Effects of below- and above-ground herbivores on plant growth,flower visitation and seed set

Separate and combined effects of root and leaf herbivores on plant growth, flower visitation and seed set were tested in a factorial experiment using potted mustard, Sinapis arvensis, at an old fallow field. A 50% leaf removal by cabbageworms (Pieris rapae) when the seedlings had their first four leaves reduced plant height and shoot mass, and delayed the onset of flowering. Root herbivory by two wireworms (Agriotes sp.) over the whole experiment changed flower visitation; the number of flower visitors per plant was higher in plants with root herbivores than in plants without root herbivores. Combined leaf and root herbivory affected flowering period, number of fruits per plant and number of seeds per fruit. Plants attacked by leaf and root herbivores had a shorter flowering period and produced fewer fruits per plant than plants with root herbivores only. Although the experimental plants faced major herbivore-induced growth changes, plant reproduction (seed set and weight per plant) was similar in all treatments, documenting their ability to effectively compensate for leaf and root herbivory.     

4种秦艽属植物不同器官中4种环烯醚萜苷成分含量的比较分析

利用HPLC法测定了秦艽(Gentiana macrophylla Pall.)、粗茎秦艽(G.crassicaulis Duthie ex Burk.)、麻花秦艽(G.straminea Maxim.)和小秦艽(G.dahurica Fisch.)根、茎、叶和花中4种环烯醚萜苷成分(包括马钱苷酸、獐牙菜苦苷、龙胆苦苷和獐牙菜苷)的含量,并对来源于不同产地秦艽和小秦艽不同器官4种环烯醚萜苷成分的含量进行了比较。结果显示:4种秦艽属植物不同器官4种环烯醚萜苷成分含量差异明显,来源于3个产地(陕西太白、甘肃西河乡和马狭)的秦艽和2个产地(青海互助和陕西麟游)的小秦艽不同器官中4种环烯醚萜苷含量也均具有明显差异。4种秦艽属植物根、茎、叶和花中龙胆苦苷和马钱苷酸总量分别为质量分数5.996%～10.869%、0.310%～4.065%、0.235%～4.138%和0.545%～5.591%;根中獐牙菜苦苷和獐牙菜苷的质量分数分别为0.516%～0.953%和0.042%～0.210%,茎中分别为0.173%～0.383%和0.031%～1.700%,叶中分别为0.068%～0.684%和0.020%～3.208%,花中分别为0.460%～0.832%和0.138%～3.827%。粗茎秦艽各器官龙胆苦苷和马钱苷酸总量均最高,小秦艽各器官龙胆苦苷和马钱苷酸总量均最低,总体上,秦艽和粗茎秦艽中龙胆苦苷和马钱苷酸总量高于小秦艽和麻花秦艽;小秦艽茎、叶和花中獐牙菜苷含量均最高,而秦艽茎和叶及粗茎秦艽花中獐牙菜苷含量均最低。4种秦艽属植物根部龙胆苦苷和马钱苷酸含量均明显高于茎、叶和花,獐牙菜苦苷在根和花中的积累较多,獐牙菜苷在花中的含量均相对最高。产自青海互助的小秦艽茎、叶和花中獐牙菜苷含量均最高,质量分数分别为2.884%、5.215%和7.321%。研究结果表明:4种环烯醚萜苷成分含量不但与植物种类和器官有关,而且与产地和采样时间也有关。     

栽培与野生化血丹不同部位中两种化学成分含量分析

为探讨并分析栽培与野生化血丹植株中不同部位中两种化学成分的含量差异,该研究采用超声法提取、高效液相色谱法(HPLC)测定栽培与野生化血丹根、茎、叶、花、混合样等部位中桃叶珊瑚苷和梓醇的含量,并进行比较。结果表明:(1)桃叶珊瑚苷在栽培与野生化血丹植株内均有分布,含量均以根中最高,其在栽培与野生化血丹植株内的含量表现分别为根叶混合样茎花、根混合样茎花叶,栽培化血丹不同部位中桃叶珊瑚苷的含量均高于野生化血丹。(2)梓醇在栽培化血丹的茎中未检出,在栽培与野生化血丹其他部位均有分布,含量均以叶中最高,其在栽培与野生化血丹植株内的含量分别表现为叶花混合样根、叶混合样茎花根,野生化血丹不同部位中梓醇的含量均高于栽培化血丹。(3)桃叶珊瑚苷和梓醇在栽培和野生化血丹植株不同部位中的含量均存在显著差异(P0.05),栽培与野生同一部位间总体上无显著差异,为该濒危药用植物资源药用部位选择和合理开发利用提供实验参考。     

