Variability in Early Seed Development of 26 Populations of Cuscuta campestris Yunck.: The Significance of Host, Seed Age, Morphological Trait, Light, Temperature, and Genetic Variance
, Miloš Rajković 3, Ljiljana Radivojević 1, Denitsa Teofanova 2, Dragana Božić 4 and Sava Vrbničanin 4Round 1
Reviewer 1 Report
The article contains important information about the interaction of environmental conditions and germination of the parasite C. campestris. For improving the readability of the article, I suggest to trim it and remove the not-really needed details. I also suggest to reduce the size of the tables which are heavy with too many details.
L 45-47: This sentence is not clear. Please rephrase.
L 66: What about Gramineae species? what about preferred hosts?
L 71: delete “of their seeds in soil deposits”
L 78 should be: its
L 120: No filter paper?
L 122: Why only these temperatures were selected? Why not lower temperatures? Did you expect much differences between 28C and 30C?
L 135, 153 and throughout the manuscript: C. campestris should be in italics.
L 173-179: Please shorten this too long sentence.
L 206 text should read: between and within taxa.
Table 2. Weight of 1.000 seeds (g): should be 1000 seeds (g)
L 222: Please add line space after the footnote to separate from text in L 223
L 228-230: Delete the sentence on CV as it doesn’t add any new information beyond that given in Table 2.
L 236: Why this information on CV is important?
L 251-252: Should read: “with seed maturity range of 1 to 3 years germinated significantly better......”
L 254: Does aging in paper bags is "real" aging comparable to the aging in soil??? Please elaborate.
Table 3: I suggest reorganizing Table 3 by the parameter rather than by temperatures. This way the comparison will be easier to understand.
Table 4. The comparison of germination in light and dark is a bit misleading, as the light treatment contains also the effect of alternation between day/night temperatures that affects the rate of germination. In addition, the differences are significant mostly in 1-3 y old seeds. Why? Please elaborate.
L 283: Please insert a line space between the table footnote (line 284) and the text (line 285).
L 285: susceptible to what?
L 290: Is the shoot length correlated in any way to seed size as CUS56 has the smallest 1000 seed weight (Table 1)?
Table 5: Since C. campestris germination is not light dependent, it is possible that what improves germination in the “light” treatment is the temperature alternation. Please elaborate.
Figure 3: Please improve the quality of this fig.
L 381: Please avoid repetition of results in the discussion. There is no need to show again the results, but discuss their meaning.
L 397: Please add -"find host plant in the close vicinity," identify....
L 398-404: Delete this sentence. It is not relevant.
L 436: I propose to replace with: "most important agricultural pest.”
L 437: Please delete –“seeds in our research”…
L 440 - 443: I do not understand what you want to say in this sentence. please rephrase.
L 445 Please delete: this parasitic flowering plant
L471-477: I do not understand this sentence. please clarify.
L 490, 492 and 494: C. campestris should be in Italics.
Author Response
Response to Reviewer 1
Thank Reviewer 1 for the valuable corrections and advice. All comments to amend the manuscript found in the attached files were accepted and the manuscript was changed following suggestions. We used time for a second proofreading process and did our best to clarify parts of the manuscript that needed clarification. Besides, we shortened sentences at several places for better understanding, rephrased multiple sentences to write a clearer presentation, and made a thorough revision of all parts of the manuscript.
L 45-47: This sentence is not clear. Please rephrase.
We deleted this part.
L 66: What about Gramineae species? what about preferred hosts?
We rephrased the requested part of the sentence.
L 71: delete “of their seeds in soil deposits”
We deleted the requested part of the sentence.
L 78 should be: its
We corrected the spelling.
L 120: No filter paper?
We used filter paper on seed bioassays. We added this information in the section of M&M.
L 122: Why only these temperatures were selected? Why not lower temperatures? Did you expect
much differences between 28C and 30C?
