养分供应对3种舞花姜属植物繁殖方式的影响

该研究选用的3种舞花姜属植物中,毛舞花姜(Globba barthei)和双翅舞花姜(G. schomburgkii)自然条件下开花不结实,以珠芽进行繁殖;异果舞花姜(G. racemosa)则同时以种子和珠芽进行繁殖。在人工栽培条件下,高养分处理显著增加毛舞花姜的珠芽干重((1.11±0.10) g vs. (3.08±0.69) g,p=0.010 7)、珠芽数量((30.58±2.92) vs. (74.74±9.73),p=0.000 4)、珠芽大小((10.5±1.48) mg vs. (53.50±11.42) mg,p=0.001 5)、植株营养体重((3.99±0.23) g vs. (9.67±1.17) g,p=0.000 2)和双翅舞花姜的珠芽数量((51.74±3.64) vs. (108.71±21.52),p=0.018 1)。不同养分条件下两种舞花姜的开花数量无显著差异。人工去除珠芽、花对两种舞花姜植株当年生花和珠芽的数量无显著影响(p<0.05)。自然条件下异果舞花姜不同居群间珠芽大小、珠芽数、珠芽重、果实重、种子数和营养体重等均存在极显著差异(p<0.001)。异果舞花姜各居群植株珠芽数和营养体重(r=0.901,p<0.05)、珠芽重和珠芽大小 (r=0.849,p<0.05) 呈显著正相关;果实重和种子数(r=0.998,p<0.05) 呈显著正相关。土壤因子主成分分析表明前3个主成分提供的信息量分别为50.575%、18.204% 和11.883%,其中第一主成分中的全氮(0.959)、速效氮(0.885)和有机质(0.821)负荷量最大,第二主成分中土壤速效磷(0.824)负荷量最大。植株营养体重和土壤速效磷极显著正相关(r=0.906,p<0.01),珠芽大小与全氮(r=0.798)、速效氮(r=0.780)和有机质(r=0.821)均呈显著正相关(p<0.05)。果实重和种子数与土壤因子相关性不显著(p<0.05)。3种舞花姜的无性繁殖器官更易受到养分供应的影响,有性繁殖器官对养分供应变化响应不显著,有性和无性繁殖之间似不存在补偿关系。

THE EFFECT OF NUTRIENT SUPPLY ON SEXUAL AND ASEXUAL REPRODUCTION OF THREE SPECIES OF GLOBBA

Among the three Globba species in this study, Globba barthei and G. schomburgkii propagated only by bulbils and with no seed set while G. racemosa propagated by both seeds and bulbils under natural conditions. The aim of this study was to understand the effect of nutrition supply on the relative levels of sexual and asexual reproduction of these three species in both natural and artificial conditions and to determine whether there is compensatory mechanism that enhances sexual reproduction when asexual reproduction is constrained and vise versa.  For G. barthei and G. schomburgkii, young seedlings propagated by bulbils were planted in flowerpots (30 cm in diameter) and placed under a rain and insect proof greenhouse in XTBG. The soil medium in the flowerpots was composed of forest soil (2), coarse sand (2), peat (2) and scattered brick (1). Treatments in the experiment included: 1) high_level fertilizer supply consisted of 150 ml per pot of a 5% mixed fertilizer (N∶P∶K=15∶15∶15) once every two weeks; 2) high_level fertilizer supply (same as treatment (1)) plus removal of flowers buds everyday; 3) high_level fertilizer supply (same as treatment (1)) plus removal of bulbils once a week; 4) low_level fertilizer supply (only water supplied) 5) low_level fertilizer plus removal of flower buds everyday; 6) low_level fertilizer plus removal of bulbils once a week. The results showed that 1) high_level fertilizer supply significantly increased bulbil dry weight ((1.11±0.10) g vs. （3.08±0.69） g, p=0.010 7), bulbil number ((30.58±2.92) vs. (74. 74±9.73), p=0.000 4), bulbil size ((10.5±1.48) mg vs. (53.50±11.42) mg , p=0.001 5) and vegetative organ dry weight ((3.99±0.23) g vs. (9.67±1. 17) g, p=0.000 2) of G. barthei and the bulbil number ((51.74±3.64) vs. (108.71±21.52)，p=0.018 1) of G. schomburgkii; 2) different levels of fertilizer supply did not significantly affect the flower number of the two species (p>0.05); 3) removing bulbils or flowers had no significant effect on the number of flowers or the bulbils in the current year (p>0.05). For G. racemosa, we collected 30 individuals from six native populations through out Yunnan Province and measured the biomass and size of sexual and asexual organs of each individual. Meanwhile, we collected three soil samples from each of the six populations and analyzed the physical and chemical characteristics of the soil samples. The bulbil size, bulbil number, bulbil dry weight, fruit dry weight, seed number and vegetative organ dry weight among the six populations varied significantly (p<0.001). Bulbil number was positively correlated to vegetative organ dry weight (r=0.901, p<0.05), bulbil dry weight was positively correlated to bulbil size (r=0.849, p<0.05). Fruit dry weight was positively correlated to seed number(r=0.998; p<0.05). A principal component analysis on soil factors of the six populations indicated that the three principal factors could explain 50.58%, 18.20% and 11.88% of the total variation. Total nitrogen, available nitrogen and soil organic matter wese the main factors of the first principal component, and the loading values were 0.959, 0.885 and 0.821, respectively. Available phosphorous was the main factor for the second factor with a loading value of 0.824. Vegetative organ dry weight had a significant positive relationship with available phosphorous (r=0.906, p<0.01), bulbil size was positively related to total nitrogen (r=0.798, p<0.05), available nitrogen ( r=0.78 0, p<0.05) and soil organic matter(r=0.821, p<0.05). Fruit dry weight and seed number were not significantly correlated to any soil factors. As a whole, the asexual organs of the three Globba plants were more sensitive to different levels of nutrient supply whereas the sexual organs did not show any significant response. Compensatory mechanisms between sexual and asexual reproduction were not detected in these three species.