Evaluation of noni (Morinda citrifolia L.) juice antiproliferative activity using the Helianthus tuberosus classical in vitro growth model system

Morinda citrifolia L. (noni) is a tropical plant that has been used for centuries in traditional medicine for numerous purposes and, nowadays, is largely commercialised on the worldwide market as a dietary supplement. Long-term in vitro cultures of Helianthus tuberosus dormant parenchyma explants constitute a classical growth model that can be used to evaluate the proliferative or antiproliferative and/or cytotoxic effects of different mixtures of chemicals present in food or with putative pharmacological applications. Explants of dormant tubers were cultured in vitro with 2%, 10% and 20% (v/v) of noni fruit juice. After four weeks of culture, explant cell growth was reduced 40.5%, 72.5% and 73.9%, respectively, by 2%, 10% and 20% (v/v) of noni juice in comparison to untreated controls. Our results demonstrated that noni fruit juice possesses strong antiproliferative capacity, low cytotoxicity and moderate antioxidant activity.     

p-CPA increases the endogenous IAA content of parthenocarpic muskmelon fruit

We examined the effects of seed formation andpara-chlorophenoxyacetic acid (p-CPA)treatment on the growth and endogenous indole acetic acid (IAA) content ofmuskmelon fruit. The growth of parthenocarpic muskmelon fruit induced by 1-(2-chloro-4-pyridyl)-3-phenylurea (CPPU) declined 15 days after anthesis (DAA),resulting in smaller fruit than those pollinated at harvest.p-CPA improved the growth of parthenocarpic fruit thatweretreated between 10 and 25 DAA. Endogenous IAA levels in the seedsof artificially pollinated fruit were at their highest at 10 DAA,then decreased, and increased again after 30 to 45 DAA, whereas,the levels in the empty seeds of parthenocarpic fruit were significantly lowerthroughout development. Although endogenous IAA levels in the placenta ofpollinated fruit were lower than those in the seeds, the changing patterns werevery similar to those in the seeds. Endogenous IAA levels in the mesocarp ofpollinated fruit remained lower than those in the placenta throughout fruitgrowth, and the pattern of change was similar to that of the placenta. Levelsinthe seed, placenta and mesocarp of p-CPA-nontreatedparthenocarpic fruit stayed lower than those in pollinated fruit.p-CPA increased the levels of IAA in the seeds, placenta,and mesocarp of parthenocarpic fruit after the first treatment (10DAA) to 15 DAA, while those in the mesocarp increasedsignificantly after the second treatment (25 DAA), but did notincrease in empty seed and placenta.     

Water Relations of Seed Development and Germination in Muskmelon (Cucumis melo L.) : I. Water Relations of Seed and Fruit Development

Total water potential (ψ), solute potential, and turgor potential of field-grown muskmelon (Cucumis melo L.) fruit tissue (pericarp) and seeds were determined by thermocouple psychrometry at 5-day intervals from 10 to 65 days after anthesis (DAA). Fruit maturity occurred between 44 and 49 DAA, and seed germination ability developed between 35 and 45 DAA. Pericarp ψ was essentially constant at approximately −0.75 megapascal (MPa) from 10 to 25 DAA, then decreased to a minimum value of −1.89 MPa at 50 DAA before increasing to −1.58 MPa at 65 DAA. Seed ψ remained relatively constant at approximately −0.5 MPa from 10 to 30 DAA then decreased to −2.26 MPa at 50 to 60 DAA before increasing to −2.01 MPa at 65 DAA. After a rapid increase to 20 DAA, seed fresh weight declined until 30 DAA due to net water loss, despite continuing dry weight gain. As fruit and seed growth rates decreased, turgor potential initially increased, then declined to small values when growth ceased. A disequilibrium in ψ was measured between seeds and pericarp both early and late in development. From 20 to 40 DAA, the ψ gradient was from the seed to the tissue, coinciding with water loss from the seeds. From 50 to 65 DAA, seed ψ decreased, causing a reversal of the ψ gradient and a slight increase in seed water content. The partitioning of solutes between symplast and apoplast may create and maintain ψ gradients between the pericarp and seed. The low solute potential within the pericarp due to solute accumulation and loss of cellular compartmentation during ripening and sensecence may be involved in prevention of precocious germination of mature seeds.     