Based on our previous research (reference No X Sarić-Krsmanović et al. 2013) of seed germination of C. campestris, on temperatures above 35°C, and temperatures under 25°C germination was significantly lower. Thus, we chose temperatures (28°C, 30°C, and 35°C) in which the germination of C. campestris was high in previous studies. At the same time, due to a large number of tested populations, we had to reduce the temperature range.
L 135, 153, and throughout the manuscript: C. campestris should be in italics.
We corrected „C. campestris“ throughout the manuscript in italics.
L 173-179: Please shorten this too-long sentence.
We rephased the requested part in two sentences.
L 206 text should read: between and within taxa.
We rephrased the requested part of the sentence.
Table 2. Weight of 1.000 seeds (g): should be 1000 seeds (g)
We deleted point after 1.
L 222: Please add line space after the footnote to separate from text in L 223
We added space.
L 228-230: Delete the sentence on CV as it doesn’t add any new information beyond that given in Table 2.
We deleted this sentence.
L 236: Why this information on CV is important?
It is not important, so we deleted this sentence.
L 251-252: Should read: “with seed maturity range of 1 to 3 years germinated significantly better......”
We rephrased the requested part of the sentence.
L 254: Does aging in paper bags is "real" aging comparable to the aging in soil??? Please elaborate.
The aging of seeds in controlled conditions is certainly not the same as the aging of seeds in the soil in different weather conditions during all four seasons. Storage of seeds could be carried out in laboratory conditions or by keeping the seeds in jute bags stored in the ground. In our research, we observed seeds germination of a collection that was collected in the period from 2005 to 2019 and stored in laboratory conditions. This type of seed preservation is most comparable to seeds that reach deeper layers of soil during deep plowing, where the oscillation of external factors is smaller.
Table 3: I suggest reorganizing Table 3 by the parameter rather than by temperatures. This way the comparison will be easier to understand.
We reorganized Table 3 based on yours suggestion.
Table 4. and Table 5. The comparison of germination in light and dark is a bit misleading, as the light treatment contains also the effect of alternation between day/night temperatures that affect the rate of germination. In addition, the differences are significant mostly in 1-3 y old seeds. Since C. campestris germination is not light-dependent, it is possible that what improves germination in the “light” treatment is the temperature alternation. Please elaborate.
Some researchers [Vail et all., 1990; Benvenuti et all., 2002] believe that Cuscuta spp. do not require host-root exudates to stimulate germination, similar to some important holoparasitic weeds of the genus Orobanche and some hemiparasitic weeds in the genus Striga. Field dodder as a stem parasite is strongly impacted by light signals, which stimulate germination of its seeds and seedling growth [Orr et all., 1996; Tada et all., 1996; Haidar, 2003]. Field dodder seedlings tend to grow in the direction of light source, primarily red/far-red light, which helps them find hosts, while far-red and blue light has a significant role in prehaustorium formation. Recognition of a host occurs through phototropic mechanisms, and some authors claim that chemotropism (movement induced by chemical stimulus) and thigmotropism (movement induced by a mechanical stimulus, i.e., by touch) have equally important roles in the host recognition process [Haidar et all., 1997].
Also, the results from my Ph.D. thesis showed the positive effect of light on seed germination and early seedling growth of C. campestris. So, we believe that light can improve the germination and seedling growth of C. campestris. Furthermore, agronomic experience in dodder control shows that the main sources of crop infestation are the ruderal edge of the field where the seeds survive in the surface layers where they are exposed to sunlight for most of the year.
L 283: Please insert a line space between the table footnote (line 284) and the text (line 285).
We inserted a line space.
L 290: Is the shoot length correlated in any way to seed size as CUS56 has the smallest 1000 seed weight (Table 1)?
Based on the results shown in Table 2, it can be seen that 5 populations (CUS56, CUS3, CUS5, CUS8 and CUS11) have the same weight of 1000 seeds (0.6 g). However, if we compare the lengths of seedlings of these 5 populations whose seeds were exposed to the same germination temperature, it can be seen that the length variations between these populations are greater than 100%. Therefore, the assumption is that these two parameters, the weight of 1000 seeds and the length of the seedlings, are not correlated.
