially for cultivars like ‘Mejhoul’, which require artificial pollination. This study examined the stainability of pollen as an indicator of cytoplasmic integrity, from four male date plant pollen donor genotypes (‘Mejhoul’, ‘Deglet Nour’, ‘Khadrawy’, and ‘Zahidi’) stored at 4 °C for different durations (fresh, one-year, and two-year storage) and their effects on fruit set and physical fruit characteristics of the Mejhoul cultivar in Mexico. Pollen stainability was assessed in vitro using 1% acetocarmine. Fruit and seed set percentages were evaluated as indicators of the practical effectiveness of stored pollen under field conditions, but not as direct measures of viability. Results showed that fresh pollen exhibited the highest stainability (91.2–95.6%), followed by one-year-stored pollen (59.4–68.3%), and two-year-stored pollen (38.8–45.4%). Fruit set percentages were highest with fresh pollen (63.8–81.7%), decreasing with storage duration. ‘Deglet Nour’ pollen consistently showed superior compatibility with ‘Mejhoul’ females. Physical fruit characteristics (weight, length, diameter) and seed traits were minimally affected by reduced pollen stainability, indicating that there were enough viable grains for effective pollination. The study also observed Metaxenia and Xenia effects, where pollen genotypes influenced fruit and seed size. Overall, these findings suggest that pollen stored at 4 °C for short and medium terms can be used in Mejhoul production, but longer storage significantly reduces efficacy, recommending sub-zero temperatures for extended preservation. Full article

Commercially, leguminous crops (Fabaceae) are the second most important group of cultivated plants, just after grasses (Poaceae). This study focuses on the analysis of pollen development and stainability in two species belonging to the Fabaceae family: Vicia faba L. and Lupinus angustifolius L. Morphological analysis of the anthers at various stages of flower development allowed us to trace the processes of microsporogenesis and microgametogenesis. Nine different cell staining protocols with diverse mechanisms of action, including acetocarmine, Alexander’s dye, aniline blue in lactophenol, Calcein AM, FDA, MTT, TTC, Lugol’s iodine, and aceto-orcein, were tested for their suitability in assessing the viability of microspores as well as pollen grains in both species. Among the applied dyes, four allowed for the discrimination between viable and nonviable microspores in V. faba, and six dyes allowed for this in L. angustifolius. For mature pollen grains, all dyes enabled differentiation between viable and nonviable cells in both species. The highest viability indications for V. faba microspores were obtained with acetocarmine (94.6%), while for mature pollen, aniline blue in lactophenol, MTT, and aceto-orcein yielded the highest viability indications (90.8–96.3%). In L. angustifolius, the highest percentages of viable microspores (64.9–66.5%) were obtained with the acetocarmine, aniline blue in lactophenol, and TTC dyes. For mature pollen, the highest viability indications (83.4%–92.9%) were obtained with acetocarmine, aniline blue in lactophenol, Lugol’s iodine, and aceto-orcein. The viability of V. faba pollen grains in an in vitro germination test showed that the highest pollen germination (61.3%) was observed on the BK medium (rich in minerals with 10% sucrose). In L. angustifolius, the highest pollen germination was observed on the media containing boric acid and 5% sucrose (70.5%) and on the medium containing 10% sucrose only (74.2%). Full article