Antioxidant efficacy of iridoid and phenylethanoid glycosides from the medicinal plant Teucrium chamaedris in cell-free systems

Twelve glycosides, seven iridoids and five phenylethanoids, have been isolated from leaf and root methanolic extracts of Wall Germander (Teucrium chamaedrys), a Mediterranean species historically used as a medicinal plant. Among them, three iridoid and one phenylethanoid glycosides have been isolated and characterized for the first time. All of the structures have been elucidated on the basis of their spectral data, especially 1D and 2D NMR experiments.The antioxidative properties of pure metabolites, as well as of crude organic extracts of the plant, have been analyzed on the basis of their DPPH radical scavenging capability. The antioxidant capacity in cell-free systems of the isolated metabolites was carried out by measuring their capabilities to inhibit the synthesis of thiobarbituric acid reactive species in assay media using as oxidable substrates a vegetable fat and the pentose sugar 2-deoxyribose and to prevent oxidative damage of the hydrosoluble bovine serum albumin (BSA) protein. Phenylethanoid glycosides resulted efficacious DPPH radical, while iridoid glycosides prevent massively the 2-deoxyribose and BSA oxidations in assay media.     

Composition of Lipid-derived Polymers from Different Anatomical Regions of Several Plant Species

The composition of the aliphatics of the protective cuticular polymers from different anatomical regions from several plant species was determined by combined gas-liquid chromatography and mass spectrometry of the depolymerization products derived from the polymers. The polymer from the aerial parts of Vicia faba showed similar composition; dihydroxypalmitic acid was the major (>85%) component of the cutin covering leaves, petioles, flower petals and stem with smaller amounts of palmitic acid and ω-hydroxy palmitic acid. On the other hand, the chief components of the polymer from the tap root were ω-hydroxy C_16:0 and C_18:1 acids and/or the corresponding dicarboxylic acids. The positional isomer composition of the dihydroxy C₁₆ acids was shown to be dependent upon anatomical location, developmental stage, and light. Apple cutin from rapidly expanding organs (flower petal and stigma) was shown to contain predominately C₁₆ family acids whereas the C₁₈ family dominated in cutin of slower growing organs (leaf and fruit). The composition of the aliphatic components of cutin found in the seed coats of pea, corn, barley, and lettuce was found to be similar to that of the cuticular polymer of the leaves in each species.     

Iridoid patterns in Galium L. and some phylogenetic considerations

From 19 species of Galium, members of 6 European sections of the genus, 24 compounds were isolated, namely 16 iridoid glucosides, 2 secoiridoid glucosides and 6 triterpene saponins (the later found only in G. rivale (Sibth. & Sm. Griseb.) The iridoid content was analyzed by thin layer chromatography - densitometry. An effort was made to clarify interspecies relationships, based on the obtained results and previous data. Generally, a nearly uniform iridoid pattern in the studied species was observed. Nevertheless, some distinctions gave reason the following chemical characters to be treated as taxonomic markers: iridoids, secogalioside (characteristic of G. mollugo group), iridoids V1 and V2 (G. humifusum Bieb. and G. verum L.), 6-acetylscandoside (G. incurvum group and G. verum) and the triterpene saponins, rivalioside A and rivalioside C (characteristic of G. rivale). The studied species regarding to the iridoids could be attributed to three lines of evolutionary differentiation. One line is leading to the differentiation of G. rivale. It contains specific triterpenoids as well as iridoid acids, which show parallel development of both glyceraldehyde 3-phosphate/pyruvate and mevalonate biosynthetic routes in this species. A second line includes G. mollugo and G. incurvum species groups and the species G. humifusum and G. verum. Variety of iridoid esters, hydroxy and carboxy derivatives of iridoids and secoiridoids characterised this line. Third line comprises the remaining studied species, members of different sections and species groups. They posses a nearly identical iridoid pattern, which suggests a convergent evolution regarding to the iridoids.     

