Impact of Increased Temperature on Delosperma Cooperi Pollen

Impact of Increased Temperature on Delosperma Cooperi Pollen Eunice Oh The Impact of Increased Temperature due to Global Warming on Pollen Germination of  Delosperma  Cooperi Introduction: There is an ongoing crisis that is beginning to influence ecosystems throughout the world,  which may lead to large  scale  natural disasters due to the rise in temperature from global warming. According to NASA’s Goddard Institute for Space studies,  0.8 °C  have increased around the world since 1880. In addition, the rise in temperature is pervasive and  is  increasing at a faster rate in the last two decades (SITE1). This warming phenomenon can disturb ecosystems  and  lead to extinction in extreme cases.  Such ecosystems are dependent on plant growth and proliferation to sustain itself.  Therefore, an experiment to  observe  the  effects of  a significant  rise in temperature on pollen germination was conducted to predict the adaptability of  Delopsperma  cooperi,  a  common species of  iceplant  grown around the world, to  this phenomenon  . T  Delosperma cooperi  (trailing iceplant) was compared to  Tulbaghia violacea  (society garlic)  to obtain a broader view of how different plants from the same environment would react to a distinct change in temperature.  An increase of 10 °C was chosen as the variable to perform  analysis with the Q10  temperature coefficient.  Pollen is a fine powder that contains microgametophytes of seed plants and produces male gametes. When pollination occurs, the pollen grain  germinates and a tube is produced  as a conduit to transport the male gametes from the stigma to the pistils  of the ovule in flowering plants  (SITE2).   In nature, germination occurs  when the stigma is hydrated from  water  sources (e.g. rain)  . can also be induced  in vitro  using  a  germination media and  the  hanging drop method (SITE 3).  Three replicates were observed the were  analyzed  with  statistics  to  measure the significance of the variable   (via a T-test, and Dixon Q).   The plant’s temperature dependence was quantified with the Q10  temperature coefficient. It was predicted  that the increase in temperature would result in  a significant improvement of  pollen germination rate  and longer pollen tubes than the control  due to  Delosperma  cooperi’s  adaptive traits (quote). Materials and Methods: Germination of  Delosperma  cooperi  was induced in basic germination media, composed of  1mM KCl, 0.1mM CaCl2, 1.6mM H3BO3, 10% glucose,and distilled water. Standard lab  equipments were  used: light  microscope,  garden  gaskets, depression slides, slides warmer, petri dish,  and micropipettes. The light microscope was used under the 10x objective to track the germination process and measure the elongation of pollen tubes. To  accommodate  for  a large sample volume (50 µL  transferred using micropipettes), garden gaskets were employed to extend the capacity of the depression slides.  A  slides warmer  was used to maintain the high temperature environment (37 °C  )  and  wet  petri  dishes were  utilized as germination chambers. The hanging drop method consists  of several steps.   A gasket was placed on top of the slide in order to create an area for the hanging drop to be intact with the cover slide  and held together with grease. The slides were placed in the humidity  chamber to  allow germination and  prevent drying. Two sets of the hanging drops were prepared, one for the higher temperature (37 °C),  and another for the  positive  control  (27 °C  ). The negative control was prepared by observing the pollen without any germination media. Statistical analysis methodology: The  germination  elongation rates were recorded  by sampling five  pollen  tubes from each slide in 30 minutes  intervals, up to 150 minutes.  This data was analyzed  using biostatistics.  A  Dixon  Q test was performed to identify and remove outliers.  The  Dixon Q test  was calculated using the equation, Q= (gap)/(range). The gap refers to the absolute difference between the outlier and the closest number to the outlier  and the range is simply between the smallest and largest values  (CITE). After the elimination of outliers from the Dixon Q test, a student T-Test  (with a 95% confidence interval)  was performed to determine whether the variables were statistically significant in the difference of their elongation rates  using P values  (SITE).  Finally, a  Q10  value was determined from the mean of  elongation  rates.  It was calculated by using the following equation: Q10  = (R2/R1)10/(T2-T1).  Q10  is a unit-less measur ement that  quantify  the change of a biological system  due to temperature change. Results: The purpose of the experiment was to  measure the  elongation rates after every 30 minute interval, 32 points of data were obtained and analyzed.  Overall, the elongation rate  of  Delosperma cooperifor the high  temperature variable was as much as three  times faster  compared to the control  temperature  (0.686  Ã‚ µm/min vs.  0.278 µm/min)  in trial three. The percent germination was  also  noticeably better for the  high temperature variable  versus the control, where  it was  approximately 60% compared to 20%  after 120  minutes from initiation. From the list of data, the  Dixon Q-test result indicated the data point 0.780 µm/min of the higher temperature control as an outlier  with a 95% confidence level. The mean elongation rate for the room temperature was 0.314 µm/min and 0.454 µÃ‚  m/min for the higher temperature control. The student T-Test  yielded  a P value of 0.0447, which indicates  that the result is statistically significant at a 95% confidence interval.   The  Q10  temperature coefficient  for   Delosperma cooperi  was calculated to be  3.59, categorized as a temperature dependent biological system. Figure 1.  The graph shows the average  elongation  rates of  Delosperma  cooperi  at two different  temperatures. The tubule elongation rate was  0.314 µm/min  for the control and  0.454 µm/min  for the variable. Error bars denote one standard deviation  (0.152 µm/min  and  0.177 µm/min, respectively)  above and below the mean. Figure  2. The graph shows the average elongation rates of  Tulbaghia  Violacea  at two different  temperatures. The tubule elongation rate was  17.4 µm/min for the control and  3.00 µm/min for the variable. Error bars denote one standard deviation (1.95 µm/min  and  0.279 µm/min, respectively)  above and below the mean. Discussion: The results appear to support the hypothesis, where  Delosperma  cooperi  was positively affected by the increased  temperature  by approximately  a 0.140 µm/min  and 40% germination  improvement.   The result shows that the higher temperature yielded in an improvement in both percentage germination and pollen tube length growth  at a significant level (P10  value is higher than 2. Q10  is a unit-less measurement that establish a temperature coefficient  that correlates a system’s change to temperature difference  (of 10 °C)  (SITE 4) In addition,  the  higher percentage germination was observed from the higher temperature control  correspond to an article  in which  Delosperma cooperi  is more adapted to a higher temperature environment  due to  increased metabolic rate under temperature stress  (SITE 5). The results of  Delopserma  cooperi  were compared with  Tulbaghia  violacea  and suggest that the increased temperature had the opposite effect on  Tulbaghia  violacea, where  pollen germination percentage and pollen tube growth were more effective in the room temperature control.  Tulbaghia violacea  is known to be better suited in the colder environment  while high  temperatures  restrict their germination (SITE 6). However, the data was determined to be not significantly significant.  (P>0.6).   A possible future experiment includes testing a greater variety of indigenous  flower pollens  under more temperature variances. The experiment provided a glimpse into how certain plants would respond to  the consequences of  global  warming  and more studies are needed for a more comprehensive overview.   References Leistner, O. A. (ed.). 2000.  Seed plants of southern Africa: families and genera. Strelitzia10. National Botanical Institute, Pretoria. Mozaffar Ebrahim Edmund John Pool (2010). The effect of  Tulbaghiaviolacea  extracts on testosterone secretion by testicular cell cultures.  Journal of  Ethnopharmacology  132(1): 359–361 Reyes, A.B.,  Pendergast, J.S., and  Yamazaki, S. 2008. Mammalian peripheral circadian oscillators are temperature compensated. J.Biol. Rhythms 23: 95-98. â€Å"Global Warming Facts.† 2007. 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