Figure 3: Please improve the quality of this fig.
We improved the quality of Figure 3.
L 397: Please add -"find host plant in the close vicinity," identify....
We added this part in the sentence.
L 398-404: Delete this sentence. It is not relevant.
We deleted this part.
L 436: I propose to replace with: "most important agricultural pest.”
We replaced the with the word „pest“.
L 437: Please delete –“seeds in our research”…
We deleted this part of the sentence.
L 440 - 443: I do not understand what you want to say in this sentence. please rephrase.
We deleted this sentence.
L 445 Please delete: this parasitic flowering plant
We deleted this part of the sentence.
L471-477: I do not understand this sentence. please clarify.
We rephrased this sentence.
L 490, 492 and 494: C. campestris should be in Italics.
We corrected „C. campestris“ throughout the manuscript in italics.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Reconsider its publication as a book chapter or a review article. It is too long (36 pages) and therefore very hard to get conclusions for practical purposes.
Author Response
Response to Reviewer 2
Comments and Suggestions for Authors
Reconsider its publication as a book chapter or a review article. It is too long (36 pages) and therefore very hard to get conclusions for practical purposes.
Thank Reviewer 2 for the valuable advice. We realize the manuscript is long, but still, it is not much bigger than a regular paper. Also, data on this research are not published before, thus our main idea was to represent them as the research article.
Author Response File: Author Response.docx
Reviewer 3 Report
The study is focus on different Cuscuta campestris genotypes and their behaviour in germination and growth under different temperatures and light. The high amount of genotypes distributed by distinct regions in Serbia makes the study of interest. The English is correct and the methodology of the manuscript adequate.
However, for publications some aspects must be solved.
In the material and methods, a table with the mean temperatures and rainfall patterns in the different locations is needed, since the germination does not depend only on temperature and soil humidity and the maximum and minimum temperatures during growing season are also key factors.
In the discussion a paragraph concerning genetic background according to phylogenetic trees between different genotypes is needed. And if there is no relation between genetic background and geographical distribution it must be mention in the conclusion.
The conclusion in general must be improved, indicating the genotypes and areas more susceptible for C. Campestris germination under the climatic conditions of the area.
Author Response
Response to Reviewer 3
Thank Reviewer 3 for the valuable corrections and advice. All comments to amend the manuscript found in the attached files were accepted and the manuscript was changed following suggestions. We used time for a second proofreading process and did our best to clarify parts of the manuscript that needed clarification. Besides, we shortened sentences at several places for better understanding, rephrased multiple sentences to write a clearer presentation, and made a thorough revision of all parts of the manuscript.
In the material and methods, a table with the mean temperatures and rainfall patterns in the different locations is needed, since the germination does not depend only on temperature and soil humidity and the maximum and minimum temperatures during growing season are also key factors.
Data about mean temperatures and rainfall are usually included for field research. We performed our research under laboratory conditions. We assume that they may have some effect on the quality of the produced seeds, but not of crucial importance. Moreover, the sites of the seed collection are situated within a small region in Serbia and therefore, there are no substantial climatic differences. Therefore, we prefer, if possible, not to include these data as it will additionally increase the size of the manuscript without adding substantial information.
In the discussion, a paragraph concerning genetic background according to phylogenetic trees between different genotypes is needed. And if there is no relation between genetic background and geographical distribution it must be mentioned in the conclusion.
We indeed did not find any clear relation between genetic variability and geographic distribution, which is discussed on lines 434-447. We extended this in the conclusions.
The conclusion, in general, must be improved, indicating the genotypes and areas more susceptible for C. campestris germination under the climatic conditions of the area.
We extended the Conclusions. We added some conclusions about genetic diversity.
Author Response File: Author Response.docx