海拔对全缘叶绿绒蒿植株性状和花特征的表型选择分析

为了研究海拔差异对植株性状、花特征表型选择的影响,以青藏高原高寒草甸的全缘叶绿绒蒿（Meconopsis integrifolia）为研究材料,于盛花期内,测定不同海拔（4 452、4 081和3 681 m）种群中个体植株性状、花特征、单果结实数并进行统计分析,采用线性回归模型估计不同海拔种群间植株性状、花特征所受的表型选择（选择差与选择梯度）。结果表明：（1）随着海拔升高,全缘叶绿绒蒿植株性状、花特征及单果结实数显著降低,海拔越高的种群中株高越矮、叶面积越小、花数越少、花越小、单果结实数越低。（2）不同海拔种群中各性状的表型选择存在差异,较低海拔（3 681 m）种群中花数、花大小具有显著的选择差和选择梯度,表现为花越多、花越大的个体雌性适合度越高;海拔较高（4 081 m）的种群中株高、叶面积及花数更容易受到选择,表现为植株越高、叶面积越大、花越多的个体雌性适合度越高;海拔最高（4 452 m）的种群中叶面积与花数的选择梯度接近显著。（3）植物性状分化伴随着海拔的变化而呈现出差异,较低海拔种群中花特征容易受到选择,而较高海拔种群中可能由于传粉者稀少、资源限制等因素使得株高、叶面积更容易受到选择。     

Floral herbivory at different stages of flower development changes reproduction in <Emphasis Type="Italic">Iris gracilipes</Emphasis> (Iridaceae)

Floral herbivores and pollinators are major determinants of plant reproduction. Because interaction of floral herbivores and pollinators occurs when herbivores attack the flowers in the bud and flower stages and because the compensatory ability of plants is known to differ according to the timing of herbivory, the effects of herbivory may differ according to its timing. In this study, we investigated the effects of floral herbivory at different stages on fruit production and seed/ovule ratio at two sites of large populations of the perennial herb, Iris gracilipes for 2 years. Herbivory at the bud and fruit stages both tended to have negative effects on fruit production, but the former caused more severe damage. On the other hand, herbivory at the flower stage tended not to have negative effects on fruit production because the degree of flower loss was smaller in the flower stage. Although herbivory decreased fruit production, flowers did not compensate for the damage by increasing the seed/ovule ratio because reproduction of I. gracilipes was limited by pollen availability rather than resources. These results indicate that floral herbivory at different stages has different effects on plant reproduction.     

Variation in Gender and Flower‐Size Dimorphism in the Dioecious Tree Dombeya ciliata,an Endemic to La Reunion Island1

The genus Dombeya is an important component of tropical forests in west Africa, Madagascar, and the Mascarene islands, but little is known about the reproductive biology of its members. In this study, we quantified gender variation and flower‐size variation in three populations of the dioecious tree Dombeya ciliata, an endemic of La Reunion Island (Indian Ocean). Variation among the three populations was observed for three characters. First, the high elevation population had strict males and females, whereas in the two low elevation populations, males were inconstant, with > 50 percent of the males set a small number of fruit. Second, females showed greater seed production at high elevation. Third, flower‐size dimorphism was greater at high elevation because male flowers were larger than female flowers.     

Water Relations of Seed Development and Germination in Muskmelon (Cucumis melo L.) : III. Sensitivity of Germination to Water Potential and Abscisic Acid during Development

Muskmelon (Cucumis melo L.) seeds are germinable 15 to 20 days before fruit maturity and are held at relatively high water content within the fruit, yet little precocious germination is observed. To investigate two possible factors preventing precocious germination, the inhibitory effects of abscisic acid and osmoticum on muskmelon seed germination were determined throughout development. Seeds were harvested at 5-day intervals from 30 to 65 days after anthesis (DAA) and incubated either fresh or after drying on factorial combinations of 0, 1, 3.3, 10, or 33 micromolar abscisic acid (ABA) and 0, −0.2, −0.4, −0.6, or −0.8 megapascals polyethylene glycol 8000 solutions at 30°C. Radicle emergence was scored at 12-hour intervals for 10 days. In the absence of ABA, the water potential (Ψ) required to inhibit fresh seed germination by 50% decreased from −0.3 to −0.8 megapascals between 30 and 60 DAA. The Ψ inside developing fruits was from 0.4 to 1.4 megapascals lower than that required for germination at all stages of development, indicating that the fruit Ψ is sufficiently low to prevent precocious germination. At 0 megapascal, the ABA concentration required to inhibit germination by 50% was approximately 10 micromolar up to 50 DAA and increased to >33 micromolar thereafter. Dehydration improved subsequent germination of immature seeds in ABA or low Ψ. There was a linear additive interaction between ABA and Ψ such that 10 micromolar ABA or −0.5 megapascal osmotic potential resulted in equivalent, and additive, reductions in germination rate and percentage of mature seeds. Abscisic acid had no effect on embryo solute potential or water content, but increased the apparent minimum turgor required for germination. ABA and osmoticum appear to influence germination rates and percentages by reducing the embryo growth potential (turgor in excess of a minimum threshold turgor) but via different mechanisms. Abscisic acid apparently increases the minimum turgor threshold, while low Ψ reduces turgor by reducing seed water content.     

Bat frugivory in two subtropical rain forests of Northern Argentina: Testing hypotheses of fruit selection in the Neotropics

Phyllostomid bats are prominent components of mammalian assemblages in the Neotropics. With many species specialized in frugivory, phyllostomids represent major partners of fleshy-fruited plants in the mutualism of seed dispersal. Here we present dietary data from two subtropical rainforests of Argentina, where fruit diversity is low and thus offer unique opportunities to test hypotheses of diet selection originally proposed for species-rich tropical assemblages. Particularly, we tested whether frugivorous phyllostomids exhibit pronounced dietary specialization in core plant taxa where fruit offer is greatly reduced as compared to tropical rainforests. We analyzed dietary overlap and niche breadth of subtropical frugivorous bats on the basis of >1000 dietary records plus >500 samples from a previous study in the region. We show that in the subtropics, frugivores from different genera remain faithful to their respective core plant taxa with few exceptions, rather than shifting toward alternative fruit resources available in the study sites. This supports predictions of specialization, which is confirmed to have a deep historical origin. The response of phyllostomid ensembles to restricted fruit diversity is at the level of species composition: absence of species for which preferred fruits do not occur in the sites. Taken together, these data lend strong support to hypotheses that explain coexistence of frugivorous phyllostomids on the basis of dietary specialization on core plant taxa with chiropterochorous fruits.     

Chemical Traits of Hemiparasitism in Odontites luteus

The study of the monoterpene glycosides content of Odontites luteus has shown the presence of a total of fifteen iridoid glucosides. The presence of compounds 1  –  5 and 7  –  10 is perfectly on‐line with both the biogenetic pathway for iridoids biosynthesis in Lamiales and the current botanical classification of the species. On the other side, the presence of compounds like agnuside ( 6 ), adoxosidic acid ( 11 ), monotropein ( 12 ), 6,7‐dihydromonotropein ( 13 ), methyl oleoside ( 14 ) and methyl glucooleoside ( 15 ) is of high interest because, first of all, they have never been reported before in Lamiales. In second instance, the majority of the last compounds are formally derived from a different biogenetic pathway which involves deoxyloganic acid/loganin and led to the formation of decarboxylated iridoid showing the 8β‐configuration. Furthermore, a second abnormality was found during our study and this regards compounds 14 and 15 which are seco‐iriodids and thus not typical for this family. The presence of these unusual compounds, biogenetically not related to species belonging to Lamiales, is a clear evidence of the metabolites transfer from the hosts. In fact, the collection area is also populated by species belonging to Oleaceae and Ericaceae which could be the possible hosts since the biosynthesis of seco‐iridoids and or iridoids related to deoxyloganic acid/loganin pathway, with the 8β‐configuration, is well documented in these species.     

Effects of above- and belowground herbivory on growth,pollination, and reproduction in cucumber

Plants experience unique challenges due to simultaneous life in two spheres, above- and belowground. Interactions with other organisms on one side of the soil surface may have impacts that extend across this boundary. Although our understanding of plant–herbivore interactions is derived largely from studies of leaf herbivory, belowground root herbivores may affect plant fitness directly or by altering interactions with other organisms, such as pollinators. In this study, we investigated the effects of leaf herbivory, root herbivory, and pollination on plant growth, subsequent leaf herbivory, flower production, pollinator attraction, and reproduction in cucumber (Cucumis sativus). We manipulated leaf and root herbivory with striped cucumber beetle (Acalymma vittatum) adults and larvae, respectively, and manipulated pollination with supplemental pollen. Both enhanced leaf and root herbivory reduced plant growth, and leaf herbivory reduced subsequent leaf damage. Plants with enhanced root herbivory produced 35% fewer female flowers, while leaf herbivory had no effect on flower production. While leaf herbivory reduced the time that honey bees spent probing flowers by 29%, probing times on root-damaged plants were over twice as long as those on control plants. Root herbivory increased pollen limitation for seed production in spite of increased honey bee preference for plants with root damage. Leaf damage and hand-pollination treatments had no effect on fruit production, but plants with enhanced root damage produced 38% fewer fruits that were 25% lighter than those on control plants. Despite the positive effect of belowground damage on honey bee visitation, root herbivory had a stronger negative effect on plant reproduction than leaf herbivory. These results demonstrate that the often-overlooked effects of belowground herbivores may have profound effects on plant performance.     

Iridoids and phenylethanoids in Lagotis integrifolia and Wulfeniopsis amherstiana (Plantaginaceae)

In a chemosystematic investigation of Wulfeniopsis amherstiana we have isolated four common iridoid glucosides as well as the esters 3″- and 4″-Cinnamoyl 6-O-rhamnopyranosylcatalpol. Furthermore the plant contained mannitol, arbutin, and four caffeoyl phenylethanoid glucosides, namely plantamajoside, aragoside and two new acetyl derivatives of the latter, named amherstianoside A and B. From Lagotis integrifolia we have obtained mannitol and three common iridoid glucosides together with the 8,9-unsaturated iridoids arborescosidic acid and anagalloside. The results show that the genus Wulfeniopsis is chemically different from Wulfenia and that it is closer related to Veronicastrum.     

Gibbons (Nomascus gabriellae) provide key seed dispersal for the Pacific walnut (Dracontomelon dao), in Asia's lowland tropical forest

Understanding the mutualisms between frugivores and plants is essential for developing successful forest management and conservation strategies, especially in tropical rainforests where the majority of plants are dispersed by animals. Gibbons are among the most effective seed dispersers in South East Asia's tropical forests, but are also one of the highly threatened arboreal mammals in the region. Here we studied the seed dispersal of the Pacific walnut (Dracontomelon dao), a canopy tree which produces fruit that are common in the diet of the endangered southern yellow-cheeked crested gibbon (Nomascus gabriellae). We found that gibbons were the most effective disperser for this species; they consumed approximately 45% of the fruit crop, which was four times more than that consumed by macaques – the only other legitimate disperser. Gibbons tracked the temporal (but not spatial) abundance of ripe fruits, indicating this fruit was a preferred species for the gibbon. Both gibbons and macaques dispersed the majority (>90%) of the seeds at least 20 m away from parent crowns, with mean dispersal distances by gibbons measuring 179.3 ± 98.0 m (range: 4–425 m). Seeds defecated by gibbons germinated quicker and at greater rates than seeds spat by macaques, or in undispersed fruits. Gibbon-dispersed seeds were also more likely to be removed by unknown seed predators or unknown secondary dispersers. Overall, gibbons play a key role in the regeneration of the Pacific walnut. Our findings have significant implications both for the management of the Pacific walnut tree dominating tropical rainforest as well as the reintroduction program of the Southern yellow-cheeked crested gibbon.     

不同发育时期黄皮种子脱水敏感性的研究

自花后４６ｄ到８８ｄ果实成熟．黄皮种子的发芽率由０升至１００％．而活力指数逐渐上升,到花后７４ｄ达到最大值,之后略有下降．每粒种子的呼吸强度在花后４６－６７ｄ持续增加,此后则渐渐减弱,但湿藏２ｄ后又回升．黄皮种子的发育明显超前于果实．花后７４ｄ时．每粒种子的干重已接近最大值,这时种子活力最大．而果实的鲜重虽然已接近最大值．但其干重却只有成熟时的７３％。花后４６－５３ｄ的种子,其发芽率小于１００％,轻微脱水能提高种子的发芽率及活力指数,花后６０ｄ至果实成熟．种子发芽率均为１００％．这时任何程度的脱水都会引起活力指数的下降,但不同发育时期的黄皮种子耐脱水力有差别．其中以花后６７ｄ的耐脱水力最强．花后８８ｄ果实成熟时种子的耐脱水力最弱。